# Anatomical Record 8 (1914)

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# THE ANATOMICAL RECORD

EDITORIAL BOARD

Ira7xg Hakdestt

Tulane University

Claeence M. Jackson

University of Minnesota

Thomas G. Lee

University of Minnesota

Frederic T. Lewis

Harvard University

Waeren H. Lewis

Johns Hopkins University

Charles F. W. McClcke

Princeton University

WiLUAM S. Miller

University of Wisconsin

Florence R. Sarin

Johns Hopkins University

George L. Streeter

University of Michigan

G. Carl Huber, Managing Editor

1330 Hill Street. Ann Arbor, Michigan

VOLUME 8 1914

PHILADELPHIA THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY

## Contents

1914

No. 1 JANUARY

J. Parsons Schaeffer and Louis H. Nachamofsky. Some observations on the anatomy of the upper extremities of an infant with complete bilateral absence of the radius. Six figures 1

James F. Cobey. An anomalous right subclavian artery. Two figures 15

J. Douglas Perkins, Jr. An anomalous muscle of the leg: Peronaeo-calcaneus internus. Three figures •. 21

R. M. Strong. Some ideas in laboratory equipment. Four figures 27

Xo. 2 FEBRUARY

Charles R. Stockard. The artificial* production of eye abnormalities in the chick embryo. Two plates 33

R. A. McGarry. a case of patency of the pericardium and its embryological significance. One figure 43

George G. Scott. The percentage of water in the brain of the smooth dog-fish. Mustelus canis 55

Randolph West. A note on the presence of a musculus cleido-atlanticus m the domestic cat (Felis domestica). One figure 65

Proceedings of the American Association of Anatomists. Thirtieth session: Abstracts: Demonstrations ^ 69

No. 3 MARCH

Arthur William Meyer. The occurrence of supernumerary spleens in dogs .-ind cats.

with observations on corpora libera abdominalis. IV. Studies on hemal nodes.

Twelve figures M7

J. Playpair McMurrich. The nomenclature of the carpal bones 173

No. 4 APRIL

J. B. John.ston. The nervus terminalis in man and mammals. Nine fisures IS5

Samuel T. Orton. A note on the circulation of the cornu ammonia. Two figures 199

Adam M. Miller and J. E. McWhurter. Expcritnents on the development of blood

vessels in the area pelluciiia and embryonic body of the chick. Thirteen figures.. . 303

Reproduction of models by The Wistar Institute 22S

List of members of the American .Association of .Anatomists -JQ

iii

iv CONTENTS

No. 5 MAY

J. G. KuAMEH and T. \V. Todd. The distribution of the nerves to the arteries of the

arm, with a discussion of the clinical values of results. Five figures 243

Harkis K. Sa.stee. The brain of ft black monkey (Macacus maurus) : The relative prominence of <iifTerent gyri. lour figures 257

Charle-s E. Joh.vson. An additional case of pancreatic bladder in the domestic cat.

One figure 267

Hahoij) L. Kearney. On the relative growth of the organs and parts of the embryonic and young dogfish (Mustelus canis) 271

HoBEUT Hexnett Bean. The eruption and decay of the permanent teeth 299

Arthur Wii.uam Meyer. 0.steology rcdivivus: \ criticism 303

No. JUNE

Barto.n G. Dcpre and T. Winoate Todd. A transitional type of cervical rib, with a

commentary. Four figures 313

Georoe p. Leonhart. A case of stylo-hyoid ossification. Two figures 325

Richard W. Harvey. A case of multiple renal arteries. One figure 333

J, R. Driver and A. B. Denison- The morphology of the long accessorius muscle.

Four figures 341

Franklin I'aRadise Johnson. A ca.se of atresia ani in a human embryo of 26 mm.

One figure » 349

F. E. Chide.ster. Cyclopia in mammals. Twelve figures 355

F. E. Chide-ster. Twins in fish, one with a cyclopic deformity. Four figures .367

No. 7 JULY

E. K. liusKiNS. On the vascularization of the spinal cord of the pig. Five figures ... 371

Edward V M alone. A course of correlational anatonjy 393

Franklin P. Reagan. A useful modification of Mann's methyl-blue-eosin stain 401

No. 8 AUGUST

Hcsalind Wulzen. The morphology and histology of a certain structure connected

with the pars intenncdia of the pituitary body of the ox. Seventeen figures 403

J. C. Miller. Ossiculum lus 41.")

E R. HoHKiNs. Persistent arteriac branchii suporficialis, antibranchii superficialis et mediana. One figure 421

No. 9 SEPTKMHEH

H. E. Jordan, 'i In- microscopic structure of mammalian cardiac muscle with si)ecial

reference U> Bo-o:ilicd 'muscle cells.' Eight figures 423

R. R. Hensley. The thyroid gland of the opossum. Three figures 431

T. Winoate Todd. Covers for dissecting tables. Three figures "^^^

T. Winoate Todd. A tank for the preservation of anatomical material. Three figures 444 A. O. Wee8E. A simple electrical heating device for incubators, etc. Fourfigures 447

CONTENTS V

No. 10 OCTOBER

Victor J. Hats. The development of the adrenal glands of birds. Eight figures... 451 Paul S. McKibbex. Mast cells in the meninges of Xecturus and their differentiation from nerve cells. Two figures 475

No. 11 NOVEMBER

Robert Bennett Bean. A racial peculiarity in the pole of the temporal lobe of the

negro brain. Nineteen figures (three plates) 479

Leslie B. Aret. An abnormalitj' in the intestine of Necturus maculosus Raf.

Six figures 493

P. E. Smith. The development of the hypophysis of Amia calva. Ten figures 499

Richard W. Harvey. A brain macrotome. Two figures 507

No. 12 dece:mber

Shinkishi Hatai. On the weight of some of the ductless glands of the Norway and of the albino rat according to sex and variety. Five charts 511

Otto C. Glaser. On the mechanism of morphological differentiation in the nervous

system. Three figures 525

SOME OBSERA ATIOXS ON THE AXATO.MY OF THE UPPER EXTREMITIES OF AX IXFAXT WITH COMPLETE BILATERAL ABSEXCE OF THE RADIUS

J. PARSOXS SCHAEFFER AND LOUIS H. XACH.AJMOFSKY

The Anatomical Laboratory of the Yale Medical School

SIX FIGURES

On Februan' 20, 1913, the bod}- of a white, male infant, aged one day, of average size and weight reached the anatomical rooms of the Yale ^Medical School. On inspection the body appeared to be well developed and normal, save for an odd-appearing deformity of both upper extremities. At autopsy the pleural cavities were found to contain a considerable amount of blood, doubtless the result of a birth injury-.

LTpon examination of the defomied upper extremities, it was found impossible to pronate or supinate the antebrachium and hand, save for a slight alteration in position allowed by turning the humerus and ulna on their vertical axes. The hands were fixed in marked adduction; the right one making a right angle and the left one considerably less than a right angle with the antebrachium. Both hands were rotated on the ulnae so that their dorsa presented \entrad, that is, they were fixed in pronation and abutted the ulnae at their medial aspects (figs. 1 and 5).

The position of the hands indicated lack of radial support. Careful examination failed to reveal any trace of a radius in either arm. A jjrovisional diagnosis of complete absence of both radii was made. This was later confinned by Rontgen rays and bj' dissection (figs. 2 and 5).

The ulnae seemed normal in position and size. However, due to the faulty position of the hands, the distal extremities of the ulnae formed very prominent subcutane<ius points at the wrists (figs. 1 and 2).

1

THE ANATOMICAL RECORD. VOL. 8, NO. 1 JAM'ARV, lOM

2 J. PARSONS SCHAEFFER AND LOUIS H. NACHAMOFSKY

The fact of <)l)sorving the absence of both radii and of the resultant faulty position of the hands seemed of little value. It was, therefore, deemed advisable to make a careful dissection of at least one of the extremities to ascertain to what extent other anatomical errors were present. In order to study the feasibility of tendon transplantation in such cases, in an attempt to lessen the deformity and to increase the efficienc}^ of the member, a dissection of the antebrachium and hand was deemed of especial value.

The dissection was done by the junior author (Nachamofsky, ria>' many instances in the fonnation of tendons; the muscles arising or inserting by fleshy contacts where normally tendons are present.

Another fact to be noted is that those muscles normally associated with the radius, but in this case only partly differentiated, were found to attach to the ventral surface and lateral border of the ulna.

Xot only the muscles of the antebrachium and hand but many f)f the brachium and shoulder likewise were found to be abnormal.

Mwscles of shoulder. The origin of the deltoid muscle was approximately nonnal. Its insertion was, however, markedly altered. It jjassed distally from its origin; its fii)ers converging towards the lateral intermuscular septum, to which it gained inwrtion just j)roximal to the lateral cpicondyle of the humerus.

The deltoid had no insertion on the humerus, but l)ecame continuous with the teres major dor.sally; with the brachio

COMPLETE BILATERAL ABSENCE OF RADIUS

Fig. 1. Sketch of an infant witli complete bilateral absence of the radius. Especially note the abnormal position of the hands. The prominence at the wrist is caused by the distal extremity of the ulna. See text for further description of the upper extremities.

4 J. PARSONS SCHAEFFER AND LOUIS H. XACHAMOFSKY

Fi^. 2. Skianraii , , i ixtrcmilics of infant sketcho(i in fig. 1. Note

the rharartpristic position of the IuukIs and tlio complete absence of both raiiii. Ab UHUal the carpal hones show no ossification at this age.

radialis and the extensor carj)i radialis longiis and brevis muscles distally: aiul nioro or loss witli the pectoralis inajor muscle vent rally.

The supraspinatus and tlio infraspinatus and the teres minor muscles were normal save that the latter and last were inseparably mingled.

COMPLETE BILATERAL ABSENCE OF RADIUS 5

The teres major muscle at its origin was undifferentiated from an abnormalh' extensive origin of the long head of the triceps brachii muscle. Contrary to the normal course of the muscle, in passing from origin to insertion, it coursed lateral to the upper extremity of the humerus and became continuous with the deltoid, the brachio-radiaUs, and the extensor carpi radialis longus and brevis muscles. At no point was the teres major muscle directly attached to the humerus.

The latissimus dorsi muscle was inserted b}' two distinct tendinous slips. Near its insertion the lateral and somewhat larger slip terminated in a fleshy band which became incorporated with the common mass of the heads of the triceps i^rachii muscle. The faulty course of this portion of the latissimus dorsi muscle, as well as that of the teres major muscle mentioned above should here be noted. A shorter medial head of the latissimus dorsi muscle coursed cephalically and ventrally, giving a tendinous portion to insert on the humerus just distal to the subscapularis muscle and a caudal fascial expansion which gave origin to a part of the medial head of the triceps brachii muscle.

The pectoralis major muscle in addition to its normal insertion sent fibers into the deep aspect of the deltoid muscle, thus fonning an accessory muscular band one cm. wide.

Muscles of brachium. The biceps brachii muscle attempted an origin from the supraglenoid tubercle, and some of its tendinous fibers could be traced to it, but its long head mainly arose from the capsule of the shoulder joint which it materially strengthened. The short head of the muscle arose as usual irom the coracoid process of the scapula. The belly of the biceps brachii inserted (?) along the distal half of the medial and lateral surfaces and the medial and lateral epicondylic ridges of the humerus. The interval between the epicondylic ritlges was bridged over by stmie biceps brachii fibers which passed distally to insert onto the coronoid process of the ulna and to give origin to the extensor digitonmi comnmnis and the extensor digit i quint i proprius muscles. The canal thus fonned between the epicondyles of the humenis transmitted tlie median nerve lakrally and the brachial artery 7?iediaUy.

6 J. PARSONS SCHAEFFER AND LOUIS H. NACHAMOFSKY

The brachialis (iinticus) imiscle as sucli was absent. The apparent absence of this muscle together with the fact that some biceps brachii fibers inserted on the coronoid process of the ulna loads one to believe that the brachialis was incorjwrated with the bicei>s brachii fibers and that it had not differentiated from it.

The coraco-brachialis muscle arose with the short head of the bicei)s brachii nmscle from the coracoid process. It had an abnonnally extensive insertion on the humerus and into the brachial fascia.

An acromio-lnimoral muscle appeared as an anomalous band, arising from the inferior surface of the overhanging acromion process and the capsule of the shoulder joint. It inserted on the humenis just lateral to the major tubercular crista. It lay beneath the deltoid muscle. This may explain the absence of a bony insertion of the latter muscle and might be considered an is<^lated deep portion of it.

The long head of the triceps l^rachii muscle arose very extensively not only from the infraglenoid tubercle ))ut from a goodly portion of the axillary border of the scapula where it was intimately blended with the teres major muscle as mentioned in the previous paragra])h. The medial head of the triceps brachii arose along the distal third of the dorsal surface of the humeiiis. The lateral head was partly incorporated with the long head and in part arose from the tendon of insertion of the latissimus dorsi muscle. As usual it gained insertion on the olecranon process of the ulna and into the antebrachial fascia in the immediate neighborhood.

The anconaeus muscle was normal in its origin but its area of insertion was abnonnally extensive; the whole ])roximal half of the dorsal or extensor surface of the ulna was occupied by it.

Mnficlcfi of the antebrachinm and hand. The brachio-radialis muscle took its origin from the distal fibers of the deltoid muscle and from the over-lying fascia. It inserted into the transverse carpal ligament and into the antebrachial fascia. The peculiar insertion of this muscle was probably due to the rotation of the hand about the ulna. The muscle took a rather devious course:

COMPLETE BILATERAL ABSEN'CE OF RADIUS 7

Turning ventrally from its origin, it occupied a position between the extensor carpi radialis loiigus and brevis muscles medially, and the extensor pollicis longus muscle (?) laterally, lying over a mass of undifferentiated muscular tissue.

The extensor carpi radialis longus and bre\'is muscles arose by a common fleshy head of origin from the caudal portions of the deltoid and the triceps brachii muscles. They coursed distally

Fig. 3. Diagrammatic sketches of superficial (to the left) and deep (to the right) dissections of the ventral aspect of the right antebraehiiim and hand. The details of the dissection are purposely omitted. See text for description of figure. X = flexor carpi ulnaris muscle; a = palmaris longus muscle; c = flexor carpi radialis muscle; r = extensor carpi radialis longus et brevis muscles; b = brachioradialis muscle; n = ulnar nerve; p = flexor profundus digitorium muscle; y = hypothenar muscle; s = flexor digitorum sublimis muscle; u = ulna; 2 = lunibrical muscles undifferentiated; ni = undifferentiated muscle.

over the latero-central aspect of the antebrachium, following the course of the brachio-radialis muscle. Both muscles inserted on the transverse car])al ligamont medial to tlie Iirachio-radialis. The brevis was distinguishable from the longus only after tiiey had traversed half tlieir course (fig.3).

An extensor muscle of the thumb was present but did not correspond to any of the normal thumb extensors. It arose partly

8 J. PARSON'S SCHAEFFER A.VD LOlIS H. NACHAMOFSKY

inm\ tlic inosl distal hiccps hnu-liii fibois and was intimately associated with a coninion niusole mass adherent to the ventral surface of the ulna. The muscle passed distally and became superficial at the region of the carj^us where it was lateral to the extensor digitorum comnmnis muscle. Its tendon gained the dorsum of the hand by pa.ssing through the first osteo-fibrous canal on the dorsum of the wrist and it inserted on the base of the distal i)halaiLX of the thumb. On the dorsum of the hand a small nmscular sheet arose from the thumb extensor which passed medially under the tenilons of the other extensors to insert on the hypothenar fascia over the fifth metacarjial bone (fig. 4).

The extenst)r digitorum conununis nmscle was a round nmscle which arose in conunon with the extensor digiti (juiiiti proprius muscle from the distal fibers of the biceps brachii muscle, from the lateral epicondyle of the humerus, and from the antebrachial fascia. It passed suj)erficially and distally through the second osteo-fibrous canal onto the dorsum of the hand. It coursed l)etween the extensor digiti ([uiiiti proprius nuiscle medially and tlie extensor of the thumb laterally, lying over the ulna and an unilifTerentiated mass of muscle deeply placed. On the dorsum of the hand the extensor digitorum communis muscle gave off four tendons which inserted by broad fascial expansions on the j)halang('s of the second, third, fourth and fifth fingers. The more direct tendinous insertions were, however, to the distal segments (fig. 4).

The extensoj- digiti (juiiiti j)roj)rius muscle arose in common with the extensor digitorum communis muscle. It was quite superficial on the antcbrachium with the extensor carpi ulnaris muscle medial to it. On the dorsum of the hand its tendon divided, one j)art going to insert with a tendon from the extensor communis digitoniiii nmscle and the otlier becoming continuous with the fascia ov(;r the fifth metacarpal bone (fig. 4).

The extensor carpi ulnaris muscle was nonnal except for the absence of a distinct tendon of insertion. The muscle teniiinated in a broad fascial band wliicli inserted (m the medial aspect of the distal extremity of tin; ulna. Its usual insertion on t)ie fiftli metacarpal Ixoie was wanting.

COMPLETE BILATERAL ABSE^X'E OF RAD IT'S 9

The remaining muscles of the extensor group were either totally missing, as in the ease of the supinator fbrevis; muscle, or were not differentiated, but remained merely a muscle mass which lay between the extensor of the thumb and the flexors of the antebrachium. Since the flexor pollicis longus muscle was absent, it is likely that it had not differentiated from this mass. It should here be noted that the absent and undifferentiated muscles in the specimen are nonnally intimately associated with the radius, both with respect to their origin and their course.

The flexor carpi ulnaris muscle was normal in size and position. It, however, lacked a clean-cut tendon and did not find an insertion on the carpus. The only point of insertion was to the capsule of the joint between the ulna and the carpus.

The palmaris longus muscle (?) arose together with the flexor carpi ulnaris from the medial epicondyle of the humenis, and passed into the antebrachium lateral to the latter nmscle. The palmaris longus and the flexor carpi ulnaris had a common insertion on the capsule of the joint between the carpus and the ulna (fig. 3).

The flexor carpi radialis muscle (?) took its origin from the medial epicondyle of the humerus in common with other flexors, and from the distal fibers of the biceps brachii and the intenmiscular septum. It passed lateral to the pahnaris longus i?) and was separated from it in the distal half of the antebrachium l\v the ulnar nerve. The fibers of the muscle converged to a jx)int at the junction of the middle and distal thirds of the antebrachium. From this point the muscle again spread out into a triangular muscular sheet to ultimately insert on the ventral surface of the ulna and the proximal aspect of the can:)us. It is probable that the flexor carpi radialis nmscle in its distal third is nonnally more or less supported and directed by the radius. The latter being absent, the muscle dro])])ed to a secondarv support on the ulna (fig. 3).

The ])ronator (ratlii) teres muscle wa.< entirely wanting.

The flexor digitonim sublimis nuiselc (?) arose by two heads: that from the medial epicondyle was extremely small, and baroIv extended to this bony ]>()int. It also gained a slight origin

10 J. PARSONS SCHAEFFER AM) LOlIS H. XACHAMOFSKY

from tlie medial inlcnnuscular sei)tuiii. Tlie radial head of tlie imiscle dro])ped more distally and deeply, due to the absence of the radius, and arose from the lateral border of the uhia near the car]His. The latter origin was found on a deeper level than that of the flexor digitonnn jirofundus nuiscle, and in its passage into the hand it lay ventral to the mass of thenar nmscles. The two heads joined in the liand to fonn a distinct tendon which inserted on the base of the distal phalanx of the index finger. In the palm of the hand a sheet of nmscle tissue extended from the tendon of the flexor sublimis digitonmi (?) over the flexor profundus digitonnn towards the fifth metacar]ial l)one. It was not clear what tliis muscle represented (fig. 3).

The flexor digitorum ]irofundus muscle arose beneath the superficial muscles from the whole ventral surface of the ulna. It lay ventral to the second head of the flexor digitonmi sublimis muscle. The muscle was fan-shaped, converging to a point on the carpus and continuing into a tendon which sent three slips to the bases of the distal jihalanges of the third, fourth and fifth fingers (fig. 3). In the pahn the tendon passed beneath the flexor sublhnis digitorum. From the ventral surface of the tendon an undifferentiated sheet of muscle extended toward the fifth metacari:)al bone and lay beneath the accessory sheet of nmscle given off from the flexor digitonnn sublhnis. From this muscular mass two lumbrical muscles were given off for the fourth and fifth fingers (fig. 3).

The thenar muscles were represented by a small mass of undifferentiated nmscular tissue. This muscular mass arose from the superficial fascia and from the undifferentiated extensor muscular mass. It extended to the base of the second phalanx of the thumb. A distinct tendon for the mass was wanting.

The extensor pollicis longus muscle was absent as a distinct muscle. It was probably incorporated in the undifferentiated extensor mass.

The hypothenar muscles were not differentiated into individual muscles, but together formed a triangular sheet of muscle which arose from the transverse carjial ligament. The nmscular sheet inserted on the medial border of tli(> fifth metacar])al bone.

COMPLETE BILATERAL ABSENCE OF RADIUS

11

The pronator quadratus muscle was proljably represented by a mass of muscular tissue which surrounded tne distal extremity of the ulna (fig. 4) .

The palmar interossei muscles were normal.

The dorsal interossei muscles were absent except the one for the index finger.

—/■ UI71Q

Fig. 4. Diagranimatic sketch of a tlissection of the hiteral aspect of the antebrachium and of the dorsum of the hand of the right upper extremity. Only the muscles are indicated, o = flexor carpi ulnaris; h = palmaris longus and flexor carpi radialis (?) musch^s; c = extensor carpi radialis longus et brevis muscles; d = brachio-radialis muscle; c = extensor of thvuiib;/ = extensor digitorum communis muscle; g = extensor iligiti quinti proprius muscle; h = undifTerentiateii muscle; i = extensor carpi ulnaris muscle; j = pronator quadratus muscle (?); k = tendons of extensor digiti quinti projjrius muscle; / = sheet of muscle from thumb extensor.

Fig. 5. Outline drawing of the hones of the right brachium and antebrachiuni after the muscles were removed. The hand is also shown in its fixe<l position.

B. O.'^TKOLOGY

The humeiiis was shorter than nonnal. mea.suring only o cm in length. The proximal epi]ihysis wa.^ relatively extensive. l.D cm. in length. It projected cephalically and ventraily from the shaft at an angle of about 135° (fig. 5). The shaft of the humenis was more or less rounded and not easily divisible into surfaces and borders.

12

J. PARSONS SCHAEFFER AM) LOlIS H. NACHAMOFSKV

Tho rapsiilo of tlio oll)<)\v joint was vory lax and tliin. It had incorporalinl in it many iiuisclc fihors. and tho difforontiation of the various ligaments of the joint was very slight. The size of the capsular ligament i^ennittcil a rather complex elbow motion. Not only was the nonnal ginglymoid movement possible in its full extent, but a distinct trocoidal movement of the ulna on the humerus was also possible. This condition in a measure compensated for the absence of the radius and made a small degree of pronation anil supination of the antebrachimn possible.

Nerves to Coraco-bracriiaiis and Biceps Mm.

<. ^.^Suofa-scaoular N.

"- -.^ 5 rJ7C

Median M

Long Thoracic. N. Meo. Ant. Thorac. N.

(Circum(lex>

' Fig. 6. Diagram of the brachi.al jilexus of the right upper extremity. See text for description of it.

It should also here be noted that the medial aspect of the distal extremity of the ulna formed a diarthrodial joint w^ith the carpus.

The osteology of the hand and carpus appeared normal for the age of the infant.

C. NEUROLOGY

The distribution of the nerves was more or less normal, but the altered musculature necessarily complicated the arrangement of the nerves. However, the nerve supply was an aid in diiTercntiating the various muscles of the antebrachium and hand. The one striking thing about the nerves throughout the upper extremity was the unusually large size of the main trunks. The brachial plexus also deviated from its normal arrangement. A.s is indicated in the diagram of the plexus (fig. (>), the medial and lateral components of the median nerve remained independent to the level of the bend of the elbow. Ui'^ro. the components

COMPLETE BILATERAL ABSENXE OF RADfUS 13

united to form the median nerve proper. Another peculiar condition of the median nerve was the origin of its medial component firmer head) from both the medial and dorsal cords of the plexus. The musculo-cutaneous nerve (?) ended in the substance of the biceps muscle and another small nerve from the lateral cord ended in the coraco-brachialis muscle. In the diagram these nerves are designated nerves to coraco-brachialis and biceps mu.scles."

The medial anterior thoracic nerve was a branch of the middle trunk. At least the nerve so designated filled the description of the medial anterior thoracic nerve in every way save its point of origin.

The medial brachial Clesser internal) cutaneous nerve was entireh' absent.

D. COXCLUSIONS

The agenesis of the radius in this case must have been due either to a failure of the radial portion to give ri.se to an anlage, or if the latter were established, some affection must have destroyed the skeleton anlage after it had begun to differentiate. In view of the fact that there was a complete absence of the radius the natural inference is that there was a lack of origin of the element.

It is difficult to say to what extent the absence of the radius was responsible for the marked errors in the nuisculature of the upper extremity. Certainly the ab.sence of radial suj^port and stimulus must have to a great extent influenced the muscles that normally arise and insert on this bone (it will be recalled that the latter muscles were in many instances profoundly altered i.

Other antebrachial nuisdes, as well as those of the hand showetl marked errors. The faulty position of the hand, doubtless primarily caused by lack of radial support, may have been responsible for some muscle alterations, especially those of the hand and those that normally in.sert on the carpus. Lack of radial guidance and stimulus may have influ(Miced others. It is. how««ver. difficult to see how the ab.sence of the radius could have had any bearing on the development of the nuisclos of the shoulder and proximal half of the brachium. Notwithstanding, many of these

14 J. TAKSONS SCHAEFFER AND LOUIS H. XACHAMOFSKY

muscles were quite anomalous in thoir anatomy, as is indicated in the text.

It would, therefore, seem that the whole error-complex of the upper extremity was primarily due to the lack of a proper formati\e stmmlus or stimuli, and tliat the absence of the radius could merely account for secondary muscular errors due to the lack of support and stimulus normall}' supplied by this bone. The faulty position of the hand seemed purely secondary, due to lack of radial support and muscular contraction.

AX AXO.ALILOUS RIGHT SUBCLAVIAN .AJiTERY

JAMES F. COBEY The Anatomical Laboratory of the Yale Medical School

TWO FIGURES

Among the variations in the arrangement of the branches of the aortic arch in man, there is an unusual anomalous condition in which the right subclavian artery arises from the arch distal to the left subclavian. An example of the aforementioned anomaly was met with by the writer in the dissecting room of the Yale ^Medical School during the session of 1912-1913.

A description of the specimen, with an attempt to explain the embr^'ology thereof and with a suggestion of symptoms that might arise therefrom, is offered here in brief.

DESCRIPTION

The anomaly to be considered was noted in the dissection of a male, negro cadaver, aged approximately forty-five years. The right subclavian artery, instead of arising normally in conjunction with the right conuiion carotid from the innominate artery, came off as an entirely separate artery from the descending limb of the aortic arch on the left side of the body after the left subclavian artery was given off (fig. 1). The anomalous vessel reached the right arm by passing dorsal to the trachea and the esophagus across the vertebral column.

The right subclavian took its origin from a point on tiie dorsal aspect of the descending limb of the aortic arch 5 inch distal and to the right of the normally placed left subclavian artery (fig. 1). Leaving the aorta, it passed at an angle of 45 degrees to the right and cephala(i between the esophagus and the bony vertebral column. Tills direction was maintained in its further course through the neck with l)ut a slight lateral curve to the point where the first branches arose from it.

15

16 JAMES F. COBEY

As is indicated (fig. 1 ), the riglit vertebral artery was the first branch of the anomalous right subehi\ian and it came off at a distance of 4§ inches from the origin of its parent from the aorta. It therefore corresponded to tlie normal position ior the vertebral artery - a fact worthy of note on account of differences in the position of the vertebral artery in cases of anomalous subclavian arteries like this. The right subclavian artery was crossed in the root of the neck by the right pneumogastric (vagus) nerve, but the inferior (recurrent) laryngeal l)ranch of the vagus did not hook around the subclavian artery as usual. — that is, it was not recurrent, as shown in figure 1.

There was no innominate artery j)re8ent in the subject, both common carotid arteries arising separately from the arch of the aorta. The relations of the second and third parts of the right subclavian artery and the origin and distribution of its branches were perfectly normal.

EMBRYOLOGIC EXPLANATION

Embryology readily explains the anomaly described above by assuming a defect in the absorption of the primitive right aortic arch in the embryo. Absorption occurs ordinarih' distal to the point of origin of the right subclavian artery (a to b, fig. 2 B). In the case in cjuestion the position of absorption was along the fourth branchial arch (« to c, fig. 2 C). The embrj^onic right aorta became the right subclavian artery (a to x, fig. 2 C).

The position of the right subclavian so far cephalad on the left arch (arch ]iroper) of the aorta may be explained in two ways: Either there was a positi\e migration of the artery from point A' in figure 2 C to point .r in figure 2 I), or the migration is onh' apj)arent and the real change was a dragging down of the aortic arch in the mid-line by a downward movement of the heart and pulmonary system. Probably both processes progressed para passu and had a .share in bringing about adult conditions found in this case. The second \ iew gives a reason for the position of the right subclavian artery dorsal to the trachea. The pulmonary system descends ventrally with the heart through

ANOMALOUS RIGHT SUBCLAVIAN ARTERY

17

Fig. 1 Drawing from a dissection of the ventral aspect of the nwk anil thorax showing origin, course, and relations of the anomalous right subclavian artorj-. A window is cut into the aorta to show point of origin of anomalous vessel.

a, recurrent (inferior) laryngeal nerve

b, vagus nerve r, phrenic nerve

(/, inferior thyroid artery

c, sympathetic cord

/, anterior scalene muscle

(J, vertebral artery

h, transverse cervical artery

i, suprascapular artery

j, internal mammary artery

A', anomalous right subclavian artery

/, right common carotid artery

tn, trachea

H, left connnon carofi<l artery

o, left subclavian artery

p, superior vena cava

7, aorta

r, origin of anomalous right subclavian

artery .V, left bronchus /, pulmonary artery M, descentling th«»racic aorta c. heart

THE ANATOMUAl. RECORP, VOL. 8. NO. I

18

JAMES F. COBEY

the lieart-shapt'il space {tigs. 2 C and '2 D) wliioh is surrounded by the two embryonic aortae, so that the trachea comes to lie ventral to the anomalous subclavian artery when this is formed. The esophagus necessarily occupies the same position because, since tlie large blood vessels in the region develop around the fore-gut, the latter lies from the first in the loop ventral to the

A B c D

Fig. 2 Series of diagrams of the embryonic arterial arches for comparison of the normal with the abnormal development of the right subclavian artery. Dotted lines indicate points of absorption.

A Diagram representing primitive conditions.

B Diagram representing the usual development.

C Diagram showing the anomalous right subclavian artery (diagrams A, B, and C were modified from Piersol's Anatomy).

D An original diagram to illustrate subsequent change in position of anomalous right subclavian artery to condition described in text. The formation of the right vertebral artery should be noted also.

rs and /.s, right and left subclavian ar

te, internal carotid artery ec. external carotid artery cc, common carotid artery ma and Inn, right and left aortic arches

respectively i, iiuiominate arterj'

teries respectively ao, aorta

p, pulmonary artery r, vertebral artery X, |)()int of origin of anomalous right

subclavian arterv

dorsal aortae, and will therefore be ventral to an anomalous right subcla\ian artery as found in this cadaver, since the artery represents in part the original right dorsal aortic arch.

The exact extent and position of the absorption would appear to determine the point of origin of the right vertebral artery. That is, if the absorption of the right arch were not complete

ANOMALOUS RIGHT SUBCLAVIAN ARTERY 19

medially, as in figure 2 C, the unabsorbed portion would persist as the right vertebral artery which might thus arise from the aorta or even from the right common carotid artery. In my specimen the absorption was apparently complete, however, and the vertebral artery arose directly from the right .subclavian (fig. 2D).

The frequency with which such anomalies of the subcla\ian artery occur is represented in a report published by Arthur Thomson. This report is the result of the efforts of a committee of collective investigation for the Anatomical Society of Cireat Britain and Ireland. Five hundred cases in all were examined and, of these, five (1 per cent) presented the anomalous condition in which the right aortic arch persisted distally.

APPLICATION

It is within the range of possibility that the pressure exerted upon the right subclavian artery in its position dorsal to the trachea and esophagus, as reported above, might pnjduce symptoms resembling those of cervical rib. The natural inference would be that owing to pressure on the artery there would result a strong pulsation of the vessel and maybe trophic changes in the arm, forearm, and hand. Other symptoms and conditions associated with pressure on large blood vessels might be expected.

Anatomically the right arm appeared perfectly normal and further dissection of the body showed no other anomalies.

I am indebted to Prof. J. Parsons Schaeffer for suggestions and for reading the manuscript.

AN ANOMALOUS MUSCLE OF THE LEG: PEROXAEOCALCANEUS IXTERNUS.^

J. DOUGLAS PERKINS, Jr. University of Pennsylvania Medical School

THREE FIGURES

The cadaver presenting this anomal}' was that of a muscular negro of unknown age, and was one being used for ordinary dissection purposes in the Laboratory of Anatomy of the Uni\'ersity of Pennsylvania. The condition was found to be bilateral, the muscle being present in both the right and left legs.

It is a flat muscle arising partly by digitations from the flexor hallucis longus and partly from the lower half of the mesial surface of the fibula. Its fibers pass downward and inward into a tendon at its internal border. The tendon courses dowTiward and forward under the ligamentum laciniatum and over the sustentaculum tali to be inserted into the periosteum, and also into a tubercle at the distal internal surface of the calcaneus, just superior and lateral to the tendon of the flexor hallucis longus. At its origin it overlies the flexor hallucis longus; lower down the tendon enters the same compartment with that of the flexor hallucis longus, occupying a position superior and lateral to the latter.

The nerve supply could not be worked out as it had I urn destroyed before the writer took up the dis.section. but it probably came from the same muscular branch as that which supplied the flexor hallucis longus, that is, from the nen'us tibialis.

The blood supply is eff"ectod by means of a branch of the artoria peronaea.

The action is to assist in extension of the caqnis and ver>slightly to aid in supination.

' From the Laboratory of .\n;itoiuy of tlu« University of Pennsylvania.

21

22 J. DOUGLAS PEKKINS

Associated witli tliis muscle, there were found several other anomalies in the plantar rep;ion.

The tendon of the flexor hallucis longus broke up into two slij)s. the extra one later dixidiiifj; into two. which went to the second and third digits. At the lateral side of the distal forking, the lumbrical of the fifth digit took origin.

The insertion of the quadrat us plant ae divided and surrounded the branch of the flexor digitorum longus to the fifth digit.

A very slender slip of tendon connected the tendons of the fiexor digitorum brevis and the flexor digitorum longus of the fifth digit.

As far as the writer has been able to determine, this anomaly was first reported by Alexander ]\Iacalister,- who gave the muscle its name. He describes it as follows:

Peroneo-calcaneus ihternus is a .small muscle which .... seems to resemble the tensor oi the synovial membrane of the ankle of Henle and Linhart, .... it arises below the flexor hallucis longus from an oljlicjue line on the back of the fibula behind the external malleolus, passes over the back of the sustentaculum tali, in the groove with the flexor hallucis to be inserted into a tubercle of the os calsis. This muscle. I have elsewhere referred to ^s the probable homotype.of the pronator quadratus.

M. Auvray reports later, in 1896 r-^

Muscle surnumeraire de la region profomle posterieure de In jambe. Faisceau p^roneo calca^en interne. Macalister a d^crit sous ce nom im 'petit faisfcau' se detachant audessous du flechis.seur propre du gros orteil de la face posterieure du penjiie et venant se terminer sur le tubercle du calcaneum. Jc reporte un fait double de cette anomalie musculaire, rencontre sur Ic meme sujet. Dans mon cas, il ne s'agit pas d'un petit 'faisceau' conune le dit I'autcHir precedent, mais de deux veritables muscles nettement distincts des muscles voisins.

Sur la jambe gauche le muscle est represents dans ses deux tiers supSrieurs par un corps charnu situS au-de.ssous et en dehors du long flSchisseur propre du gros orteil. Les fibres viennent converger obli

Transactions of the Royal Irish Academy (1872); vol. 25, Science, part 1. p. 12.5. A<l<iitional observations on muscular anomalies in human anatomy, Alexan<ier .Macalister.

'Bulletins «le le Socic^'tt Anatomique de Paris, TT Annee, (189G), 5me Serie, Tome 10., F. 7, p. 22.3-224. Anomalies musculaires et nerveuses. M. .\uvray.

AN AXOMALOrS MUSCLE OF THE LEG

23

^ ^

Kiij. 1. .Superficial dissection. F.L.D., M. rt«'x«)r »Iigitoruin longus; /'.L., M. peron.'ieiis longus; F.L.H.. M. flexor halhuis lonpiis; T.A.. M. tibialis antirus; P.H., M. poronaeus brevis; P.C.I., M. peronaeo-caleanous internus: P.I.T.F.L.. Lig. Malleoli lateralis postcrius; I.A.L., Lig. lariniatum.

Fig. 2 Deep <lissection. Sm., insertion of M. semimembranosus: P.T.A., A. tibialis i)osterior; r..l...\. jxTonaea; P.T.\., branch of N. tibialis.^., origin of the M. flexor halluois Umgus cut away from the fibula; F.L.P., M. flexor digitorum longus; F.L.H., M. flexor hallucis longus; I., intenligitation brtwwn M. flexor halluois longus an«l the M. peronaeo-<'aleaneus internus; P.C.I., M. |>eronacoealcaneus internus; 7.1., M. tibialis antirus; In., insertion of M. pfronaeo-calcaneus internus; /'./,.. M. peroneaus longtis; IS., septum musrulare p«tstrriu.<".

IM

J. DOUGL.\S PERKINS

Fig. 3 Plantar rogion. F.L.I)., M. Hoxor difiitoruiii longiis; P.C.I. , M. peronaco-calcanoous intcrnus; F.L.H ., M. flexor halliicis longus; Ah.H ., M. Abductor halluois; L^'., M. lutnhricalis of oth digit; F.A., M. (luadratvis plantac; F.B.H., M. flexor hallucis brevis; F.P J., first plantar intcrosseus muscle; P.L., M. peronaeus longus; L.P, Lig't., long plantar ligament; F.B.D., M. flexor digitorum brevis.

quement vers un tendon (lui s'otcnd sur toutc la longueur tlu muscle. Co tendon passe sur la face interne du calcaneinn dans la memc goutticire fjue le long flechisseur projjre, et vient s'inserer dans le fond de la gouttiere ealcaiK'-ene interne sous la chair carr<'>e.

Sur la jamlx' droite, il s'agit d'un muscle qui est le plus volumineux des muscles de la couche profonde de ce cotd. II s'ins6re par son corps charnu sur la face post(rieure du peron^' dans toute son etendue, entrc Ics in

AN ANOMALOUS MUSCLE OF THE LEG 25

sertions des peroniers lateraux en dehors et du long fl^chisseur propre en dedans. Les fibres charnues convergent obliqu(ment vers un tendon qui occupe la face posterieore du muscle, s'en detache en arriere de la tibio-tarsienne pour passer dans la meme coulisse tendineuse que le long flechisseur propre, et s'inserer comme du cote oppos^ au fond de la gouttiere calcaneenne sous la chair carree.

A. F. Le Double^ speaks of it as follows :

Par deux faisceaux fixes, I'un au tibia, I'autre a I'aponevrose qui recouvre le flechisseur tibial et aboutissant a un tendon commun qui se divise, a la plante du pied, en deux branches dont la plus interne va sf perdre sur le tendon du flechisseur du gros orteil. Ces faisceaux ont ete decrits sous le nom de M. peroneo calcaneus internus par M. Macalister qui les a decouverts. M. Auvray en signale receniinent un nouveau cas 1896.

The following mention is made of it by L. Testut:^

Faisceau peroneo-calcaneeus interne (Peroneo-oalcaneus internus de Macalister). C'est un petit faisceau, decrit par Macalister, se detachant, au-dessous du flechisseur propre du gros orteil. de la face jxjsterieure du perone et venant se terminer sur le tulxTcule de calcaneuni. Macalister, qui I'a decrit le ])remier, le rapproche du fai.-^ceau tenseur de la synoviale du cou-de-pied. Xe pourrait-on pas le rapprocher. avec autant de raison, du long accessoire des flechisseurs.

The specimen was examined by Dr. Cleorge A. Piersol. who stated that he regarded the peroneo-calcaneus internus as an accessor^' long flexor.

With the idea in view that a pr()t()tyj)c might exist among the mammalia, the writer made a search of the literature concerning the myology of extremities, and was unable to find mention of a similar muscle represented in any group.

The author wishes to express his gratitude to Dr. CJeorge A. Piersol, Professor of Anatomy, and to Dr. (Jeorge Fetterojf. Assistant Professor of Anatomy, untier whose direction the work has been done; also to J. Percy Moore. Ph.D.. and Merkel H. Jacobs, Ph.D., for their assistance.

Trjiiti^ dvn variations <iu .syst«^mr tmisrtilairo I'hominc (1897), Tome "J, p. 404, Le Doublf.

' Trait i" dos variations du syst»Mm> niusculairc <lo Ihoinino ot »lo lour signification au point <lr vut* (le I'.anthropoloKio zooloni(|ui\ I'aris. IS'.)7, L. Ti^stut.

ANATOMY AXD DISSECTOR IX ABSTRACT, Stewart L. McCurdy, A.M., M.D., professor of anatomy and surgery. University of Pittsburgh; orthopedic surgeon Presbyterian an<l Columbia Hosjjitals; SI illustrations, 372 pages, fourth edition, $1.00. Mediral Abstract Publishing Company, Pittsburgh, Pa. DISEASE AXD ITS CAUSES, W. T. Councilman, A.M., M.D., LL.D.. professor of pathology, Harvard University; 254 pages including index,$.50 net. Henry Holt and Company, Xew York, and Williams and Xorgate, London.

A -M.VXU.AL FOR WRITERS; covering the needs of authors for information on rules of writing and i)ractices in printing, John Matthews Manly, Head of the Department of English, The University of Chicago, and John .\rthur Powell, of the University of Chicago Press; 225 pages including index, 1913, SI. 25. The University of Chicago Press, Chicago, 111.

MODERX PROBLEMS OF BIOLOGY, lectures delivered at the University of Jena, December, 1012, Charles Sedgwick Minot. LL.D., D. SC; fifty-three illustrations, 124 pages, 1913, $1.25 net. P. Blakiston's Son and Company. Philadelphia, Pa. CUXXIXGHAM'S TEXT-BOOK OF AXATOMY, edited by Arthur Robinson, M.D., F.R.C.S., professor of anatomy, Universitj^ of Edinburgh; 1124 figures from original drawings, ()37 of which are printed in colors, and two plates, 1596 pages including index, 1913, .?(!.. ")0 net. cloth, .$7.50 one-half Morocco. William Wood and Company, Xew York.

DIE AXATO.MIE DES MEXSCHEX. mit Hinweisen auf die iirztliche Praxis. Erste Abteilung: Einleitung, Allgcmeine CJewebelehre, (Jrundziige der Entwickelungslehre. Friedrich Merkel, professor in Gottingen. 251 .\bbildungen im Text. 255 pages including index, 1913, S marks. V'erlag von J. F. Bcrgmann, Wiesbaden.

SOME IDEAS IX LABORATORY EQUIPMENT

R. -M. STRONG Hull Zoological Laboratory, The University of Chicago

FOUR FIGURES

In a previous paper' I described some electrical heating apparatus for paraffin baths in use at the University of Chicago. Recently, some improvements have been made, and I discuss these and some other laboratory apparatus, in this article.

In the paper just mentioned, I described a new form of thermostat designed for the Lillie type of paraffin bath. Though this thermostat runs for a number of weeks ^^^thout attention, it occasionally becomes necessary to clean it, and one improvement consi-sts in making the mounting more simple for the needle which makes and breaks the current to the 'cut out.' In the new form, the tube ])ranch to be cleaned may be made accessible by removing only one screw which has a milled head as may be seen in figure 1. The tulx' branch is cleaned by a swab of cotton wrapped around the roughened end of a slender rod and dipjied in nitric acid. In case the cotton slips off the rod and becomes ])ack<Ml in tin- tuln*. another rod \nth a barbetl point is used to remove it.

Another improvement consists inomittingthe flanges at the t()j)s of the two branches of the glass tube. It was found that the preparation of these flanges often involves, even in the hands of a skilled workman, a slight contraction of the inside (hameter of the tube branch at its top which prevents a perfect fitting for the adjusting-screw plug. If the latter does not completely close the tube branch at all points, mercury slips up above it and interferes seriously with tlu^ accuracy of tinthermostat.

The moimting of a ]>araffin ])ath recently installcMl in the z(M>logical laboratories of The Tniversity of Chicago is shown in figure 2. It is constructed of angle iron 39 mm. wide on the side: ami it is KKS cm. high at the bottom of the }>araffin bath. A trough for dripping paraffin will l)e noticed in the shelf. It increases in depth from lo mm. at the left end to 'M) mm. at tlu> right, and it is 1.5 mm. \\$$U\ This paraffin bath was obtained from tiie Spencer I^>ns ($$mi)any. and it is .">0 cm. wide. 64 cm. high, and ;^9 cm. dee]). It will be noticed that the cross section

' H. M. Strong. Electrical heating of par.affin hnth.<. Anat. H<x'., vol. 7, no. 1, January, VM'.i, pp. O-IO; (> toxt figures.

28

It. M. STRONG

Binding post

-Lock-nul

Binding post

Fig. 1 From ])h()t()f!;rapli of iniprov('<l vippor portion of thormostat

area of the mounting is a few iiichos wntlor and (Iccjicr tliaii tliat of the bath, for the sjikc of stal)ility. The sHdinj? door was made as hirge as possible to furnish easy access to tlic electrical st(n'e inside.

'I'he i)ositions of the thermostat ;uid of the automatic switch, described in my j^revious i)ai)er, are indicated in figure 2. The switch box should ordinarily be at the opposite end of the bath from that shown in figure 2.

LABORATORY EQUIPMENT

29

— Tne'rrioilcii

^-"e^

Fig. 2 From photograph showing mounting of paraffin l);ith with parts of electrical heating ai)paratus in view.

A box for wasliiiiji; niiero.'^<,-{)])t' slidc."^ !.•< shown in Hpiirc 3. While writing this paper, I wa.s informed that .^imihir hoxes have been used elsewhere, but the idea may not l)e familiar to many workers. I have used this box with satisfaction for .several years. It is eonstrueted of eorrugated. galvanized iron, and its dimensions are as follows: greater diameter 7;} inches, inner i-hamber ")J inclu's. This leaves a space just wide enough for a 1 by :\ inch slide. The outsid(« wall is two inches high, and that of the inner chamber is Ij inches liigh. The Im^x is placed

30

R. M. STFtONG

FIk- 3 From photograph of box for washing microscope slides. Fig. 4 From photograph of apparatus for washing material in bottles or dishes and also for the bo.\ shown in figure 3.

uiidcr ;i tap as in fi^;ur(' 4, and water flows out over the top of the inner clianihcr into the slide chaml)er and from there out over the outer edge. A gentle circulation of water is thus i)rovided in all parts of the slide chamber, which I testetl by making the water densely turbid with a few drops of fuchsin. In the course of a very few minutes, all traces of the

LABORATORY EQUIPMENT 31

stain disappeared from the slide chamber even witli a rather gentle fall of water into the inner chamber. It is important to have the box in a horizontal position. It will be noticerl in fig. '4 that labels at the upper end of the slide are not touched by the water.

Apparatus for washing histologically fixed tissues is shown in figure 4. This stands on a shelf above a sink, and the box is 82 cm. long, 5 cm. high, and 30 cm. wide. A .series of small taps are provided, and all may be kept running by water at very moderate pressure, which enters at the right. Reducing T's lead to brass pet cocks and branched taps. At the left is seen the wash box which appears in figure 2. The pipe is plugged at the left of the tube which stands over the wasli box. It is at once apparent that a number of bottles or jars of material may be washed simultaneously, an arrangement which is useful \nth cla.s.ses in histolog}'. An outlet of ample capacity, at the outer left hand corner, empties the box effectively.

iC(Hitinued)

ANNALS OF SURGERY: ANAESTHESIA NUMBER, Vol. 58, No. 6, December, 1913, A monthlj^ review of surgical science and practice, edited by Lewis Stephen Pilcher, M.D., LL.D., of New York, with the collaboration of J. William White, M.D., LL.D., of Philadelphia, Sir William Macewcn, M.D., LL.D., of Glasgow and Sir W. Wat.son Cheyne, C.B., F.R.S., of London; 986 pages including inde.x in vol. 58, $5.(X) a year in United States, single number$.51). J. B. Lippincott Company, Philadeli)hia, Pa.

DIE BIOLOGISGHEN (IRUNDLAGEN DER SEKUNDAREN GESCHLECHTSCHARAKTERE, von Dr. Julius Tandler, o.o. Professor der Anatomic an der Wiener Univcrsitiit, und Dr. Siegfried Grosz, Privatdozent ftir Dermatologie und Syphilidologie an der Wiener Universitat. 23 text figures, 169 pages including index, 1913, 8 marks unbound and 8.80 marks bound. Verlag von Julius Springer. Berlin.

beitra(;e zur frage nach ber beziehung zwisghen klinischem verlauf und anatomischem refund bei nerven- und

GEISTESKRANKHEITEN, Bearbeitet und Herausgegeben von Franz Nissl, Heidelberg. Erster Band, Heft 1, 34 figures, 91 pages, 1913, 2.40 marks. Verlag von Julius Springer, Berlin.

ZEITSCRIFT FUR ANGEWANDTE ANATOMIE UND KONSTITUTIONSLEHRE, herausgegeben unter Mitwirkung von A. Freiherrn v. Eiselsberg, Wien, A. Kolisko, Wien, F. Martius, Rostock, von J. Tandler, Wien, Erster Band, Erstes Heft (Ausgegeben am 21 Juni 1913), 96 pages (Preis des Bandes M. 28). Verlag von Julius Springer, Berlin.

ANATOMIE DES ZENTRAIA'EHVENSYSTEMS. Siebzehnter,, der Sonderausgabe, Sechster Bericht, entlialtond die Leistungen und Forschung.sergebnisse, in den Jahren 1911 und 1912, von Prof. Dr. L. Edinger, in Frankfurt a.M., und Prof. Dr. A. Wallenberg, in Danzig, 115 j)ages including index, 1913, 6marks. A. Marcus und E. Webers Verlag, Bonn.

13

THE ARTIFICIAL PRODUCTION OF EYE ABNORMALITIES IN THE CHICK EMBRYO

CHARLES R. STOCKARD

Analomical Lahuralory, Cornell Medical College, New York City

TWO PLATES

During the springs oi 11)11 and 1912 a series of experiments were conducted on hens' eggs aiming towards a definite modification of development so as to produce typical defects. A large number of eggs was used and numerous methods of treatment with ^'arious chemical stimuli were em})loyed. The results, however, ha\'e not been of a definite nature, nevertheless they do indicate a decided tendency on the part of the developing central nervous system to respond to certain classes of stimuli in rather typical fashions. The responses are not in any sense specific for a given treatment but the same rather definite response may be obtained by a number of methods. This statement applies equally to other ex]:)eriments on the artificial i)roduction of ilefinite defects in the embryo. The earlier \iew that these defects were specific responses to the given chemical substance em])loyed as has been advocated by Herbst,' Hertwig, O.- the writer' and others is no doubt erroneous.

The important fact, howe\er. is that a certain definite response on the part of the devol()]Miig organism may be consistontly ol>tained after carefully adjustetl treatments witli a large number of different substances. Since the response is the same in each

' Herbst, C. Expoiinientolk' rnt(>rsuchunRoii, u. s. \v., Zcitschr. f. wissenst-h. Zool., 4, 189'J; Mitt. :i. d. Znol. St:u. zu Noapol, 1S'»3: Arch. f. Kntw-Mech. 4. I*<«16.

- Hertwig, (). Urniund und S|)in:i bifida. Eiiif vorgloichpntlo inorphologisrhe tcratologisclie Studio an iiiis.spebildotrii Frosclioiorn. .\rrhiv f. Mikr. .\nat. Bd. 30, ISOi: Die RaiiiunikraiikluMt tierisclior KiMtnzollon. Ein Boitrag ziir cxporimoiitellen Zmiguiigs- uud Vcrerbungslehrc. .-Vrohiv f. Mikr. .\nat. Bd. 77, Abt. -2, 1011.

' Stockard, C. R. The artificial production of cyolopian monsters: The "Magnesium embryo."' Jour. E\pr. Zool., (i, 1009.

33

THE .\N.\TOXIICAL KECORn, VOL. S, NO. '.' FEnnUAIlY, I'.M4

34 CHARLES 1{. STOCK A HI)

case it is vciy i)r()biibk' tluil the sul)stiiuc('s lh()U}i;li widely different act similarly on the embrj^onic organism, for example, in certain cases they may ser\'e simply to lower the developmental metabolism and thus prevent or arrest the formation of ]mrtirnlar structures.

The hen's egg readily lends itself to chemical and mechanical ex])eriments and has been largely employed in ex])erimental teratology. It has long been known that by running the incubator at too high or too low a temjjerature or by reducing aeriation by varnishing the shell one is able to obtain a most varied gnni]) of monsters. P^er^ has used a great num))or of methods to produce monster chick embiyos. In 1899 he treated eggs with alcohol fumes before incubation and found that the fumes penetrated the shell and produced \'arious abnormalities in the embrj'os. Fere^ also repeated Preyer's^ experiment of removing the egg from the shell and allowing it to develop in glass dishes. Pre3er was only able to keep the eggs under observation in this manner for two or three days, while Fere devised a l^etter means of ventilation and succeeded in keeping the eggs alive for six days. Many of the embrj^os developing out of the shell showed abnormalities. Fere's reports merely record the experiments and mention the t^^^es of monsters obtained but no detailed or systematic study was undertaken and his exi)eriments have generally passed unnoticed. One must, however, api^reciate the rather ingenious and various methods of treatment which Fer6 employed.

The experiments to l)e briefly described in the present communication are presented in order to show that the central nervous system and the eyes of the chick embryo become affected in a manner closel}' similar to that which I have recorded for the fish embry'os when treated with alcohol, ether and other substances.^

V6r(', Ch. Influence du repos, sur les cffets de I'exposition priSalable :iux vapours d'alcool avant I'incubation flc I'couf dc poule. Compt. rend. Soc. do hiol. .51, IS'Ht.

F<5r<5, C'h. Rernarqucs sur I'inrubation dcs oeufs de poule privds de leur coquillc. Conipt. rend. Hoc. de hiol. .52, 19f)0. Preyer, W. PhysioloRie sp^^ciale de Tenibryon. Trad, franc, p. 16, 1887. ^ Stockard, C. R. The influence of alcohol and other anesthetics on embryonic development. Am. Jour. Anat., 10, 1910.

ARTIFICIAL PRODUCTION EYE ABNORMALITIES 35

Hens' eggs were exposed for different lengths of time to the fumes of alcohol and ether. The eggs used in the experiments had been laid for only two or three days. Shallow dishes were arranged with a wire screen bottom beneath which absorbant cotton soaked with 95 per cent alcohol was placed. Eggs were placed upon the wire screen and the dishes covered and left standing at the room temperature. During the two years several hundred eggs were treated in this manner.

After the eggs have been exposed to the fumes for a short while the shell becomes covered with moisture, the condensed alcohol vapour and this -vapour penetrates the shell. The eggs were exposed for from twenty minutes up to thirty hours at room temperature. The shortest exposure that gave effects was three hours and forty-five minutes, though in many cases an exposure of as long as eight hours was non-effective. Exposures of from fourteen to twenty hours gave the best results. In these cases almost every embrj^o was abnormal yet most of them were able to continue development for several days at least. Exposures of twenty- three hours or more were usually fatal, the eggs failing to develop after being put into the incubator.

The chief point to consider in the amount of exposure is the temperature. When the temperature is high evaporation is more rapid and more alcohol enters the egg in a given time.

If eggs are placed in the incubator immediately after the treatment liquid oozes out of the pores in the shell on account of the slight expansion of the egg contents as the temjierature rises. A certain amount of the alcohol is no doul^t lost by this ])rocess. It is better, therefore, to allow the eggs to remain at room temperature for several hours after being removed from the fume dishes and before being placed in the incubator. Ford found that eggs put into the incubator immediately after treatment with alcohol fumes were not so decidedly affected as those treated for the same length of time but not subjected to the raised temperature until several hours after the treatment.

In other cases eggs were exposed to the alc(^hol fumes while in the incubator. Weak alcohol solutions were place<l below the egg tray and (>vaporat(Ml slowly. This treatment was also

36 CHARLES U. STOCKARD

fontiiiuecl for difToroiit loti^tlis of tinio aiul in many cases gave more decided effects than those ol)tainod l)y the treatments before incubation.

Ether fumes were also employed in the aijove manner. These fumes induce the same general types of de\'elopmental abnf)rmalities though they are more decided in action than alcohol fumes and kill the embr^'os nmch more readily.

Several injection methods were used and a number of substances were injected into the egg but the results were indefinite and often negative. In many cases the injection was a failure in that it either coagulated the albumen in the -region, or injured the egg so that it did not develop.

Following effective treatments with the fiunes of alcohol or ether the embryos were found to be small and behind the control in their rate of development. The abnormalities most abundant were of a general nature, in some cases the entire body of the embryo was absent while the area vasculosa was present containing blood islands and embrj^onic vessels. Other cases showed small embryos with the brain portion of the neural tube poorly developed. The cu'culation in many of the embrj'os was slow and sluggish and in such cases hydramnious conditions were present and the blood sinuses were also distended.

A number of the embiyos showed various abnormal eye conditions and these are the defects of particiUar interest since exactly similar abnormalities have been gotten in abundance when developing fish eggs are subjected to the actions of ether and alcohol. In several experiments embiyos occurred with small poorly formed eyes which closely resembled the minute defective eyes most commonly found in alcoholized fish embryos.

A few t>']oical cyclo]iean conditions were obtained showing different degrees of the defect. However, never more than three or four per cent of the embryos showed cyclopia even in the most successful experiments and in most instances cyclopia did not occur at all. Nevertheless, it is of importance to find that these treatments do occasionally induce the same variety of defects in the chick as was so abundant in many of the fish experiments.

ARTIFICIAL PRODUCTION EYE ABNORMALITIES 37

The monster monophthalmicum asymmetricum, that is, an individual with one eye of the normal pair perfectly de\'eloped and the other eye either absent or defec'ti\e to a marked degree, was commonly seen in the different groups of embrj'os, plates 1 and 2. This condition was more often found than cyclopia, yet it also was not as abundant as in fish embrj'os developing in solutions of alcohol or ether.

The failure to obtain definite defects in large numbers in the chick embryos is no doubt due to the fact that the amount of treatment is nmch more difficult to regulate than in such an egg as that of the fish. The great variation in the size of hens' eggs, the amount of albumen as well as yolk, the thickness of the shell, etc., makes it almost impossible to treat a number of eggs to the same degree. The treatment must of course be delicately balanced in order to obtain such typical defects as cyclopia and monophthalmica since they only occur as responses to a certain injur}' or arrest at a critical developmental stageIt has also been found in a series of experiments which is being conducted to test the effects of alcohol and ether on the stnicture of the offspring from guinea-]iigs that a completely eyeless young animal was produced and the nervous systems of almost all the offspring show some defects due to the treatment."*

During the winter of 1912 one of the incubators in the laboratory was placed in a room into which a ventilation system opened. The same system communicated with rooms in the chemical laboratory and fumes conveyed by the ventilator although rarelxnoticeable in odor were sufficient to injure the de\-elo]ung chicks. Many of the embryos thed during early stages. Tlie eggs were being used in tissue culture experiments l)v Dr. Hurnnvs and were usually o])ened after ha\ing de\elo])ed for alxmt twelve to eighteen days. Several of these large chicks were found to have only one lateral eye. They were similar to the early enihr>-os formed iii the abo\e (^x])eriments and were :v^ymmetrical mouo])htluilini(' monsters identical with those I have descrilie<l in

Stockivrd, C. 1\. Tlu' oflfoct on tlu> DfTsprinj; of intoxii'.itinR the male parent iiui the transmission of the defects to suhsoquont generations. Am. Naturalist, vol. 47, 1013.

38 PHAHLES M. STfUKARD

fish embn'os. Pli()t{)g;ra]ihs of three of thes© large chick embryos are figured in ])hites 1 and 2, since tli(\v ilhistrate the defect far better than the young three and four day twisted enibrj'os. The fiunes injured the eggs and caused the same t\'pes of devel()])mental arrests or supression as are obtained with the other sul)stances discussed above. After tlie incul)ator was removed from tliis room tlie eggs in it develoj^jcd in a perfectly normal manner.

These stnictiiral deformities and their ex])erimental production are recorded to enii)hasize the general nature of such defects and their wide occurrence among different tjq^es of embryos when treated with anj' substance which tends to arrest de\'elopment or lower their develo]miental rate and vigor. Elsewhere^ I have attempted to show how all abnormalities such as these eye structures may be explained merely as developmental arrests. Thus their wide occurrence in spite of their typical appearance.

PLATE 1

EXPLANATION OF FIGURES

Tlirec views of an asyininetrical one-eyed cliick monster wliich occurred in Dr. Burrow's incubator. The ui)|)er photograph shows tlie c\'eless side, a small nodule of skin in the orbital depression represents an abortive eye-lid formation. The lower left figure represents the opposite side with a perfect ej'e, the fully developed lids are closed. The lower riglit figure giving a dorsal view of the head emphasizes the general asymmetry due to the absence of the one eye. The beak is i)ermanently crossed since the upper jaw is forced to incline towards the eyeless side while the lower jaw remains in a normal position. It is thus impossible to dose the beak as all the figures show.

Ani. Joiirii. Anal., vol. 15, no. 3, 1913.

ARTIFICIAL PRODUCTION EYE ABNORMALITIES

CHARLES B. STOrKARD

PLATE 1

PLATE 2

EXPLANATION OF FIGURES

Two Other specimens of monster monophthalmicum asymmetricum. The huge eye of the embryo chick is seen on one side of the head while the other side is eyeless. Both of these embrj-os also show the twisted upper jaw and the permanentlj' open condition of the tnouth.

40

ARTIFICUL PRODUCTION EYE ABNORMALITIES

CHARLES B. STOCKARD

PLATE 2

41

A CASE OF PATENCY OF THE PERICARDIU.M AND ITS E.MBRYOLOGICAL SIGXIFK "AXCE

R. A. McGARRY

Department of Anatomy, University of Michigan

ONE FIGURE

During the winter of 1913 there was found in our laboratory an infrequent malformation of the pericardium in which there existed a large foramen, connecting the pericardial sac with the left pleural sac. Besides this condition there also occurred other anomahes of the coelomic derivatives, which if correctly interpreted, point back to an earl}- disturbance in the development of the general coelomic cavity. On account of the rarity of this condition, and on account of its broad embrj'ological significance, it was thought that the following report would not be out of place.

Briefly, the history of the case is as follows: ^Male, sixty-five years old; family history not obtained. After being in the Xewberry State Hospital for eleven 3'ears, suffering from tenninal dementia, the patient died with sjTnptoms of gastritis. Death occurred in 1913. During his residence at the hospital no s^^nptoms were obser\pd which would point to the condition wo are describing.

On examination of the Ixxly during the jirocess of dissection the rare condition was found of a large j^leuro-pericardial foramen. In addition to this there was also found a group of peritoneal disturbances; namely, a ventral hernia, left inguinal hernia, tendency to double femoral hernia, ami malposition of the colon. They will be described in that order.

The opening iiotwoen the pericardial and pleural sacs appeared as an opening from 7 to S cm. in diameter. The edge was free throughout its course, which extended from above the pulmo 43

44

n. A. Mc'CAHRV

iKiry Mi-tiMV. tlicnce over the root of the luiifi;. From tlicre it ari'luHl sliglitly forward, followiufi llic j:;roove l)ctwo(Mi tlio systoniic aiul puliuonary aortao. At the junction of the i)ulnionary artery with the rifi;ht ventricle the fold turned downward and backward, then upwaid to tenninate hack of the left atrium. Tiio free od.u;c continued laterally to the left, fonnins the left

I"i|iurc 1. Left |)lcural cavity viewed from tlieloft side, witli the left luiitt removerl. The larne foramen in the mediastinal jileura, in front of the root of the left luiiK opens direeti}' into the jjcricardial sae, exposing the heart; /, areh of aorta an<l large vessels; 2, pulmonary aorta; 3, left aurieular appendage; 4, root of left lung; 5, left phrenic nerve appearing through the left mediastinal pleura; 0, diaphragmatic pleura.

parietal layer of the pericardium, and to the ri^ht, forming:; the right co.>^tal pleiu'a. Through the opening could be seen the j)ulmonary artery and left auriculai' ai)))eii(lage, as sjiown in figure 1. The left phrenic nerve pass(>d between the two layers of the anterior edge of the foramen. Aside from the large opening in it, the pericardium was normal. There were no signs of adhesions or other disea»se except for a few adhesions over the apices

PATENCY OF PERICARDIUM 45

of the lungs. The upper lobe of both rij^ht and left lungs was partially di\'ided in each case, by a fissure from 1 to 2 cm. deep. Nothing abnormal was found regarding the diaphragm.

On examination of the peritoneum there was found a small ventral hernia, 1 cm. from the median line midway between the umbilicus and xiphoid cartilage. It pierced the transversalis fascia, both layers of the rectus sheath and the rectus muscle, appearing beneath the skin. The opening was 1 cm. in diameter. Through the opening protruded a tag-like appendage which appeared to be made up of a portion of the falsifonii ligament of the liver. A small vein and artery passed into it from the internal mammary \'essels. The left inguinal hernia was a very large oblique hernia extending down to the })ottom of the scrotum. It contained a large fold of the great omentum. In the region of both femoral rings there were distinct short funnelshaped pockets of the peritoneum extending into the femoral canals.

The malposition of the colon was determined by the abnormal disposition of its peritoneal reflections. The peritoneal covering was more com])lete than usual. Thus the caecum and part of the ascending colon were completely surrounded, and were suspended free in the cavity by a mesentery. The ascending colon was flexed ventrall.y and upward upon itself so that the caecum was lying above the right lobe of the liver. The vermiform appendix, 10 cm. long, was found beneath the junction of the sixth costochondral articulation, at the level of the xiphoid cartilage of the sternum. It passed down medially between the caecum and ascending loop of the sigmoid. The sigmoid colon formed a large looj) with a broad mesentery. The upper limb of the flexure extended oblifiuely upward across the umbilical and hypogastric i-egions into the right iiypochondrium. where it, together with the caecum, caused a marked depression uj^on the anterior surface of the liv(M-. The flexure turned here and the lower limb passed downward and i)ackward through the right hypochondrium, and from thence downward into the true pelvis, having formed a loop about 1(> indues long. ]\ was supported throughout its whole liMigtli l)y a mesentery. The great omen

40 K. A. McGAKHV

(uni was iiiurli onlarji;e(l and formed, as has been mentioned, the contents of the left inguinal liernal sac.

On examination of the Hterature I have been able to find eighteen cases of defective jiericardium. Three of these were found in foetuses and the remainder in adults. I have been able to examine the original articles of nine of these cases. Of the remaining nine, five were found in descriptions given by other writers, while the last four could not be utilized as the descriptions and references were either incomplete or the source unaxailable. The nine cases, the accounts of which I have had access to, are as follows:

Raillie (1788) reported a condition in a male of forty, in which the heart was found to lie free in the left pleural cavity. The mediastinum consisted of two laminae of pleura, inclined to the right side of the chest. Both laminae were connected throughout their extent by the intervention of a cellular membrane. This passed over the vena cava about 1 inch above the auricle. The heart was involved in the reflection of the pericardium, which became its immediate covering. This covering was very thin. The left phrenic nerve ran between the two laminae almost immediately under the sternum.

Curling ('39) reported a case in which, upon opening the chest, the heart was found completely exposed, lying loose in the cavity of the left pleural sac. There was no a])pearance of any j)ericar(jiuiii covering the heart. The only indication of a pericardium was a reflected fold which covered the pulmonary \-essels on the right side. The fold on the right side, close to the diaphragm, presented a small serous pouch with defined margin inferiorly and into which the appendix of the auricle i)rotruded. The anomaly was discovered in a male of forty-six.

Haly ('oOj reported a case of malformation of the j)ericardium in a male aged fifty-two. The malformation was discovered during a postmortem. The heart and left lung were were found to be in the left pleural sac. The heart was in close contact with the hmg, but connected in no way with the (iiai)iiragm. The membrane forming the common sac constituted the pleura of the lung ill one case, and the pericanliuni in llie oth(>r. The mem

PATENCY OF PERICARDIUM 47

brane continued in the horizontal direction, after leaving the sternum lined the ribs on the left side, covering the outer and posterior surfaces of the lung. On its inner surface it was reflected at the root of the lung, directly upon the pulmonary veins, thence to the right pleura. The left lung was described as being covered by a false membrane. The phrenic nerve pas.sed in front of the arch of the aorta to reach the septum between the two pleural sacs.

Bristowe ('54) reports a peculiar pericardium found in a male of twenty-eight. The heart was much enlarged. The heart and left lung were both contained in the left pleural cavity. The lower part of the lobe of the left lung was firmly attached to the anterior surface of the left side of the heart. A fold of membrane existed at the upper right side of the heart. It commenced at the pulmonary artery, passed over the aorta and vena cava, descending to the diaphragm. From this point it was lost in the root of the left lung. The fold consisted of fibrous tissue covered on either side by pleura. It was widest at the right auricle, where it was about 1 inch in depth. The fold was adherent to the heart in several places. The right phrenic nerve took its normal course, but the left passed down between the layers of the membrane, about one-half inch from its edge.

Powell ('68) reported a case in which a foramen connecting the pericardium and left pleura was found. The communication was situated above, and anterior to the root of the lung. It was small and oval in shape, being less than 1 inch in diameter. There were no adhesions, and the pleura in general was very thin. The left lung was found collapsed, the pleura containing a little fluid. The pericardium contained some air and a little fluid, the heart being compressed backward. To all appearances the o})ening was a congenital one.

Bjornstrom ('71) reported an anomaly which occurred in a female of forty. Only about one-third of the right side of the heart was covered with jiericardium. The remainder lay free in the left jileural sac in direct contact with the lung. A large foramen coimected the pericardial and left pleural sacs. Only that poitioii of the parii^tal pericardiuni was found which formed

48 U. A. McCAKliY

the wall hotwocii tlio rifjlit lun^ aiui hoart. The portion which was hack of the ri^iit auricio wont over into the visceral leaf and snrrounded tlie iieart on the right side; from here it passed on to tlie sternum, where it continued as the left pleura.

Prunrose (,'01) reported a patency of the i)ericardiuni occurring in a male of sixty. An opening existed between the pericardium and left pleura whicli was al)out 3 inches in diameter. The structures wliicii sliowed through tlie foi'amen were as follows: aorta, from its appearance to about 1 inch beyond origin of the left subclavian artery; pulmonary aorta, from its origin to its bifurcation; and the left auricular appendage. No indications of adhesions were present. A number of other anomalies were present which involved principally the genito-urinary system.

Keith (,'07) leported two cases of malformation of the pericardium. The first case of deficiency of the pericardium was found in an anence])halic full-term child. The opening, just anterior to the root of the left lung, was about 1 inch in diameter, and through which the left auricular appendage protruded. It had a round smooth margin. The phrenic ner\-e descended in the anterior free edge of the foramen.

The other case occurred in a foetus, the subject of numerous malformations. It presented a large deficiency on the left side. Upon remo\al of the sternum a strong fi))rous membrane was found behind it, upon which the phrenic nerve descended. This proved to l)e the j)ericardium. wliich descended and divided, the left margin passing in front of and below the left lung. Turning back at the lower margin, it api)eared as a fold extending up from the diaphragm. The greater part of the left pleural cavity being occupied by the liver, stomach and spleen.

The five cases to which reference has been made by other writers included one in which the heart was found h^ing free in the left pleural cavity, dcxoid of pericardium, that was reported in the Philosophical Transactions, London, 1740, and referred to by Jiailli(! in 1788. The same author refers to shnilar cases recorded by C'olumbus, Bartliolinus, and Littre, in which no details were mentioned. Peacock ('68) , in his work on the malformations of the human heart, refers to a case by M. Breschet ('26), in whicli the

PATENCY OF PERICARDIUM 49

absence of the pericardium occurred in a male of twenty-eight. Another case was reported by Hud in 1848. He also mentioned a specimen in the St. Thomas Museum, London. Peacock mentions a case found by himself in a man of seventy-five. He, however, did not describe it. There were three cases of malformation of the pericardium for which I have not been able to get the original articles, the titles of which are given in the references at the end of this paper.

Not including my own case, we may summarize the hterature of the malformation of the pericardium as follows : (a) two cases of supposed complete absence of the pericardium ; (b) seven cases of incomplete pericardium, which is represented by a small fold of tissue along the posterior wall; (c) three other cases of incomplete pericardium, in which existed a distinct opening between the left pleural sac and pericardial sac, varying in diameter from less than one-half inch to over 3 inches; in six cases the condition was not definitely described, the only mention made being of both heart and lung lying in the left pleural sac.

The only attempt by any of the writers to explain these cases on an embryological basis, was made by Keith. This writer attributed the patency to, an extension of the lung bud growing into and expanding the communication between the pericardium and pleura."

Peacock thought that the pericardium developed as a continuation of the fibrous sheath of the vessels of the heart, which spread out over the heart, and formed its sac. He considered the foramen as due to a failure of fusion of the membrane on the left side.

None of the previous writers directed their attentions to the related serous cavities, and no examination was reported, of the peritoneum and its appendages.

Before entering into the embryological significance of the malformations it may be well to give a brief review of our present knowledge of the development of the coelom. It was early shown by His that the body cavity in the early embryo is divided into the pericardial and trunk cavities. The comnmnication between these spaces is calhnl the parietal recess. The parietal

THE ANATOMICAL HECOnO, VOL. 8, NO. 2

50 R. A. McGARRY

portion originally contains the heart, and is destined to become the pericardial coeloni. A portion of the parietal recess forms the pleural cavity; it surrounds the lung bud throughout its development, and becomes the pleural coelom. In the remainder of the parietal recess the liver and stomach develop, but are later evaginated and become part of the abdominal coelom.

For our knowledge of the details of the separation of these cavities we are indebted to Mall. He showed that at about the end of the fifth week, while the body is yet kinked upon itself, the line of separation appears between the pericardial and pleural coeloms. This is due to a constriction of the walls along the ductus Cuvieri, which lies on a ridge of tissue encircling the canal of communication between the two cavities. This forms the beginning of the pulmonary ridge. This ridge appears as a small elevation, in the sagittal plane of the body, running from the lobe of the liver, along the dorsal wall of the ductus Cuvieri, to the dorsal attachment of the mesocardium. Lying in the sagittal plane of the body opposite the fourth and fifth cervical nerves it receives into its substance the phrenic nerve, which passes posterior to the ductus Cuvieri.

Soon the lung bud, which has heretofore hung free in the pleural coelom beneath the pulmonary ridge, grows outward against it and causes it to bulge. With the rotation of the liver towards the head the ridge is divided into two parts: (1) the cephalic which has included in it the phrenic nerve, and ductus Cuvieri, and which later becomes the plcuro-pericardial membrane; (2) the caudal portion, which remains at the caudal end of the septum transversum and liver, on the one hand, and the body wall on the other. It later forms the pleuro-peritoneal membrane.

The pulmonary ridges from their beginning to their separation into the plcuro-pericardial anil pleuro-peritoneal membranes appear as two ear-like projections from the septum transversum, oxtondifig alang the ductus Cuvieri. They appear in the sagittal plane of the body at right angles to the plane of the septum transversum. The growth of the pleuro-pericardial membrane in the direction of the head and the growth of the pleuro-peritoneal membrane caudally results in a widening of the dorsal projection

PATEN'CY OF PERICARDIUM 51

of the septum transversum. The lung burrows into this space throwing the pleuro-cardial membrane and phrenic nerve to its medial side. Up to this time there has been a mere slit where the pleuro-pericardial membrane comes in contact with the root of the lung. At the time of closure the small ridge or pleuro-pericardial membrane, is very insignificant, its extension being due to a rapid growth of the lung.

Brachet showed that the canal connecting the ca\'ities was only constricted by the ductus Cu\neri, its complete closure being due to an active growth of the anlage of the pleuro-pericardial membrane, which takes place at about this time. This completely separates the pericardial from the pleural caWties. Immediately after this the rotation of the liver and setum transversum takes place which changes the relation of the pleuro-pericardial membrane from parallel to right angles to it. By this time the pleuro-peritoneal membrane stretches across the body to the tips of the embryonic ribs, thus completely closing ofif the abdominal ca\'it3'. This also alters the position of the phrenic nerve.

With the steps of the development of the coelom in mind, we are in position to understand something of the manner of occurrence of defects in the pericardium and other coelomic derivatives. In my own case it is evident that there was a general involvement of the coelom. We are not accustomed to thinking of pathologic processes in the embr\'o limited to the developing coelom. but it is evident that such must exist. It is well known that the neural plate passes through a period when it is particularly sensitive to injury while the adjacent tissues are unaffected, and thus we have a group of pathological conditions, as anencephaly, spina bifida, etc., that date from this period. In a similar way it is reasonable to suppose that the cells lining the coelomic space, may at some period be particularly sensitive, and abnormal conditions occurring at thl** time, would result in disturbances, either an over production or an under production, of the serous derivatives. Thus we might naturally expect congenital hernias, gastroptosis, enteroptosis, and other abnormal conditions of the peritoneum, occurring at the same time with abnonnal conditions of

.)2 H. A. mc(;auky

the pericardium and jilcura. which coiuiition is well illustrated * in our case. The occurrence of a patent pericardium is one aspect of a general condition. It is possible also in our case that in the process of subdivision of the general coelomic spaces an undue proportion was constricted off by the lower limb of the pulmonary ridge, resulting in an over production of peritoneum, and an under production of thoracic serous membrane.

Those cases in which a foramen occurred, including the one found in our laboratory, between the pleura and pericardium seem to be explained by supposing that in the early development of the embrj'o, some slight injury occurred to the general coelom, which resulted in a lack of development of the pleuro-pericardial membrane. The membrane, which was to form the wall between the heart and lung failed to fuse with the root of the lung bud, and the pleuro-pericardial foramen resulted. This view is also supported by the position of the phrenic nerve.

The explanation given by Keith ('06), according to whom the foran>en was due to the presence of the lung which kept the communication between the pleural and pericardial cavities open, could hardly be the cause, as the lung bud forms subsequent to the development of the fold, which separates the cavities.

The case in which only a small portion of the supposed pericardium was found, existing as a ridge or fold at the base of the heart, seem to be readily explained. It at once suggests itself that the condition, with which we were dealing, was due to a less complete separation of the pleuro-pericardial membrane than occurred in those cases presenting a foramen. Thus the heart and lung would lie in a sac, which if it had separated, would have ff)rmed the pericardium and pleura, the fold or ridge of membrane existing at the base of the heart being the embrj'onic remains of the upper portion of the pulmonary ridge. The phrenic nerve in these cases was found under the sternum, probably never having been included in the substance of the pulmonary ridge.

Those cases in which a total absence of the pericardium was supposed to have occurred are explained as follows: The upj)er limb of the i)ulmonary ridge totally failed to develop. Tlie con

PATENCY OF PERICARDIUM 53

dition there is apparent. The heart and lung lie in one sac, which if correctly named would be pericardial, inasmuch as the left pleural sac had never become separated off. These cases must not be confused or connected with the cases described by Todd ('13) and others regarding the absence of the pleural sac in certain mammals. In those cases the pleural sacs were originally present, but in later life became obliterated.

The second case reported by Keith ('07) forms an interesting variation. Here the lung, heart and liver were found all occupying the same cavity. This condition must be explained by the involvement of both the pleuro-pericardial and pleuro-peritoneal membranes. As has been noted, the pericardial defects alwaj's are found on the left side. This apparently is associated with the asymmetry of the liver, and its rotation during the course of development, which would put a greater tension on the left pulmonary ridge, and predispose this to the defect.

Before concluding I wish to express my obligations to Professor Streeter at whose suggestion this report was undertaken.

CONCLUSIONS

1. Pericardial defects result from a disturbance occurring between the fifth and seventh weeks of embryonic life.

2. These defects always occur on the left side.

3. Other coelomic disturbances of the same period occur in the form of peritoneal abnormalities, such as congenital hernia, gastroptosis and other abnormal arrangements, and distributions of the peritoneum.

4. Congenital pericardial defects have not yet been clinically diagnosed and apparently produced no functional disturbance.

54 R. A. McGARRY

LITERATlllE CITED

liAiLLiE, M. 1793 Oil want of a i>cricar(lium in the human body. Tr. Soc. Imp Med. Chinirg. Knowledge, London, p. 1()12.

Baly, \V. 1850 Absence of pericardial sac, the heart lying in the cavity of the left pleura. Tr. Path. Soc. London, vol. 3, p. 60,

Br.\chet, a. 1897 Recherches sur I'eletion de la portion cephalique des cavitea pleuralcs ct sur Ic development dc la membrane pleuropericardique. Jour, de I'anat. et physiol., vol. 33.

Bjornstrom, F. 1871 Defect in pericardium. Upsala Larkereforenings Forhandlinger, p. 261.

Bristowe, J. S. 1854 Malformations of the pericardium. Tr. Path. Soc, Loudon, p. 109,

Chiari, H. 1880 Ueber einen Fall von fast vollstandigem defekte des Pericardium parietale. Wien. Med. Wachnschr, Bd. 30, p. 372.

Curling, T. B. 1839 Want of a pericardium. Tr. Med. Chir. Society, London, vol. 22, p. 222.

Gay, M. 1899 Di una speciale anomalia del pericardio. Lavori d. Cong. d. med. int., Roma, vol. 8, p. 437.

Hewsox, a. 1896 Absence of fibrous pericardium on left side. Proc. Assoc. Amer. Anat., Washington.

Keith, A. 1906 Partial deficiency of the pericardium. Jour. Anat. Physiol., vol. 6.

-Mall, F. P. 1901 On the development of the human diaphragm. Johns Hopkins Hosp. Bull., vol. 12.

1910 Die Entwicklung des Coeloms und des Zwerchfells. Handbuch d. Entwick. d. Menschen. Kcibel u. Mall., Leipzig, vol. 1, pp. 527-552.

Peacock 1868 Malformations of the human heart. London.

Powell, D. R. 1868 Deficiency in the pericardium. Tr. Patii. Soc, London, vol. 20, p. 99.

Primrose, E. J. 1901 Patency of -the pericardium, (ilasgow Med. Jour., vol. 56, p. 184.

Todd, T. W. 1913 Notes on the respiratory system of the elephant. Anat. Anz., Bd. 44.

THE PERCENTAGE OF WATER IN THE BRAIN OF THE SMOOTH DOG-FISH, MUSTELUS CANIS

GEORGE G. SCOTT

Department of Natural History, College of City of New York

Donaldson^ has shown that in the albino rat between birth and maturity the percentage of water in the brain diminishes from 87.8 per cent to 77.5 per cent. He calls attention to the fact generally known that the human brain at birth contains a greater percentage of water than at maturity and from the investigations of Weisbach and Koch he obtains as the percentage of water in the human encephalon the following: birth, 88.3 per cent; two years, 81.1 per cent; five years, 79.2 per cent; twentyfive years (mature), 77.0 per cent. Donaldson further says:

We reach the interesting conclusion that probably in all mammals we shall find approximate^ the same range in the percentage of water between birth and maturity and that the loss of water in them occurs in the same manner but that the time required for each successive step is determined by the intensity of the growth process characteristic for each species.

The present author in 1910 had obtained the percentage of water in the brain of a few smooth dog-fish but at the suggestion of Dr. Donaldson, has collected further data on this subject in order to see whether the above law holds true for the elasmobranchs, which occupy a place at the base of the vertebrate ladder.

The author collected the following data at the Biological Laboratory of the United States Bureau of Fisheries at Woods Hole, Massachusetts. He is greatly indebted to the Bureau of Fisheries for the material and facilities furnished him.

The data are not as complete as they might be but since the\' illustrate a difference between the elasmobranchs and the mam

Donaldson, H. II., Jour. Corap. Neur., vol. 20. no. 2, p. Ill), April, 11)10. 55

56

GEORGE G. SCOTT

mals, this paper is presented at this time. The percentage of water in tlie brain of ninety-seven smooth dog-fi&li-, ]\Iustelus canis, was obtained. These were obtained from the laboratory trap in Buzzard's Bay and the brain tissue was removed on the same da}- that the fishes were brought into the laboratory. In

TABLE 1

Showing the percentage of water in the brain of the dog-fish, Mustelus canis, of increasing body length. Sex, male.

NUIIBSR

LENGTH

BBAIN WKIGBT

WATBB IN BRAIN

NX7MBBB

LENGTH

BRAIN WEIGHT

WATER IN BRAIN

cm.

grams

per cent

cm.

grams

per cent

1

39

1.39

77

27

70

2.60

79

2

42

1.42

77

28

70

2.61

79

3

42

1.48

77

29

72

3.17

81

4

44

1.41

77

30

74

3.36

78

5

45.

1.51

79

31

75

3.18

78

6

52

1.98

79

32

75

3.20

78

7

55

2.08

79

33

75

3.20

78

8

56

2.24

74

34

76

3.14

78

9

57

2.26

80

35

77

3. 52

79

10

60

2.24

80

36

77

3.55

80

11

60

2.33

77

37

77

5.77

85

12

61

2.35

77

38

79

3.44

74

13

64

2.50

82

39

79

3.41

78

14

65

2.13

74

40

80

3.45

75

16

65

2.67

79

41

80

3.33

80

16

65

2.80

79

42

81

3.78

80

17

65

2.61

79

43

81

4.16

81

18

66

2.59

80

44

82

3.38

79

19

67

2.79

81

45

82

3.25

74

20

67

2.91

79

46

82

3.65

78

21

67

3.35

81

47

82

3.65

78

22

69

2.94

80

48

83

3.47

80

23

69

3.17

79

49

85

3.60

80

24

70

2.77

75

50

90

4.06

81

25

70

3.05

77

51

91

3.89

79

26

70

2.94

77

eaoli ease the following technique was employed. The sex, length and weight of each specimen was first recorded, then the brain case was opened. The olfactory tracts were severed close to the forebrain, a transverse cut made at the posterior margin of the fourth ventricle, the cranial nerves severed and the brain

WATER IN BRAIN OF DOG-FISH

57

carefully placed on clean filter paper. A longitudinal cut was then made through the brain and each half very carefully turned over on the filter paper until no further cerebral fluid was absorbed. The brain tissue was then placed in a watch cry.-tal and its weight determined. It was next placed in a desiccator over sulphuric acid. The desiccator was made a partial vacuum.

TABLE 2

Showing the percentage of water in the brain of the smooth dog-fish, Mustelus canis, of increasing body length. Sex, female.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

BRAIN WEIGHT

42 44 45 56 60 62 62 62 62 62 62 62 66 66 67 69 69 70 71 72 74 74 75

grama

1.48 1.33 1.47 2.20 2.26 2.40 2.48 2.42 2.24 2.53 2.73 2.92 2.65 3.20 2.73 2.99 2.55 3.33 2.92 3.25 3.22 3.31 3.49

WATER IN BRAIN

per cent

78 78 78 77 79 78 80 80 77 78 79 80 76 81 79 79 79 76

76 SI

78

BRAIN WEIGHT

cm.

grams

24

75

3.27

25

75

3.35

26

75

3 .02

27

75

3.&3

28

77

3.48

29

77

3.88

30

79

3.58

31

79

3.51

32

80

3.24

33

81

3.29

34

81

3.27

35

82

2.85

36

82

3. .56

37

82

3.50

38

89

3.82

39

90

4.22

40

90

3.74

41

92

4. -26

42

96

4.11

43

97

4. 28

44

99

4. .58

4.5

104

4.4.5

46

105

4.49

WATER IK BR.UN

per cent 76 79 83 79 82 84 75 80 75 81 84 80 79

SO 80

78

79 7T 76

78

The brain tissue was then dried to a constant weight and the percentage of water computed. Since in this problem the percentage of water only was desired, the same great care to get e\'ery trace of brain tissue was not as necessary as in the ease where the exact weight of the brain at various ages was to be investigated.

58

GEORGE G. SCOTT

The chanpe in tlio wein;lit of the brain of INIustelus eanis and of increasing body weight has been carefully worked out by Kellicott ('08) whose paper will be referred to later. Tables 1 to 5 show the results obtained. Tables 1 and 2 show the percentage of water in the brain of smooth dog-fishes of increasing body

TABLE 3

Showing the percentage of water

in the brain of the smooth dog-fish, Mustelus canis, oj

increasing body weight. Sex,

male.

nvuamK wbiobt

BHAIN WXIOBT

WATEB IN BRAIN

NUUBBB

WBIOBT

BBAIN WEIGHT

WATEB IN B|tAIN

granu

gramt

,per cent

grama

grit'n*

per cent

1 218

1.39

77

27

1057

3.05

77

2 264

1.48

77

28

1057

3.55

80

3 280

1.42

77

29

1057

2.80

79

4

311

1.51

79

30

1088

5.77

85

5

326

1.41

78

31

1120

2.79

81

6

420

1.98

79

32

1244

3.20

78

7

451

2.08

79

33

1306

3.18

78

8

560

2.26

80

34

1337

3.20

78

9 560

2.61

79

35

1368

3.14

78

10 575

2.24

74

36

1399

3.36

78

11 ' 591

2.33

77

37

1399

4.16

81

12 653

2.35

77

38

1462

3.44

74

13 1 669

2.24

80

39

1462

3.38

.79

14 684

2.91

79

40

1462

3.33

80

15 715

2.50

82

41

1555

3.41

78

16 746

2.13

74

42

1586

3.78

80

17 746

2.67

79

43

1648

2.60

80

18

746

3.35

81

44

1679

3.25

74

19

775

3.71

81 45

1679

3.52

79

20 840

3.06

80 I 46

1773

3.45

76

21 ' 933

2.59

80

47

1773

3.47

80

22 ' 933

3.17

79

48

1990

4.06

81

23 995

2.77

75

49

2021

3.66

78

24 995

2.94

77

50

2053

3.66

77

25 ! 995

2.60

79

51

2379

3.89

79

26 1 1042

1

2.94

80

length, males and females respectively. Tables 3 and 4 show the percentage of water in the brain of fishes arranged according to increasing body weight instead of length.

Donaldson found that at different body weights the male brain contains a greater percentage of water than the female

WATER IN BRAIN OF DOG-FISH

59

brain in the case of the albino rat. Xot only is this sex difference true of the percentage of water, but as is commonly known, the male brain actually weighs more than the female brain in relation to the weight of the body. Kellicott,^ on the other hand, found that in the smooth dog-fish there was no sex difference as to total brain weight. He says, It is not possible to distinguish

T.IBLE 4

Shomng the percentage of water in the brain of the dog-fish, Mustelits canis, of increasing body weight. Sex, Female.

NUMBER

WEIGHT

BBAIN WEIGHT

WATER

NUMBER

WEIGHT

BBAIN WEIGHT

WATER

grams

grams

per cent

grams

grams

per cent

1

280

1.48

78

24

1151

3.48

82

2

295

1.33

78

25

1182

3.31

79

3

342

1.47

78

26

1213

2.73

79

4

529

2.20

77

27

1244

3.49

78

5

560

2.92

80

28

1368

3-27

76

6

622

2.73

79

29

1368

3.50

78

7

637

2.26

79

30

1368

3.51

80

8

653

2.42

80

31

1493

3.22

76

9

684

2.40

78

32

1550

3.58

75

10

715

3.20

81

33

1617

3.88

84

11

746

2. "24

77

34

1679

3.29

81

12

746

2.55

80

35

1679

2.85

80

13

762

2.48

80

36

1835

3.24

75

14

809

2.53

78

37

1928

3.56

79

15

871

2.65

76

38

2364

3.74

80

16

871

3.35

79

39

2395

3.82

78

17

902

3.33

76

40

2.5S1

4.22

80

18

964

2.99

79

41

2846

4.0.S

77

19

1026

2.92

77 j

42

2892

4.26

78

20

1057

'2.55

79 1

43

3297

4 11

77

21

1057

3.02

83

44

3390

4.45

76

22

1057

3.63

79

45

3452

4.28

79

23

1151

3.25

77

46

4198

4.49 1

1

78

between the sexes with respect to brain weight." But what is the condition as regards the percentage of water? The average percentage of water in the brain of the forty-six females recorded here is 78.6 per cent, while that of the fifty-one males is 78.5 per cent. There is no sex difference in Mustelus canis as far as the

Kellicott, W. E., .\m. Jour. Auat., vol. 8, no. 4, p. 207, December, 190S.

60

GEORGE G. SCOTT

percentage content of water in the brain tissue goes. This is in agreement with the result obtained by Kellicott.

But what is the condition as regards the percentage of water in the brain at different ages?

Since there are no sex differences we can group together the males and females. Nothing is known of the exact age of the dog-fish but in general they increase in length and weight as they grow older. Kellicott, following the methods of Moenkhaus and Fulton with teleosts, has roughly estimated the ages as shown in table o.

TABLE 5

Now since we are ascertaining the relation of the percentage of water in the brain to the age and since age is measured by length and weight, it is necessary to distribute the specimens concerning which we have records, according to the above schedule. Applying Kellicott's criterion we have table 6.

TABLE 6

(A) LENGTH MAI.E + FKMA.I.E

(B) WEIGHT HALE + FEMALE

1 year ^

2 years.

3 years.

4 years. .') years.

6 + 3 =

22 + 15 =

20 + 19 =

3 + 4 =

+ .5 =

9

37

39

7

5

Total, 97

7 + 4 = 11 22 + 18 = 40 18 + 14 = 32

4+3=7

0+7=7

Total, 97

We thus see that we have about the same distribution by length as by weight. It will be noted that the medium sized

WATER IN BRAIN OF DOG-FISH

61

are most numerous. The average percentages of water in the brains of the various groups just given are shown in table 7.

TABLE 7

LENGTH

WEIGHT

AVEBAOE

1 year

per cent 77.8 78.5 78.9 79.4 77.4

per cent per cent 77.9 77 8

2 years

78.7 78 6

3 vears

78.8 78 8

4 years

79.0 79 2

5 years

77.9 77 7

,

As far as the above results go, there is no great decrease in the percentage of water with increasing age. This appears contrary to what Donaldson has found in the case of the albino rat. There he found a decrease of water of 10 per cent between birth and maturity.

I was able to secure seventeen specimens of young Squalus acanthias, the spiny dog-fish. These fish, as may be seen in table 8, are all under one year of age.

TABLE 8 Shotving sex, length, weight, brain weight and percentage of water in the brain of

young Squalus acanthias

()2 GEORGE G. SCOTT

Moroover. eight females and two males from the standpoint of Icngtli would be regarded as reeentl}' born, according to the age criterion given above. But when we look at the weights we find these to be much greater than what is called for, namely, 75 grams. And yet it must be remembered tliat we are now discussing a species other than that for which Kellicott constructed his age table.

The average percentage of water in the brain of these seventeen Squalus acanthias is 81.4 per cent. On the whole this group is smaller in length and weight and so younger than the smooth dog-fishes, ^Mustelus canis. There is some slight indication then of a small decrease in the percentage of water in the brain between birth and the first year. This should not be emphasized, however, since we are dealing with two different species of fishes. Kellicott has shown that during the period of which we have data, the brain of Alustelus has increased from about 1.5 grams in weight to about 4.0 grams. During this time also it has decreased from about 0.6 per cent to 0.2 per cent of the total body weight. And yet we have seen that the percentage of water in the brain has remained quite constant. How can we account for this?

Mammals are characterized by determinate growth. As soon as maturity is reached the organs ha\'e reached their size limit. For example, the bones increase in length no further. On the other hand, fishes have indeterminate growth, that is, they grow as long as they live. As far as the brain is concerned, in the case of mammals growth is very rapid during the first few months. C)n the other hand, in fishes the brain grows steadily as long as the animal lives. As Kellicott says, After birth (smooth dogfish) the brain weight increases rapidly but at a slightly diminishing rate. Among the large individuals the diminution is much slower but is continued during life. Donaldson shows that the diminution in percentage of water is most rapid during the first thirty days of the albino rat's life, that is, when the central nervous system is growing most actively. Amphibians also possess indeterminate growtli. Tigerstedt,' reviewing the work of

» Tigcratedt, Textbook of hmnan physiology, 1906, p. .574.

WATER IN BRAEST OF DOG-FISH 63

Birge, says that he counted the motor cells in the spinal cord and nerve fibres in the anterior spinal roots in frogs of different sizes" and convinced himself that both either multiply from preexisting nerve elements or from other elements throughout life." He found "unmistakable relation between the weight of the animal and the number of cells and fibres. On the average for each 1 gram increase in weight, 52 motor fibres had been added."

The most significant difference between the rat and the dogfish, as far as our present discussion is concerned, is the postbirth condition of the two. The rat is born helpless, blind and cannot move about for some time. On the other hand, the dogfish is born, free — swimming, active and apparently mature with the exception of the reproductive system. Donaldson shows a correlation between the period of rapidly forming ner\'e cells and the percentage of water in the brain. Very possibly the dog-fish has a greater percentage of mature nerve cells at birth than the rat. We should expect a smaller percentage of water than in the case of the rat. This is borne out by the conditions in the young spiny dog-fishes discussed above. If the discoveries of Birge are correct and applj^ equally well to the dog-fishes, as we have considerable reason to believe, then the continued constancy in the percentage of water in the elasmobranch brain is due to the multiplication of new nerve cells and fibres keeping pace with the growth of the brain in other respects.

According to Donaldson's table, about seven-tenths of the percentage decrease in water takes place in the first one-eighth of the rat's life, between birth and maturity. There is a decrease of only three-tenths during the remaining se\'en-eighths of this maturing period, that is, it occurs during the first tliirty out of the total two hundred and forty days. The period of greatest loss in water is that during which profound neurological changes take place. May not these changes Uike place in the dog-fish in utero? The two cases make a strong argument for considering the change in water content of the central nervous system to be correlate<i with the growth intensity of tliis system. And that in the dog

64 GEORGE G. SCOTT

fish the gre<atest change takes jDlace in-utero, while in the rat and man it is extra-utero. The collection of data from the brains of embryonic stages is necessary to decide this hypothesis.

A NOTE ON THE PRESENCE OF A MUSCULUS CLEIDO ATLANTICUS IN THE DOMESTIC CAT (FELIS

DOMESTICA)

RANDOLPH WEST

Laboratory of Comparative Anatomy, Princeton University

ONE FIGURE

So far as is known to the writer the musculus cleido-atlanticus (Gruber)^ has never been described as occurring in the cat, nor in any other mammal in which the clavicle is rudimentary. In order to avoid confusion, the nomenclature used by Reighard and Jennings- will be followed throughout this paper, and, in addition, the term cleido-atlanticus will be used to designate a muscle, hitherto not described in the cat, arising from the atlas and inserting into the clavicle.

Both the m. levator scapulae ventralis (levator claviculae) which arises from the atlas and inserts into the metacromion, and the m. cleido-atlanticus have been described as anomalies in man by Testut,^ under the common name of the m. cleido omo-transversaire and bj- Le Double,^ under the conunon name of the m. omo-trachelien. The m. cleido-atlanticus is found alone in the anthropoid apes, as well as in Nycticibus tardigradus and Cynocephalus anubis. while it is present in connection with the m. levator scapulae ventralis in the orang. Always one and occasionally both of these muscles occur regularly in all vertebrates except the fishes, birds and man. In some vertebrates these muscles may ha\e origins from the basi-occipit^il and from the posterior cervical vertebrae in addition to the atlantal origin. For a fuller account of the comparative anatomy

' Testut, Les anomalies musculaires chez rhoinme. 18S4, p. 97. ^ Reighard and Jennings, Anatomy of the cat. 1901.

' Le Double, Variations du sj'steme musonlaire de I'homme. 1S97. T 1, p. 235.

65

THE ANATOMICAL RECORD, VOL. S, NO. 2

66

RANDOLPH WEST

of the m. cleido-atlanticus the reader is referred to the articles of Testut and Le Double cited above.

The ni. cleito-atlanticus (4, fig. 1) was found hi one adult female cat and was present on both sides of the body. Out of some four hundred cats dissected in the laboratory this is the

Fig. 1 1, M. clavotrapczius; 2, M. sternomastoideus; 5, M. cleidomastoideus; 4, M. cleido-atlanticus; 5, M. levator scapulae ventralis (levator claviculae); 6, M. occipitoscapularis (levator scapulae dorsalis); 7, M. splenius; 8. M. levator scapulae; 9, M. supraspinatus; 10, \I. acromiotrapezius; U, M. acromiodeltoidcus; 12, M. clavobrachialis.

first one in which this muscle has been observed. It arises in commf)n with the m. levator scapulae ventralis (5) from the posterior portion of the transverse process of the atlas. After about 0.5 cm. the two muscles separate, and the m. levator scapulae ventralis inserts into the metacromion. The m. cleido

A MUSCULUS CLEIDO-ATLANTICUS IN THE CAT 67

atlanticus inserts into the lateral third of the clav-icle and into the raphe which lies lateral to the clavicle, between the m. clavotrapezius (1) and the m. clavobrachialis {12). About 1.75 cm. before its insertion it is joined on its medial border by the m. cleidomastoideus (3), which inserts into the medial two-thirds of the clavicle. The m. cleido-atlanticus is an elongated muscle, somewhat flattened at the clavicular end. It is about 6 cm. in length, 0.25 cm. broad at the atlas, 1 cm. broad at the clavicle and 0.5 cm. thick in the cat here described. The innervation is from the ventral ramus of the third cer\4cal nerv^e which also supplies the m. levator scapulae ventralis, the m. cleidomastoideus, the m. stemomastoideus {2) and several other muscles of this region.

68 EDITORIAL EXTRACTS

ANTI-\lVISECTION MORALS

It makes no diflference to an anti-vivisectionist how hard a blow she receives from the facts. She comes up smiling just the same. Dr. Keen, the famous Philadelphia surgeon, exposed recently a number of the latest lies, and Mrs. Henderson, vicepresident of the .Vmerican Ant i- Vivisection Society, came back with the most cheerful and unmoved assertion of her own opinion and interpretation against overwhelming evidence. Then comes along Dr. Crile. Mrs. Henderson had quoted Dr. Crile's book on "Surgical Shock," sajdng that it "repeatedly describes experiments followed by the words 'no anesthesia.' " Dr. Crile has studied his own book faithfully, and cannot discover any such words. We have not yet noticed ]\Irs. Henderson's answer to Dr. Crile, but feel sure that it will be just as cheerful as her answer to Dr. Keen. Harper's Weekly, January 24, 1914.

«

SCIENCE AND MERCY

The Anti-vivisectionists have been putting out a circular in Philadelphia, with the statement that Dr. George W. Crile made experiments on one hundred and forty-eight dogs "in an endeavor to learn the extent of the agon}- that can be inflicted on a living animal." Do the kind-hearted women who are backing this movement believe that Dr. Crile did anything of the sort? When they leave out all mention of anaesthesia, do they do it by accident? Surgeons until recently thought that when a patient was unconscious they could tear loose adhesions and manipulate tissues roughly without doing mischief. Crile's experiments were to determine whether this view was correct. He found that it was not; that serious injury could be caused by shock even when there was no consciousness. Reahzing the difference between psychic shock, which is prevented by anaesthesia, and traumatic shock, which is not prevented by anaesthesia, is an important step ahead, which has already resulted in a lower death rate and a shorter time for recovery. Crile, like other men of science who are called monsters of cruelty by these kind but ignorant sentimentalists, is the apostle of gentleness. Harper'.H Weekly, January 31, 1914.

PROCEEDINGS OF THE AMERICAX ASSOCIATION OF ANATOMISTS

THIRTIETH SESSION

At the University of Pennsylvania, Philadelphia, Pa., December 29,

30, and 31, 1913

]\IoxDAY, December 29, 10.30 a.m.

The thirtieth session of the American Association of .Inatomists was called to order by President Ross. G. Harrison, who appointed the following committees:

Committee on Nominations: J. Plaj-fair ^McMurrich, chairman; Robert R. Bensley, Henry ]\IcE. Knower.

Auditing Committee; Harry B. Ferris, chairman; Burton D. Alyers.

Tuesday, December 30, 12.00 m. Associatiox business MEETING, President Ross G. Harrison presiding.

The Secretary reported that the minutes of the Twenty-Ninth Session were printed in full in The Anatomical Record, volume 7, number 3, pages 91 to 98, and asked whether the Association desired to have the minutes read as printed. On motion, seconded and carried, the minutes of the Twenty-Ninth Session were approved by the Association as printed in The Anatomical Record.

Harry B. Ferris reported for the Auditing Committee as follows: The undersigned Auditing Committee has examined the accounts of Dr. G. Carl Huber, Secretary-Treasurer of the American Association of Anatomists and finds same to be correct with proper \ouchers for expenditures and l)ank balance on Deceml>er 20 of .'?213.03. (Signed) Harry B. Feiuus, Burton D. ]Myers; Philadelphia. December 30, 1913.

m

70 AMERICAN ASSOCIATION OF ANATOMISTS

The Treasurer made the following report for the year 1913 :

Halancc on hand December 29, 1912 $318 .08 Receipts from dues, 1913 131o .39 Total deposits for 1913$1033 .47 $1033 .47 Expenditures for 1913: Expenses of Secretary -Treasurer, Cleveland Meeting$20.50

Postage 40.00

Printing ($11.90), typewriting ($8.75), envelopes ($2.50). ... 23.15 To 297 subscriptions to 1 volume of the American Journal of Anatomy and 1 volume of the Anatomical record @$4 .50. . $1336 .50 To exchange for foreign draft .29 Total$1420.44 $1420.44 Balance$213 .03

Balance on hand, deposited in the name of the American Association of Anatomists in the Farmers and Mechanics Bank, Ann Arbor, Michigan, December 26, 1913.

On motion of George S. Huntington the reports of the Auditing Committee and the Treasurer were accepted and adopted.

Tlie Committee on Nominations through its Chairman, J. Playfair McMurrich, placed before the Association the following names: President, G. Carl Iluber; Vice President, Frederic T. Lewis; Secretary-Treasurer, Charles R. Stockard. For members of the Executive Committee for term expiring in 1917, Warren H. Lewis and C. Judson Herrick.

On motion the Secretary was instructed to cast a ballot for the election of the above-named officers.

Moved by J. Playfair McMurrich, seconded by Robert R. Bonsley; That this Association accepts with regret the resignation of Dr. G. Carl Huber from the office of Secretary-Treasurer and desires to place on record its high appreciation of his services and its recognition of the prominent part he has taken in bringing the Association to its present prf)sporous condition and in advancing the cause of Anatomy on this conthient both by precept and example." Carried.

The Secretary presented the following names, recommended by the l^^xecutive Committee, for election to meml3ership in the American Association of Anatomists:

PROCEEDINGS 71

Edwin A. Baumgartner, Instructor in Anatomy, Universily of Minnesota.

Henry Bayon, Associate Professor of Anatomy, Tulane University.

Thomas H. Bryce, Professor of Anatomy, University of Glasgow.

Felix P. Chillingworth, Assistant Professor of Physiology and Pharmacology Tulane University.

Eleanor L. Clark, Research Worker, Johns Hopkins Medical School.

George W. Corner, Assistant in Anatomy, Johns Hopkins University.

Robert S. Cunningham, Johns Hopkins Medical School.

A. Campbell Geddes, Professor of Anatomy, McGill University, Montreal.

Stacy R. Guild, Instructor in Histology, Dept. Med. and Surg., University of Michigan.

G. V. Ariens Kappers, Director of the International Central Institute for Brain Research of Holland.

Howard S. Murphy, Professor of Anatomy and Histology, Ames, Iowa.

D. A. Rheinhart, Indiana University.

Arthur Robinson, Professor of Anatomj-, University of Edinburg.

Katherine Julia Scott, Johns Hopkins Medical School.

Paul G. Shipley, Assistant in Anatomy, Johns Hopkins University.

R. W. Shufeldt, Major Medical Corps, U.S.A. (Retired).

G. Elliott Smith, Professor of Anatomy, Victoria University, Manchester, England.

Perry G. Snow, Professor of Anatomy, University of Utah.

Johnso.v Symington, Professor of Anatomy, Queens University, Belfast, Ireland.

Arthur Thomson, Professor of Anatomy, University of Oxford, England.

J.\coB Thorkelson, Professor of Anatomy, College of Physicians and Surgeons Baltimore, Md.

R.\ndolph West, School of Medicine, Columbia University, New York City.

James Thomas Wilson, Professor of Anatomy, University of Sydney, Australia.

On motion of E. A. Spitzka, the Secretary was instructed to cast a ballot for the election of all the candidates proposed by the Executive Committee. Carried.

George S. Huntington proposed the following amendment to the Constitution. To substitute for the last sentence of Article II the following :

"These officers shall be elected by ballot at the annual meetuig of the Association, and theu' official terms shall conmience with the close of the Annual Mooting."

"At the annual mooting next procecUng an election the President shall name a Nominating Conmiittee of three members. This Committee shall make its nominations to the Secretary not less than two months before the annual mooting at which the election is to take ])laco. It shall ho the duty of the Secretary to mail the list to all members of the Association at least one month before the annual

72 AMERICAN' ASSOCIATION OF ANATOMISTS

meeting. Adtlitional nominations for 'duy office may be made in writing to the Secretarj' by any five members at any time previous to balloting."

This proi)os(>d anuMidment to the constitution becomes a matter of record for this meeting and will be acted upon in due form at the next annual meeting. (See Section 2, Article VII, of the Constitution, published in Anat. Record, \'^ol. 4.)

President Harrison announced that he had appointed J. Playfair Mc]\Iurrich to represent this association to meet with representatives from the American Society of Zoologists and the American Society of Naturalists for the purpose of formulating plans for the federation of these organizations with a view of obtaining coordination at the annual meetings.

The question of pul)lishing abstracts of papers presented at the meetings was discussed by Knower, Huntington, ]\IcMurrich, Huber and others. The following motion, presented by George S. Huntington, was seconded and carried: Moved that beginning with the next annual meeting members intending to present papers at such meeting be reciuired to furnish the Secretary with an abstract for publication in the Proceedings of the Association at the time of sending in the titles for inclusion in the official program of the meeting.

Henry McE. Knower moved that a committee of three be appointed from this Association for the purpose of standardizing the courses in biology required in premedical courses and leading to the stud}' of anatomy. Motion seconded by E. A. Spitzka, and carried. The President later announced as such Committee, Henry McE. Knower, Chairman; Frederic T. Lewis, Warren H. Lewis. On motion the business meeting adjourned.

At the conclusion of the scientific program on Wednesday the following business was presented:

C. Carl Hubor proposed the following amendment of Article \ I of the constitution: The first sentence of the article "The animal dues shall be $5.00" — it is proposed to amend to read "The annual dues shall be$7.00. This becomes a matter of record and will bo aftod upon at the next annual mooting (see Section 2, Article Wl of the Constitution).

PROCEEDINGS 73

On motion the Association tendered its sincere thanks and appreciation to Professor Piersol and the members of his staff, and the local committee, and to Provost Smith and other officials of the University of Pennsylvania for the very efficient arrangements made and for their hearty cooperation in furthering the success of this meeting.

G. Carl Huber,

Secretary-Treasurer of the Thirtieth Session of the American .\3s0clatl0n of Anatomists

The following Scientific Program was presented and is here recorded by abstracts or titles.

Monday, December 29, 10.30 a.m. to 12.30 p.m., President Ross G. Harrison, presiding.

1. The development of the lymphatic system in the trout} Charles F. W.

McClure, Princeton University.

My investigations on the development of the lymphatic system in fishes have been confined to the vessels of the head and phan,Tix. The fishes thus far studied include Amia calva, Lepidosteus osseus, Salmo Gairdneri (steelhead trout), Salmo irideus (rainbow trout) and Salvelinus fontinalis (brook trout). The vascular system of between 600 and 700 trout embryos has been injected and embryos studied both in transparent mounts and in sections. Forty-two reconstructions aft^r the method of Born have also been made of the arteries, veins and h-mphatics in the head and pharynx regions of Amia, Lepidosteus and the trout, which illustrate the development of the l>Tnphatic system from the time of first appearance, up to the establisliment of a condition, in which a continuous system of channels is present. Since the injection method ha,^ been employed in following the development of the lympiiatics in the trout, I will confine my remarks, for the most part, to the conditions met with in this form.

The injection method shows that the channel system (iumina) of the developing lymphatics, is not continuous at 'its inception with tliat of the veins, but is represented by a series of independent and discontinuous lymjih sacs or lymph spaces, which subsequently become confluent witii one anotlier and. at definite points, join \\\\\\ the veins, to form the continuous lym])hatic system of tlie adult. The ]>rinciple involved in tiie development of tiie l>'mphatic system tlierefore appears to be essentially the same as that met with in the yolk l)la.stoderm of vertebrates, where the continuous system of hunina of the blood-vascular plexus, is formed

' Rciul bcfoio Section I, of the Seventeenth International Congress of Medicine held in London in 1913.

74 AMERICAN ASSOCIATION OF ANATOMISTS

through the confluence of independent and discontinuous vascular spaces and the endothehum which hnes these spaces, is formed from cells which possess a local origin.

At the time when a continuous system of lymphatics is first met with in the trout embryo, they are represented, on each side of the body, by the following main vessels:

/. The lateral pharyngeal li/niphatic. This vessel occupies a superficial position in the lateral wall of the pharynx and forms the direct anterior continuation in this region of the lymphatic of the lateral line of trunk. The lateral pharyngeal lymphatic may communicate wnth the precardinal vein at the cardino-Cuvierian junction, in common ^\^th the l^inphatic of the lateral line of the trunk; with the precardinal vein near the caudal end of the otocyst or at both of these points. These points of communication ^^^th the veins may be single or multiple in character.

2. The subocitlar lymph sac. This is a relatively huge Ij-mph sac at this stage of development, which lies ventro-medial to the caudal half of each eye and drains into the veins, only through the lateral pharj'^ngeal IjTTiphatic, at the tjT^ical points of entry mentioned above.

3. The medial pharyngeal lymphatic. This vessel lies medial to and is more deeply situated than -the lateral pharyngeal lymphatic. It runs an oblique course, in a postero-anterior direction, from about the middle of the lateral pharyngeal lymphatic, with which it often communicates, to open into the precardinal vein just caudad of the point where the latter leaves the cranial cavity.

4. The precardinal or jugular lymphatics. These vessels develop along the line of the precardinal veins and drain into the lateral phar>nigcal IjTnphatic near the caudal end of the otocyst. In later stages the mesenteric lymphatics drain into the lateral pharyngeal lymphatic through this system of vessels.

At such a stage of tlevelopment as that just described, all of the abovementioned l\Tnphatics, including the subocular Ij'mph sacs, can be readily injected from the veins. Also, at this time, blood can and often dose pass from the veins into the l.vmphatics. In one special case, blood was observed to pass from the precardinal vein into the left lateral pharyngeal IvTnphatic of a living trout embryo and, after completely filling the left .subocular lymph .sac, to flow back almost immediately into the vein. The passage of blood from the veins into the lymphatics ceases after the veno-l>Tnphatic valves have been formed and observations made upon the living trout embryo, lead me to believe that the passage of blood into the lymphatics, before the valves are formed, is not of any functional significance in the economy of the vascular system, but is due rather to certain local hydrostatic conditions, possibly related to the intermittent flow of the lymph into the veins, as well as to the handling of the embryo under observation. Whatever the case may be, I am convinced that the l>Tnphatics of the trout embryo are not transformed veins.

The 8uf)ocular lymph sac can be observed in the living trout embryo almost from the time of its first appearance and, on account of the relatively large size it attains, is not paralleled by any other l>Tnph structure,

PROCEEDmOS 75

I know of, for convenience of observation and experiment. On account of its large size, the development of the subocular lymph sac is best followed in the steelhead trout (salmo Gairdneri), where it makes its first appearance in the embryo between the thirteenth and sixteenth days, depending upon the temperature of the water in which the embryos have been hatched. As far as I have been able to observe in the material at hand, the subocular K-mph sac makes its first appearance in the form of spaces or clefts in the mesenchyme which occur medial to the caudal end of the eye. These spaces finally become confluent to form at first a multilocular and then a single-chambered sac. For a period of from 5 to 7 days after its first appearance in the embryo, each subocular lymph sac serves as a local and independent reservoir for the reception and retention of lymph which it obtains from the head-region and which it retains, until the sac makes a connection with the lateral pharyngeal lymphatic, through which it then drains into the veins. Prior to the establishment of this connection, I have been unable to inject the subocular lymph sacs through the veins or the veins through the subocular sacs.

Subocular hnnph sacs are also found in the embryos of ganoids, but differ from those in the trout in that they drain directly into the veins, in an unmistakable manner, during a very limited period of embrj'onic development. They then become detached from the veins (12 mm. Amia and 14 mm. Lepidosteus) and, as far as I have been able to determine without the aid of injections, remain detached from the veins, as well as from the rest of the l\Tnphatic system, even in embryos of Amia which have attained a size of 40 mm. in length. The area drained by the subocular hmph sac in the trout, appears to be drained in the ganoids by a lymphatic, not present in the trout, which opens into the anterior end of the lateral pharyngeal lym]5hatic. Whether the subocular lymph sacs of ganoids, like the caudal lymph hearts of some birds, are only evanescent structures which are not carri^^d into th^^ adult. I am unable to state at the present writing. In" consideration of the supposed relationship which exists between the teleosts and the ganoids, it would not be surprising to find a stage of development hi which the subocular lymph sac of the trout, like that of the ganoids, drained temporarily into the veins. Such a stage, however, I have thus far been unable to find in any of my injected trout embryos.

Coincident ^\^th the develoi)ment and growth of the subocular lymph sacs in the trout, discontinuous and independent lymjih sacs or spaces are lieing formed, along the lines subsequently followed by the other main Ij'mph chamiels. These spaces or sacs never approach in size that of the subocular lym])h sacs, but like the latter. api)ear to serve :u*; indepemlent and temporary reservoirs for the reception of lymph, prior to the estal)lishnient of a comnumication between their lumina and that of the veuis. Those lymph sacs which lie contiguou>^ to the caudal end of the otocyst (otic lymjih .sac) ami to the carclina!-Cuvieri;m junction (cardino-( uvierian lymph sac), may establish a communication with the veins, which is imictically coinciilent ^^^th their first apix'arance in the mesenchyme and they are then capable of being injected.

70 AMERICAN ASSOCIATION OP^ ANATOMISTS

Those indei^onclent lymi)h sacs, however, which lie remote from those sacs or remote from tlie i)oints at wliich ])ennanent communications are estahhshed with the veins, camiot he injected from the veins, until after they have l)ecome confluent with lrmi)h sacs which lie o])posite to and communicate with the veins, at the specified points of communication which, as far as I know, are retainetl in the adult.

Ultimately, all of the discontinuous lymph spaces or sacs become confluent to form a continuous system of vessels. The rate, however, at which this confluence takes place is extremely variable, not only amonp; different embr^'os of the same age, but even ujion opposite sides of the same embryo. In one series of steelhead trout embryos, hatched at a temjjerature of about 10.5°C\, both sul)ocular lymph sacs, in the majority of the embryos examined, had established a coimection with the lateral i)har>nfieal iymjiliatic on the twenty second day after fertilization, and could be readily injected from the veins. In some of the embryos of this same series, however, this coimection had been established on one side of the body only and the lateral pharyngeal hTnphatic of the opposite side, extended and could be injected to a point near the subocular lymph sac, but did not connect with the same. Injection experiments have proved conclusively that the subocular l^-mph sacs do not grow caudad. It is through a centripetal confluence of the lymph sacs or lymjih spaces which lie in the course followed by the lateral pharyngeal lym})hatic, that the latter vessel is formed, before its connection with the subocular lymph sac is established.

2. The genetic relations of lymphatic and haemal vascular channels in the embryos of Am,niotes. Geo. S. Huntington, Columbia University, New York.

In certain regions in amniote embryos Ijonphatic vessels develop, during tlie early stages, primarily for the purpose of conveying r(>d blood cells formed in situ in the adjacent haemopoetic mesenchyme directly into the venous channels. Functionally these early lympiiatic vessels are e.s.sentially haemophoric. During the period of this functional activity they offer no morphological criteria differentiating them from the adjacent haemal channels. Much of the confusion of terms and of interpretation found in the records of the recent investigations into the development of the lym])hatic system is due to the misconception of the early functional ciiaracter of these priinitiv(^ lymjihatics. They have, (jwing to their blood cell contents, been da.ssed indiscriminately as venous tributaries or venous derivatives. In the course of further dev«l()i)m('nt these early haemopiioric lymjihatics may, after p(>rforming their })riinitive function, atrophy completely and disappear as comjxments of the definite lymphatic system, as in the case of the proximal portion of the primitive ulnar lymphatic of the mammal. In other regions the early haemophoric lymphatics, after conveying the developing blood cells to their destination within the lumen of th(> large veins, are retained as functional lym])hatic. components. The jugular lymj^hsacs (anterior lymph hearts) of mammalian, avian and reptilian em

PROCEEDINGS 77

bryos are examples of this condition. Also, as recently discovered by Miller, the avian thoracic duct. The development of the systemic lymphatics in embryos of the three amniote classes can be compared in the region of the main axial channels (thoracic ducts).

1. In the reptile (chelonia and lacertilia) the large adult periaortal lymphatic sinuses develop at first as small intercellular clefts in the spongy mesenchjnne surrounding the dorsal aortic arches and the median dorsal aorta. These spaces enlarge, approach each other, fuse and finally surround the aorta as a huge periarterial IjTnphatic sinus, with trabeculae in the interior, representing remnants of the original mesenchjTnal partitions between the components of the sac. This extensive periaortal lymphatic sinus of the reptiles represents the much reduced thoracic ducts of birds and mammals. It establishes secondary connections with the independently developed peripheral IjTnphatic channels, joins the jugular l3Tnphsacs, and through them attains its entry into the venous system.

P>om its earliest inception in intercellular mesenchymal spaces the reptilian periaortic sinus is at no point in relation to the venous system. It is closely applied to the dorsal aorta, but there are, at the site of its development, no large embrj'onal venous channels corresponding to the mammahan azygos (post- and supracardinal) trunks. Consequently the developing thoracic, or rather coelomic, Ijonphatic sinuses of the reptile never come into intimate genetic or topographical relations with axial veins.

Further, the axial periaortic mesenchj-me of the reptilian embryo is not the site of an active intraembryonic haemopoesis. Consequently, in strong contrast with the a\'ian type, the reptilian homologues of the thoracic ducts never become haemophoric.

2. The bird follows the general reptilian type of development, with the follo^^^ng important modifications:

The periaortal mesenchj-me of the chick is the site of a most active and abundant intraembryonic haemopoesis. IMasses of developing bloodcells (liffer(>ntiate as axial strands, the "mesenchymal chords" of Sala (1900), ventral to the aorta, directly from the indiflferent periaortic mesenchymal S3^ncytium. Subsequently the anlages of tiie thoracic ducts appear in this periaortic area as isolated intercellular mesench^Miial clefts and spaces. These spaces become confluent, receive the l)iood cells developed in the periaxial blood islands, convey them through the cliannels of the thoracic ducts to the jugular lymph sacs, and througii tiiem into the circulating venous stream. After this evacuation of their early blood contents the axial lymj^hatic channels are retained as the permanent avian thoracic ducts (Miller).

8. In the mammal, as shown by a number of recent inv(\stigations, the anlages of th(> thoracic ducts tleveloji as independent intercellular mesenchymal spaces surrovuuling the tem]iorary ventro-medial tributary plexus of the azygos veins. Subsequently these venous radicles, enveloped by the growing lymjihatic s{)aces, become detached from the azygos veins, atrophy, and are finally replaced topographicallif by the

78 AMERICAN ASSOCIATION OF ANATOMISTS

mammalian thoracic ducts. This type of lymphatic development has been described by McClure and mvs(>lf as the "I'xtra-intimal," because the lumen of the lymphatic anlage is always cclal of the intimal lining of the degeneratinp; vein, which the resulting lymphatic channel is destined to replace.

Hence each amniote class offers special and peculiar developmental conditions in this i)articular region. Differing at the first glance widely from each other, they all conform to a common genetic ground-plan, if the same is interpreted in terms of the relation of the first lymphatic anlage to the early periaxial development of blood cells. The reptilian embryo offers in this region the clearest and lea.st complicated illustration of the basic principle underlying all vi'rtebrate vasculogenesis in general and all vertebrate lymphatic development in particular, namely, the formation of a system of connected channels, developed bj^ fusion of originally sejiarate and independent intercellular mesench^Tiial spaces not complicated by any relation whatsoever to the systemic veins, nor charged with the haemophoric function of conveying red blood cells developed in situ into the general haemal circulation.

In the bird the periaortic mesench\Tnal spaces and the resulting channels of the periaortic (thoracic) lymjohatic ducts become in the early development stages charged with the duty of conveying the products of the active periaortic mesenchymal haemopoesis of the bird, as free red blood cells, into the general haemal circulation. Hence, in the bird, we must recognize a distinct haemophoric stage in the ontogen\' of the axial (thoracic duct) lymphatic channel. In the mammal, the products of an early haemopoesis of the periaortic mesenchyme are conveyed directly into the blood vascular sj^stem through the ventro-medial tributaries of the azygos (supra-cardinal) axial veins. These tributaries having performed this function, atrophy and are replaced topographically l)v the anlag(\s of the thoracic ducts, which develop as independent intercellular mesench\Tnal clefts, surrounding the degenerating venous radicles as the "extra intimal" Ijinphatic anlages described in detail by Huntington and McClure. These mammalian " extra-intimal " l>'mphatic anlages finally replace altogether the early haemophoric ventromedial asygos venous plexus, unite with each other to form the channel of the thoracic ducts and make tiieir secondary centripetal connection with the venous system through the link of the jugular lymph sacs. In all three classes of amniote eml)ryos the final result of the genetic processes above outlined is identical, namely, the establishment of a periaortic or paraaortic lymphatic channel, the amniote thoracic duct.

3. Early stages of vasculogenesis in the cat (Felis domestica) with especial

reference to the mesenchymal origin of endothelium . H. von W. Schulte.

From the Anatomical Laboratory of ( 'oluml)ia rniversity.

The variety of the products of endothelium-mesenchyme (v. Szity,

Huntington), connective tissue (Holl, Mall) and blood-cells (Maximow,

Dantschakoff, Weidenreich, MoUier) would seem decisively to invalidate

the floctrine of the specificity of endothelium advanced by Sabin and

PROCEEDINGS / 9

other American investigators, and to establish beyond peradventure the close affinities of endotheUum and mesenchj-me. But if these facts are duly recognized, there is no logical ground for attributing to endothelium a peculiar origin (preferably entodermalj, and mode of increase ^solely by homoplastic proliferation;, or an early and complete independence of the mesoderm, still less of going to the extreme of assigning to endothelium and blood the value of a fourth germ layer, the angioblast of His and Minot.

In the splanchnopleure, in which the early phases of vasculogenesis have been chiefl}' studied, obser\-ation is rendered somewhat difficult on account of the precocity and extent of the vascular anlages and blood islands, which seem to have caused the scant}' but ever present mesenchyme to be overlooked, so that the Gefd^ssfaserblatt has come to be simply the Gefasshlatt of many recent observers.

The somatopleure is a more favorable site for the study of the early phases of va-sculogenesis, because the process is less rapid, the vascular anlages do not preponderate and mask the presence of mesench^-me, and it is further ^\•idely removed from the entoderm, so that the verj' remote possibilit\- of an entodermal origin of endothelium is here completely excluded. It may be noted in passing that all investigators of the incipient stages of vasculogenesis in mammals are in agreement as to the mesodermal origin of blood and endotheUum fKolliker, Heap, Robinson, Janosik, Bonnet, Fleischman, Keibel. Van der Strich, Maximow, Felix).

Prior to the appearance of the somites, the .space between the ectoderm and mesoderm is crossed by fine protoplasmic strands, the fibers of Aurel V. Szity, or interdermal cytodesmata of Studnicka, collectively the mesostroma of the latter author. Along these c^-todesmara cells migrate from the mesoderm and form the inception of the mesenchj-me. An identical migration occurs even earlier in the splanchnopleure, and in both situations long antedates the re.>olution of the sclerotomes into mesenchNTne. In embr>'os of two somites and older the migration continues but is reinforced by a separation of cells in groups from ridges of the mesoderm, a process described and figured in the splanchnopleure by Fleischman, with whose results my own are in close agreement. This process may be termed delamination. It is especially active along the lateral margin of the coelom in the position subsequently occupied b}' the umbilical vein. In some of these masses clefts appear; their enlargement is accompanied by flattening of the enclosing cells; thus separate endothelial vesicles are formed. Similar vesicles are produced, by the same process, above the intermediate cell-masses and have an imperfect segmental arrangement. The intervals between the vesicles are filled with mesenchyme with which their endotheUum is in s>Tic>tial connection. Some of these mesenchyme cells flatten; at first separated by considerable intervals, the flat cells soon coalesce to form strands and plates; in their protoplasm cleft like lumina appear, enlarge and ultimate coalesce with those of the endothelial vesicles, thus gradually establishing continuous vascular charmels. I'p to the stage of fourteen somites

so AMERICAN ASSOCIATION OF ANATOMISTS

tho umltilical vein and the associated jilcxus remain unconnected with the onijjhaloniesenteric vein and the juxta-neiiral anastomosis.

Identical jirocesses give rise to these vessels also the migration of single elements into the mesostroma, delamination, the formation of discrete vesicles and their ultimate coalescence. Mesench\Tne is always present, but scanty in amount.

The first formed vessels of the splanchnopleure are placed in the interval between mesoderm and entoderm. Subsequently they gain more intimate relations with the former layer. From the stage of eight somites they become enclosed l)etween i)rocesses of the visceral mesoderm. At the .stage of twelve somites and later many of these ])roce8ses contain funnel-like diverticula of the coelom, the walls of which are intimately united to the blood vessels; the funnels in many mstances seem to communicate ^^^th the mesenchjTnal spaces. The ])resence of these structures, and the further fact that in early stages, just as the first somites are forming, the lateral part of the \nsceral layer almost wholly resolves itself into mesenchyme, to such a degree that the wall of the coelom becomes incomplete, suggests an intimate morphologic resemblance between the coelom ami the tissue space, the further study of which might be expected to throw some light on the general problem of the relations between the coelom and the vascular apparatus ^s a whole.

4. On the early contractions of the posterior lymph hearts ifi chick embryos — their relation to the body movements. Eleanor Linton Clark and Eliot R. Clark. The Anatomical Department, Johns Hopkins University, lialtimore.

Living chick embryos were observed in a warm chamber, under the binocular microscope. Violent movements, involving the whole musculature of the embryo, were observed at all stages, from four days to the time of hatching. These movements were found to occur periodically: definite periodic spasms of bodily contractions were followed by distinct interv^als of rest.

Definite pulsations of the posterior lymph heart were observed first in chicks of 6| days. The pulsations, at this .stage, were found to be intimately connected wnXh. the periodic movements of the embryo. In subsequent later stages, the IjTnph heart gradually becomes independent in its function.

Chicks were ke))t alive and under continuous oliservation for from 3 to 5 hours and records kept of each lymph heart beat and of all boily movements, in different stages of embrvos.

Stage \. Chicks of 6^ to 7 days (2(3-22 mm. before fixation). Here the l>Tnph heart invariably contracted several times during each period of body movements and never in the period of rest between s])asms. Moreover, a beat of the lymph heart was always accompanied ])v a movement of the tail. When an embryo of this stage was anaesthetized with chloretone. both body movements and lymph heart contractions ceased at the same time. When the effect of the chloretone wore off.

PROCEEDINGS 81

the periodic spasnjs and lymph heart pulsations returned simultaneously and continued as before.

Stage 2. 7 to 7| days (22-24 mm.). The same as stage 1 except that occasional beats of the lymph heart were dissociated from movements of the tail.

Stage 3. 8 days — 24^ mm. The lymph heart contracted several times during each periodic spasm of body movements and occasionally it contracted once, independently, during the period of rest. When the body movements were paralized by chloretone, the lymph heart pulsations continued. They did not occur in periodic groups, however, as before the addition of chloretone, but singly, at irregular intervals, from 4 to 8 times every minute. With the return of the body movements, the lymph heart was again observed to contract several times during each periodic spasm, but it also continued to beat, independently, several times in each period of rest.

Stage 4. 82 to 9 daj^s (27-29 mm.). Fewer beats of the lymph heart occurred during the periodic .spasms, than in earlier stages, and more in the period of rest. When the body movements were eliminated by means of chloretone anaesthesia, the Ijonph heart beat, independently, at irregular intervals, — about 6 to 8 times per minute.

Stage 0. Finally, in a chick of 11 days, the lymph heart pulsations were entirely independent of the periodic bodily movements. Beats were seen to occur during the periodic spasms, but the intervals between such beats were not shorter than between those occurring in the periods of rest, and we observed several spasms during which no hnnph heart pulsations occurred.

AVe have studied, in cross sections, the same embryos observed in the living but we are unable, at present, to offer any conclusive anatomical explanation for the intimate connection between the early pulsations of the IjTnph heart and the periodic movements of the embryo, and for the gradual manner in which the hTuph heart becomes entirely independent.

5. On certain morphological and staining characteristics of the nuclei of lymphatic and blood-vascidar endothe'iuni and of mesenchyme cells, in chick embryos. Eliot R. Clark, The Anatomical Department, Johns Hopkins University, Baltimore.

The nuclei of lymphatic and blood capillaries in chick embr>'os possess morphological and staining characteristics which differentiate them from the nuclei of the surrounding mesenchyme cells. These differences were noted in cross sections of chick embryos in which the blood-vessels were completely injected with india ink, which were fixed in Helly's fluid, carefully dehydrated, imbedded in jiaraffin, sectioned, and stained with Ehrlich's hematoxylin and eosui onmge (^ and aunmtia: Embryo.s of from 4f to 8 days of incubation were .studied.

The nuclei of lymphatic and l)lood-vessel cmlothelium have either a single nucleolus or a i>air of nucleoli which are definite discoid boilies, sharply marked out from the remainder of the nuclear material, with clear-cut, rounded outlines. The single luiclfohis varies much in shape,

THE AJiJATOMlC.M. KKCOHD, Vol . S, NO. 2

89 AMERK'.VN ASSOCL\TION OF ANATOMISTS

Sell extend ou, into prongs and threads and 'tdo^^ ""t^have a char chromatm matenal lymphatic endothelium possesses

r^coi^ertedhlve quite similar eharaeteristics, fum'shes a new proof ttattte lymphatic endothelium is derived from the vems. It also Sstts the study in serial sections of the earliest lymphatics.

6. The development of the azygos ,ei,u a.s shown in i^^^^^^^'^^: Florence R. Sabin, Anatomical Laboratory, Johns Hopkins tni

by some improved "^!^t^«^,.^^'to?al specimens of injected pig embryos

Sir :s- s^3 iS^1^i^ -~. i'-; rri'n axr f.:;' ^ ^^-z:'^z:;.:^t;:jz

veious inieetions. Pure venous '"J<^<^*'™f f"!;,^ (^^'^^^^^^ The >" TT:f"4aaeSr lir "^1™ ^i^c ^rat'fons is' ^^iT So™ from his

Praparaten," pubhshed l)y h Hirzcl, ^3^^^; /;' ,^1^^,,.,,^ instead rtrtfl Xir Tt KS rrr t[;Lth wasHi,.^ are im the Wolffian bodies, the mam vems o the orcein ;^^ ^'^'^^^'T.^ ^^ ^^,^ surface vessels, a dorsal or the posterior cardinal vem, a ventral or

PROCEEDINGS 83

ventro-lateral vein and a mesial or the subcardinal vein of F. T. Lewis. The dorsal vein extends along the dorsal border and receives the segmental spinal veins. The ventral vein extends in the ridge in which lies the Wolffian duct and which marks a general boundary' between a mesial glomerular zone and a lateral tubular zone as seen from the ventral aspect. The vein lies mesial to the duct. The dorsal and ventral veins join at the anterior pole of the Wolffian bodies. The subcardinal vein runs obliquelj' along the mesial surface of the Wolffian bodies. It does not join the posterior cardinal vein at the anterior pole of the organ but rather at a short distance from the anterior pole. It lies ventral to the mesonephritic arteries in the angle between the Wolffian bodies and the root of the mesentery in the position described by Lewis. At the lower pole of the organ it anastomoses with the ventro-lateral vein. Opposite the middle of the organ is the large anastomosis between the subcardinal veins of the two sides making the mesonephritic vein of Minot. The right subcardinal differs from the left, as Lewis discovered in that its anterior end is continued forward into the caval mesentery' to the liver making the vena cava. The subcardinal veins are essentially the mesial veins of the Wolffian bodies, for only on the right side a short trunk of the veins which makes the anastomosis with the liver sinusoids Ues outside of the organ within the caval mesentery-. In embr>'o pigs 7 to 8 mm. long the mesial longitudinal vein is the largest of the three veins.

Besides these three longitudinal veins there is a long series of parallel veins transverse to the longitudinal axis of the organ which run just beneath the capsule and connect the three longitudinal veins. It is these transverse veins which eventually become the main veins of the Wolffian bodies, that is the main roots of the vena cava. As seen from the lateral aspect, the transverse veins connecting the dorsal and ventral veins are small, of about uniform size and ver>' numerous. In injected specimens they give a ladder like effect to the lateral surface. They run parallel to the tubules. On the mesial surface in embryos 7 to 8 mm. long the transverse veins at the anterior pole cephalic to the mesial vein are ver>small. The first large transverse vein is the connection of the mesial vein \Nith the posterior cardinal. From this point caudalward there is a series of very large transverse veins crossing the dorso-mcsial surface of the Wolffian bodies and connecting the subcardinal vein with the posterior cardinal. They pass ventral to the mesonephritic arteries. The largest of them is opposite the middle of the organ where the two subcardinals anastomose, indeed the mesonephritic vein might as well be called an ana.stomosis of the two middle transverse veins. In embryos 7 to 8 mm. long most of Xhv blood from the mesial part of the Wolffian bodies passes l\v the sul)cardinal trmiks through the transverse veins to the posterior cardinal veins and the anastomosis between the right subcardinal and the liver is small. When the eml)ryo is 11 to 12 mm. long the ana.stomosis with the liver is large and the subcardinal veins are the main roots of the vena cava. By the time the pig is 1.') mm. long the vena cava has become very large and the miiUlle transverse veins are its largest roots in the Wolffian bodies, while the posterior cardinal and

84 AMERICAN ASSOCIATION OF ANATOMISTS

ventro-latcral veins have become limited to the anterior pole of the organ. It is at this point that the azygos veins Ijegin.

There have been two theories concerning the origin of the azygos veins, the more accepted one that of Hochstetter that the azygos veins are at least in part transformed posterior cardinal veins: the other advanced by Parker and Tozier from the Harvard laboratory in 1897 and in the same year by Zumstein tiiat the azygos veins are new veins. That this latter view is the correct one I can prove by dissections of injected embryos showing the two veins in the same specimen. In stages below 14 mm. the spinal veins pass directly to the Wolffian bodies in a straight line parallel to the mesial sagittal plane from the spinal ganglia and the tissue dorsal to the aorta around the notochord is non-va.scular. At the stage of 14 mm. there develops from the spinal arteries a capillary plexus, ventral to the vertebrae. These capillaries begin in the cervical region and drain by many branches into the anterior cardinal vein and lower down into the posterior cardinal. In the body region a longitudinal vein develops in this plexus which retains as its permanent connections with the cardinal veins the branches which join the posterior cardinal vein at the point where it curves ventralward to make the duct of Cuvier. This point of connection, as is well known, is at first high up at the root of the neck and gradually shifts caudalward. The only part of the azygos system which is derived from the cardinal system is the ventral curve of the duct of Cuvier. The permanent pattern of the veins in the pig is as follows: on the left side a hemiaz^^gos and an accessor>' hemiazygos enter the heart through a permanent duct of Cuvier, on the right side the azygos vein joins the cardinal at the same level as on the left side but the duct of Cuvier is longer. Corresponding to the accessor>^ hemiazygos there is a larger oblique vein draining more than half of the prevertebral tissue of the first four vertebrae wiiich was de.scribed by Kampmeier as a vein which disappears as the thoracic duct develops. Injections show that it is a developing vein at the time when Kampmeier thought it disappearing. Injections of embryo pigs from 20 to 25 mm. long show the complete posterior cardinal veins together with the azygos and hemiazygos systems. The posterior cardinal vein is always farther ventrtd and farther lateral than tiie azygos. The azygos veins are dorso-lateral to the aorta. Eventually the posterior cardinal veins become tributaries of the azygos system.

7. A comparative diidy of the embryonic blood vefisels and lymphatics in amphibia. Henry McE. Know er. University of Cincinnati In order to understand the development of the lymphatic system, it was necessary first to secure accurate knowledge of the primary arteries and veins and tlieir capillary beds, in relation to regions and organ rudiments, at different stages of the early development of the forms studied. It then became possible to make comparisons withm and outside of the group; and to examine and discuss safely the IjTnphatic system.

Hence this paper is naturally divided, on the one hand, into a section devoted to an outline of the results of a stud>' of the primary vascular

PROCEEDLNGS 85

system of amphibia; with its origin, most important relations, and transformations, as well as a comparative study of these problems and the origin of the blood; while, on the other hand, the second section is concerned with the development of lymphatics in amphibia; the relation of this system to other systems of the body, especially to the tissue spaces and pronephros and mesonephros; the development of lymph hearts; as well as with a comparative discussion of these findings, involving a comprehensive working hypothesis of physiological and experimental nature for the development of the lymphatic system in vertebrates.

The elaboration of proof of so extensive a program ^-dll, of course, demand much more space than is here available.

The method of investigation is predominantly experimental and involves a study of each embryo as a whole. Injections were used not simply to secure a series of morphological forms for comparison, but rather to exhibit and fix for study relations o.' physiological balance between the various vascular beds (dorsal, ventral, lateral, anteroposterior) and the regions of the body, at different critical periods of the embryo's history. It is thus possible to show how, especially in the formative stages, pathways will be opened along lines determined by usual or extraordinary balances in pressure relation; and how in agreement with Mall (on the liver)and Thoma, Evans and Sterzi, and so forth, yet with additions, the main vessels are established in the amphibian embryo as a result of the fixat on of certain physiological streams f^o^v'ing more and more constantly through the capillary anastomoses of different regions.

Young amphibian embryos are especially favorable for such study The simphcity of the entire organism, which can be cleared and viewed in one field; its availability for observation and experiment while alive; -and the important relationships to other forms which permit us to apply our studies to general problems; have, we believe, furnished us a special insight into the problems involved. This carries us some steps further, because it has been possible in the study of the system selected (that is, the lymphatic system) to keep more constantly in touch \\'ith the stages of the other systems of the body, whether arteries, veins, organs or tissues, as parts of one organic mechanism. The interaction of the parts as affecting the problem of development of the vessels and h'mphatics has been tested by experimental injections, and otherwise.

Hoyer for the amphibia, and others for other groups, have made most important contributions l)y studying one system at a time, more or less as an entity, oitlier In' models or injcK'tions. They iiave aimed to arrive at morpiiological comparisons and genetic relations of the system.

It is not to lie denied that many observations of living emlirvos, models, and injections, in our sense, have advimced our knowledge. Evans has brought this together in a most able manner ('13). These methods have not, however, ]iro\ed entirely adequate for reaciiing an appreciation of some very important problems of inter-<iependence of all systems as affecting lymphatics; nor for grasping some essentials in

86 AMERICAN ASSOCIATION OF ANATOMISTS

the (lovolojiniont of blood vessels and l\Tnphatics which might prove common to all methods of approach.

Another great advantage in our studies has been the fact that many of the injections, by our sjiecial method, were of far earlier stages of both Urodeles and Anura than have been secured by others. This has enabled us to clear up some points in the establishment of primary vessels not other^^^se possible.

Our previous work, experimental and other, has been confirmed and extended.

I. Successful injections of young Amblystoma embryos before the postcardinals become defined, furnish a variety of specimens in the same or closely related stages, de])ending upon the jihysiological state of the embryo. It can be shown that the blood from the dorsal aorta leaves this vessel, behind the point where it begins, ventro-laterally all along its course, on either side. We do not find the extremely large sheets nor the same history as von Mollendorf, but can agree with some of his points. Each lateral stream branches into two, a dorsal and a lateroventral. The latter vessels run ventrally over the yolk in a fairly \nde plexus.

In the next stages the blood returning from the bifurcated caudal ends of the aorta, tends to fix a pathway from behind to the pronephric sinus through the vitelline ])lexus, on either side, along and under the edges of the myotomes. This return stream to the j^ronephric sinus will become the postcardinal. It flows through the vitelline anastomosis, and tends to push forward over these outcoming streams, so that when later the vitellme arteries lose connections with the jiostcardinals, they are found beneath (ventral to) these. There is then, for a time, a free coimection from the aorta to the forming postcardinals and outward to the vitelline plexus. The dorsal or neural arteries run up from near the division of the latero-ventrals into their postcardinal (lateral) and vitel- ' line (ventral) branches.

Anteriorly, in the region of the pronephric glomerulus, practically the same condition as behind is found. Several pronephric arteries are found running laterally from the aorta, in intimate association Avith the vitellines of this region related to the vitellines as the lateral vessels to the postcardinals are related to the vitellines in the posterior part of the V)ody. The glomerulus is not a mere saccular enlargement as formerly described, but rather a plexus. It has a venous drainage.

The posterior cardinal is thus a fixation and separation of a venous return from lateral branches of the aorta. These branches are at first also in connection with the neural plexus through the dorsals, along the sides of the aorta. Hence the dorsal, lateral, and ventral aortic branches are to be regarded as primarily derived from one series of latero-ventrals which branch in three directions. Variations as found by Goeppert are numerous in the origin of laterals and ventrals from the aorta.

In frog embryos the postcardinal loses its connection with the sides of the aorta at a very early stage, except in front and behind. Birds also exhibit a secondary condition in this respect, since Evans found no

PROCEEDINGS 87

aortic connections in the mid-body. The anterior and posterior regions remain more primitive. My experimental work of 1907 shows that in frogs the primary connections of aorta and cardinals can be forced to persist.

The umbilical artery of higher forms, as well as the limb-plexus arises from lateral loops of the dorso-lateral aortic branches which are connected, as Hochstetter and Evans claim, from the beginning in the f rimitive maimer just indicated, with the postcardinal and splanchnic vitelline plexus. There is a fundamentally similar condition in amphibia, well shown in young Necturus embryos.

The formation of the definitive arteries and veins of the various divisions of the digestive tract, as esophngus, stomach, liver, intestine, and hind-gut, have been studied. They arise as transformations from plexuses, secondarily, as a result of changes and movements in the tissues and organs of the regions concerned. This is in agreement fundamentally with Mall, Evans, Bremer and in many features ^^^th von MoUendorf, etc., for the estabhshment of the larger trunks in other forms.

These studies go to prove a fundamental similarity between the primary vessels and plexuses of amphibia and those of other vertebrates. We find no ' essential' difference between the vascular .systems of anamniotes on which to base such distinctions as have recently been drawn by Elze. Differences are of degree rather than kind, and we regret that we cannot subscribe to a number of Elze's claims.

Elze's use of our experiments to support his contention is entirely unwarranted; for although these frog embrj'os lived two weeks without a heart, they grew abnormal as they became more and more dependent upon skin breathing alone, in the absence of normal circulation; and, I should now add, in the absence also of a norma exc etory ai)paratus.

There seem to be important bearings of our findings, taken in connection with the results of others and with our own experimental work, on the questions involved in the establishment of the angiol^last and first vessels; the extension of these in the body and over the yolk; and the origin of blood cells.

On the whole, we agree with Bremer ('12) as to the almo.st simultaneous origin of aortae, early gill arches, and t' o vitoliino foundations of the postcardinals. We should modify von Mollendorf's results somewhat for our forms. The angioblast appears to us to consist first of an anastomosing mesh, including heart, early gill loo]is with the anterior part of the aorta and a venous return to the heart througii simple vitelline loops, lying dorso-laterally on the vi Ik. This mesh is fairly continuous. It ])rogresses backward on eitiier side of tlie aorta as the terminal loops of tiie aorta push back. In this way vaso-formative cells and homatopoetic cells are established as claimed i\v many authors, on either side, extending back from the heart, along the line of the aorta, and of the origins of the vitelline arteries to the base of tiie forming tail. As the embryo grows longer, the movement of the vascular rudiment is a general one, in one system of anastomosing looi)s, backward along the

88 AMERICAN ASSOCIATION OF ANATOMISTS

dorso-lat^riil :u>i)oct of the yolk and further out into the tail. It does not seem imjiortant for all parts of the extensive rudiment to exhibit a lumen at once. The loops are inHuenced by tissue activities to grow out, while the non-functional formative tips may not ever\'^vhere l)e clearly marked ofT from surroundinj; tissues in the early rudiments. Later, the vaso-formative activity of the cells of the rudiment lessens; while the endothehal tubes already formed extend by their own gro^vth in wide plexuses, both backward and ventraiward on the yolk and in the body. There is now more difference between the tissue cells and vessel walls.

The wTiter's personal observations on these questions have not been made on the earliest non-injectii)le stages; but nevertheless, as he believes, on stages early enough to indicate the nature of the processes, and to show a definite bearing on his experiments of 1907.

Since the line of extension of the angioblast lies along the roots of the vitelline arteries, that is, also the roots of the mesentery, as far as the base of the tail, it is significant that embryos from which the heart is removed at an early stage ('07) later exhibit collections of blood cells in the mesentery, as well as at the base of the tail.

It must be stated here that a thorough study has also been made of the dorso-lateraf, neural, and other blood vessels in order to value properly the conflicting claims in regard to the lymphatics, especially in the region where these first appear.

II. In turning to the l>nnphatics, we are met by two opposing views: on the one hand, that the lymphatics are outgrowths from the endothelium of the veins; and on the other hand, that they arise b\^ confluence of tissue spaces which run together centripetally to join the veins.

Now, there seems to be no doubt that tissue activities initiate the origin jmd maintain the lymphatics as a system. But why should tissue spaces collect into relatively large vesicles and run together in such definite lines? Is it proven that such actually become a continuation of thelvniphatic .system? Why do we not find enlargements at the end of our vessels, repre.senting vesicles from tissue spaces, on injecting lymph capillaries, instead of invariably finding most delicate tips? Why should the main trunks of this sy.stem, communicating with the veins as they do, arise separately and by an entirely different method than that followed by the venous trunks, which are returns established through a previously functioning generalized plexus?

The technique is evidently very good on both sdes, and in very many points there is possible convergence in interpretation. Both sides proceed on the assumption that nature is constant. Hence, it should not matter whether a stage is studied by models or injections or b}' combined methods; since there is a closer approximation to the truth in each specimen examined. It should be as possible to interpret the facts with the aid of good injections and sections and other sj)ccunens, as by making motiels to express the same facts and interpretations of a constant stage, similar .n many groups. It should be, if anything, easier to determine whether strands of endotlielium at the ends of a definite injectable system invade and tap uninjected spaces of connective tissue, than it is to

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prove that certain indefinite spaces in the connective tissue combine to build up a system running centripetally in definite lines strictly comparable in various groups.

Can we not accept whatever is proved by either side; and even go further, by associating the development of IjTnphatics with other systems of the body, and discover a cause in embrj^os of all vertebrates which will aid us in explaining this system? At least, can we not find a working h\'pothesis?

Turning to the amphibia, we find it possible to make more definite statements about earlier stages, in both frogs and amblystoma, than have been hitherto possible. The first lymph vessels in the frog form a small and superficial dorso-lateral plexus, which drains into the pronephric sinus through a short vein. On this plexus in the frog, the anterior IjTtnph heart soon appears and facilitates the drainage into the venous channels surrounding the pronephric tubules. The Clarks have showTi a similar secondary appearance of the posterior l\Tnph hearts after the plexus is formed in birds ('12). The primary l\Tnphatic endothelial plexus may be thought of as being attracted by some chemotaxis, which arises in the tissue spaces as the mesenchjTiie becomes looser and more vacuolated. This phenomenon of outgrowth is to be observed about the time that the external gills begin to show distinctly, and when the pronephros is organized. The appearance of the first lymphatics at this stage, and in the region of the body where important physiological processes are being inaugurated, suggests strongly that this association is causal. We shall elsewhere give many reasons, and a mass of correlated facts, to justify the view that the early Iv-mphatic plexuses of embr>-os in all vertebrates are endothelial outgrowths, induced to invade vacuolating tissue spaces by changes in the metabolism of this region. The endothelial lymphatic vessels carry off the accumulated products more (lirectly and rapidly from the tissues than would be possible through tissue spaces. It is our view that they can thus be carried more rapidly to the pronephros for elimination. (See Abel, Jour, of Pharm.. 1912). The IjTTiph hearts appear later at the point of entrance of the plexus into the veins, just adjacent to the pronephros and facilitate the emptying of the plexus into the venous channels surrounding its excretorytubules.

As development proceeds, the changes in the tissues l^ringing about vacuolization, spaces, and so forth, progress tailward and take place most actively just under the skin and dorso-laterally.

Coincidentally, the lymphatic plexus travels l)ackward. spreading dorsally and ventrally beneath the skin as it moves. The stages are different in important features from those described !)>• Hoyer. whose older stages did not show the true nature of the plexus, though fundamentally we shall ))e in agreement. In this mamier the dorsal and ventral caudal trunks are laid down as the tissues of the tail favor their invasion. A tlelicate but rather extensively l>nnphatic plexus comes to overlie the veins at the i)ase of the tail l)efore the ap})earance of the ix)st^rior lymph hearts; (we understand Hoyer to be in :igreement with this, though his pupil Fedorowicz seems to disagree).

90 AMERICAN ASSOCIATION OF ANATOMISTS

At first the entire system of lymjihatics drains through the anterior lymph hearts mto the pronepliric sinus. With the inauguration of greater tissue activities in the region of tlie hind-body, with the development of the limbs and of the Wolffian body Anth its special venous channels, bathmg the tubules, a connection is established between the endothelial tubes of the lymphatics and certain branches of the lateral caudal veins. We think PVdoroA\icz's observations are incomplete, or on unfavorable material, and that his cell strands in the tissues near the veins before the posterior lymjih hearts appear will probably prove to be lymph terminals which have been attracted back, as we find, into this region from in front.

Thus the vacuolated, and, as it were, the oedematous tissue spaces of the jiosterior portion of the body are now drained through the posterior lymph hearts into the veins of the mesonephros, where an elimination ma>' take place through the tubules which they surround. (These portions of the tubules, as well as the glomerular sections, are claimed by several authorities to be excretary, while the venous streams are passing through the renal-portal system toward the heart).

This opens up some interesting problems of the functions of the different parts of the pronepheros and mesonephros as compared in embryos of other fonns. The functions of these bodies should also be recompared with those of the kidneys of adult sauropsida and mammals, including man. Since we know of no accurate studies along these lines.

Consistenth' vnih these \'iews, the invasion of the viscera Ijy lymphatics from the roots of the mesenteries should follow the developmental activities of these organs in changing from a simple primary tube as the accompanying active histogenesis gives rise to new chemotaxis favoring this. This is true of the development of the thoracic duct in amphibia and in higher forms.

In Urodeles there is essentially the same history; l)ut here an exceptionally extensive lymphatic plexus overlies the veins very closely, and invades the neighboring comiective tissue; while the numerous lymph hearts appear later connecting the two systems. Hoyer's recent ('12) figure for late salamander larvae, are not quite reconcilable, but can probably be corrected b}^ study of young and late amblystoma, if he has confused veins with overl>nng lymphatic vessels in incomplete injections of the trunk region, as seems possible.

Comparisons of these facts and application of this working hypothesis to the embryos of other forms, including man and mammals, where the nature of the pronepheros appears to produce interesting variations, will be explained fuUj' el.sewhere.

It seems clear that this view of the method aud supposed causes which bring about a 'taping' of the enlarging tissue spaces, permits us to use many of the valuable results, not only of the advocate of the importance of the ti.ssues and tissue spaces in the problem, but also of those who are impressed with the continuity of the endotheUum as it invades the body.

Kxtra-intimal spaces may well prove to be lymphatic capillaries which have travelled along the veins and which undoubtedly exist in my specimens.

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Though I have not seen convincmg cases, demonstrating bej'ond doubt the opening of hinphatic terminals into tissue spaces, this has been claimed by able observers; and though the necessity for this is not yet shown and the proof must be more final, it ^^•ill not be inconsistent \\ith my findings and conclusions, if such opening should be sho^\^^ to be estabUshed. Such a condition might facilitate the passage of substances into the endothelial hmphatic vessels when once this plexus had been induced to invade a region.

At any rate, we must now take into account, in the embrj'os of all vertebrates, the relations of tissue metaboHsm, respiration, the function and character of h-mphatic drainage, with first the pronephros, and later the meso- and meta-nephros. There \vi\\ be found a remarkable time relation, and correlative association, in both normal, and experimented, and pathological embryos where the function of the kidneys, and so forth, are disturbed. This may lead to a dropsy' more or less chronic; which, in certain cases, may even possibly become a habit of a normal stage or species. The jugular sacs of mammals may be somewhat distorted by such influences.

On motion a discussion of the several papers presented at this Session was deferred to the end of the Session and was participated in by George S. Huntington, Henry ^NIcE. Knower, Eliot R. Clark, J. Plaj'fair !McMurrich, C. F. W. IMcClure and Charles R. Stockard.

Monday, December 29, 2.00 p.m. to 5.00 p.m Session for THE reading OF papers, President Ross G. Harrison, presiding.

8. Experiments on the development of blood vessels in the blastoderm of the chick. Adam M. Miller, Anatomical Laboratory, Columbia University, John E. McWhorter, Surgical Laboraton,-, Columbia University.

The object of these experiments on the living blastoderm of the chick has been to derive some evidence bearing on the question of vascularization of the area pcllucida and embryonic body. It was as.->umed that if the entire lateral half of the area opaca was removed from the blastoderm prior to the appearance of vascular anlagen in the area pellucida or embr>'onic bod}' and the blastoderm was then allowed to proceed in develo{> ment, it would be possible to test the validity of the view that blood vessels in the area pellucida and embrj'o proper arise in situ and not i\s ingrowths or sprouts from antecedent vascular anlagen in the area opaca. By examination of living blastoderms and serial transverse sections of blastoderms in successive stages of development, it was found that up to the stage in which the 'head process' (primitive axis) was clearly visible on surface view there were no cells between mesoderm and entoderm in the area pellucida or embryonic body.

92 AMERICAN ASSOCIATION OF ANATOMISTS

We sought, therefore, to remove the entire lateral half of the area opaca and the lateral portion of the area pellucida at a stage not later than the comploto formation of the primitive streak, and thus to prevent, in the further developing blastoderm, possible ingrowth of vascular anlagen from the area opaca of one side. This accomplished, it would follow that any vessels appearing in the remnant of the area pellucida or in the same side of the embryonic body subsequent to operation must have arisen in situ.

Through a 'window' in the egg shell, and with the aid of a binocular microscope, an incision was made in the blastoderm at the proper stage which effectively separated the area opaca and a portion of the area pellucida on one side from the remainder of the blastoderm. The egg was then further incubated under conditions as nearly approximating the normal as possible. More than 50 blastoderms were operated on and allowed to develop subsequently for periods ranging from 20 to 72 hours.

In general, development went on normally (barring slight retardation) on the uninjured side for at least 24 hours. In some cases the anlage of the heart on this side alone developed. This was probably due to the fact that the incision had been so close to the sagittal midplane as to remove the opposite cardiac anlage. Usually after 24 hours the embryo would become abnormal in contour, although the extraembryonic area continued to develop fairly regularly and the heart continued to beat.

On the injured side, between the sagittal mid-plane and the line of incision, practically all the usual structures developed. The cut edges of ectoderm and entoderm healed together, thereby enclosing the mesoderm. The coelom appeared, although irregular in outline. The somites were found in their usual positions.

Active vasculogenesis was foimd to occur not only in the remaining portion of the area pellucida but also in the embryonic body. Numerous blood islands of characteristic appearance, as well as vessels destitute of blood cells, developed in the splanchnic mesoderm. The aorta and the cardinal and umbilical veins ai:)]ieared in proper position. The cells comprising the i)lood islands were differentiated in loco from the mesoderm (mesenchyme), and the vessels appeared for the most part as series of isolated lacunae, in small part as solid cords which subsequently acquired lumina. In the earlier stages neither the blood islands nor the vessels were connected with vascular structures on the uninjured side.

These results show that the removal of tiic entire lateral half of the area opaca at a stage prior to the appearance of vascular anlagen in the area pellucida does not prevent subsequent development of blood cells and vessels in the area pellucida or in the embryonic body on the same side of the sagittal mid-plane. It has been found, on the other hand, that after such an injury vascular structures develop in both localities. The conclusion is justifiable that the blood vessels of the area pellucida and embryo do not grow in from an extrinsic region but arise in situ.

PROCEEDINGS 93

Discussed by Knower and Huntington. In his discussion of this paper Dr. Huntington referred to the fact that Miller and McWhorter's manuscript had been submitted for publication to the Editorial Board of The American Journal of Anatomy and had been returned with what seemed to the authors to be irrelevant suggestions for improvement. The chair ruled these remarks as out of order. The chair was overruled. Huntington, Knower and McMurrich participated in the discussion that ensued.

9. The origin and early development of the posterior lymph heart in the

chick. Randolph West, From the Anatomical Laboratories of

Princeton and Columbia Universities.

Last year at the suggestion of Professor McClure and under his direction, the writer commenced the investigation of the earliest development of the posterior lymph heart in the chick, and the problem has been continued during the present winter under Dr. Huntington at Columbia University.

As only the early development of the posterior lymph heart has been considered, most of the embryos studied have been between 6.5 and 15 mm. in length, although one or two older ones have also been e.xamined. All of the embryos, with one or two exceptions, were injected with india ink through the viteline vessels, the injection being pushed to the point of extravasation for the haemal capillaries. They were then fixed in Zenker's fluid, sectioned, and stained with eosin and methylblue by Mann's method. A few embryos were preserved entire and cleared by Spalteholz's method.

The posterior lymph heart arises, in the chick, in the mesench>Tne lateral to the caudal muscle plate and caudal to the hind limb bud. Before the lymph heart assumes the form of a single sac-like cavity there exists in this same area a plexus of l>Tn]jhatic vessels, whicii later coalesce to form the single cavity of the hnnph heart. Both tiie lymphatic plexus and later the lymph heart are in connection with several of the most anterior coccj^geal veins by means of tlieir lateral branches which pierce the caudal muscle plate, drain the lymphatics and then ])ass outward to drain a haemal ca])illary plexus, which bears a superficial relation to the lymphatic plexus. Concerning the origin and development of this iympatiiic plexus two main points have been observed. First, the lymiihatic plexus arises by the confluence of indejiendentmiinjectible lacunae, bounded at first by uidifferent mesencliyme cells whicli become flattened to form an endothelium. Second, both in the lymi^hatic endothelium and m the surrounding mesenchyme an actiAe haemopoesis is taking j^lace. It is also necessary to consider the growth of the superficial haemal capillary plexus in this neighborhood. This haemal cajiillary plexus extends its borders and becomes richer by the addition of numerous independent blood islands wiiich have been dift'erentiated from the mesenchyme.

94 AMERICAN ASSOCIATION OF ANATOMISTS

It mus: be rcnu'inhored that all of the processes alluded to; the space formation, the haeinojjoesis. the ormation of groups of l)lood cells to enrich the haemal ca])illarv ])lexus, take ]ilace onli/ m the mesench>nne lateral to the caudal muscle plate and caudal to the hind limb bud, and only during the short i)eri()(l of eml)ryonic history jugt prior to and during the formation of the lymjih heart.

First, then let us consider the extension of the haemal capillary plexus. In the 6.5 mm. embryo the mesenchAine lateral to the caudal muscle plate is indififerent. In the 7 mm. embryo the lateral branches of the coccygeal veins have pierced the muscle plate and groups of eosmophile cells have appeared in the mesenchyme. In the 8.5 mm. embryo the capillary plexus, drained bv the lateral branches of the coccygeal veins is present in the form of a few small vessels, and the groups of eosinophile cells are very abmidant. By the time that the embryo has reached the length of 10.5 or 11 mm. the groups of eosinophile cells have practically disappeared and the capillary plexus, now draining the area which they once occupied, has reached a high degree of complexity. So it seems reasonable to conclude that these groups of blood cells have been drained off b}^ the capillary plexus.

The first lymphatic anlagen were observed in the 10.5 mm. embryo. Up to this stage the mesenchyme lateral to the caudal muscle plate has been firm, but now for the fu-st time a distmct loosening of the mesenchjane may be observ^ed near the caudal muscle plate. In the 11 and 12 mm. embrj^o this space formation becomes more and more pronounced, and some of the spaces have acquired a connection \\ith the lateral branches of the coccygeal veins. In the 13, 14, and 15 mm. embryos the spaces have assumed a comparatively large size and many of those spaces .still discomiected with the veins are surrounded b}^ mesenchyme which is ])ecoming flattened to form an endothelium. Of course when these spaces become connected with the veins, the venous blood may back up in them, but this regurgitation of blood from the general circulation is not to be confused with the haemopoesis which is about to be described.

The formation of groups of blood cells which enrich the haemal capillary plexus has l^een noted. In addition many mesench>Tne cells become rounded antl develop into either the white or the red blood cell line as described by Dantschakoff. Many of these blood cells become included in the mesenchymal spaces which form the lymphatic anlagen, antl when these spaces join the developing lym]-)hatic jilexus, the included l)lood cells gain access to the general circulation via the lym])hatic ])lexus and the coccygeal veins. Other of the blood cells having the power of ameboid movement may migrate through the vascular walls, while from the endothel um of the lymphatic plexus a very active haemopoesis is taking place after the embryos have reached the length of 12 mm.

All the evidence found from the study of injected embryos leads to the conclusion that the lymphatic plexus, which later enters into the fonnation of the po.sterior lymijh heart, arises by the confluence of independent mesenchymal spaces which connect secondarily with the

PROCEEDINGS 95

veins, that these spaces are bounded by mesenchyme cells which become flattened to form an endothelium, and that both in the endothehal walls and in the adjacent mesenchyme an active haemopoesis is taking place.

Discussed by Huntington.

10. Experimental mesothelium. William Cogswell Clarke, Department of Surgery, Columbia University.

Following a purely physical injury which destroys the free surface cells of the peritoneum, pleura, or the lining cells of blood vessels, two possibilities exist as to how regeneration of the damaged zone proceeds.

(1) cells grow from the periphery of the given denuded area, taking origin from adjacent, previously existing and intact flat surface cells;

(2) the exposed deep connective tissue cells making up the floor of the injured area as they proliferate, change in form, becoming flattened.

These experiments were undertaken in reference to the latter possibility in the regeneration of surface cells to learn what happens as regards connective tissue cells in contact with a smooth surface, whether solid or fluid; in other words to learn what change in form takes place in the investing connective tissue cells in contact with the surface of a nonirritating foreign body, placed for a time in the subcutaneous tissue of a living animal.

Non-irritating soUd and fluid foreign bodies were used: (1) thin, smooth, chemically clean sterile sheets of celloidin were selected as the best non-irritating foreign body. These foreign bodies were introduced into the Jiving subcutaneous tissue of animals through as small a wound as possible and left for varying periods. Sections were cut both at right angles to and in the plane of the surface cells; (2) paraffin was injected into the cornea, a vessel-free structure, in order to observe later the cells that are found in relation to the surface of the foreign body; (3) those surface cells were also observed which were in relation to stationary collections of fluid exudate in dead spaces or cavities present in the depths of a wound tlirough imperfect coaptation of the walls; (4) finally, in order to introduce the factor of friction as well as of pressure of the given foreign body, a mucous fistula was establisiietl. The duct of a dog's gall blatlder was obliterated by ligature and a rublier tui>e was led through the su])stance of the al)dominal wall from the fundus of the gall bladder through the skin of the left flank. At seven days the rubber tube was pulled out and the mucous secreted by the lining epithelium of the gall l)la(l(l(>r flowed continuously through the fistula. Since no bile entered the bladder, the fistula carried a nearly bland fluid. A section of the fistula was removed for study at the end of twenty-eight days.

Where possil)Ie, sections of all the above specimens were cut in two l)lanes, one at right angles to tlie fining cells in contact with the surfaces of the above foreign bodies, the other tangential to the surface or lining cells. In the case of th(> fining cells in contact with celloidin. a silver salt, protargol. was employed to determine the presence or absence of a mosaic similar to that oi>served in silver iirejiarations of the peritoneal and pleural mesothelium.

96 AMERICAN ASSOCIATION OF ANATOMISTS

The sections showed that the cells in contact with the surface of the foreign bodies were changed in form in all the specimens into large, flat cells placed edge to edge result ng in a definite cellular sheet. The silver salt demonstrated a mosaic of black silvered lines marking the cell outlines of the lining or surface cells. The cells that existed in the mucous fistula were large cells forming at i)oints a continuous lining.

The fact demonstrated in the above experiments that connective tissue cells are changed in form by physical agents into flat, closely disposed cells, the outline of which may be defined by silver salts, makes tenable the conclusion that the exposed connective tissue cells, exposed through sacrifice of surface mesothelial cells of pleura, peritoneum, or pericardium or of the lining endothelial cells of vessels, may become flattened by pressure or friction or both, resulting in regeneration of the surface cells.

Discussed by Huntington, E. R. Clark and Knower.

11. The behavior of elastic tissue in the postfetal occlusion and ultimate

obliteration of certain blood vessels. J. Parsons Schaeffer, From the

Anatom cal Laboratory, Department of Medicine, Yale University.

The preliminary' paper, "The behavior of elastic tissue in'the postfetal

occlus on and obliteration of the ductus arteriosus (BotaUi) in Sus

scrofa," on this work appeared in the February number of the Journal

of Experimental Medicine, vol. 19, 1914, pp. 129-143. Work bearing

further on these problems is now in progress, the results of which will be

published subsequently.

A brief summary of the paper published in the Journal of Experimental Medicine is given here^vith :

1. A study of the histogenesis of elastic tissue in the embryonic ductus arteriosus of Sus scrofa is in accord ^v^th the theory that elastic fibrils are directly differentiated in the outlying i)ortion of the protoplasm of the early connective tissue cell.

2. In the occlusion of the postfetal ductus arteriosus of Sus scrofa there is early a hypertrophy of the internal elastic membrane. Subsequently there takes place a marked delamination of the thickened internal elastic membrane in the production of new and independent elastic fibers and lamellae. The formation of new elastic fibers from jjrefonned elastic tissue is most abundant where the postfetal contraction of the ductus arteriosus is least marked. These new elastic fibers play an important part in the occlusion of the lumen of the postfetal ductus.

3. A.side from the exterLsivo formation of elastic fibers from preformed' elastic tissue, in the occlusion of the postfetal ductus arteriosus of Sus scrofa, there are also some elastic fibrils formed from non-elastic elements, apparently from connective tissue cells.

4.. In some recent preliminary work on ligations of the common carotid artery there was found, after an interval of from eight to twelve days, at some points between the ligatures, a slight but ol)vious cellular thickening of the so-called subendothelial stratum. Some of these cells

PROCEEDINGS 97

ma}' have wandered from the other coats of the vessel, through the inner fenestrated membrane into the subendothelial stratum; others proliferated from cells in loco. Specific stains revealed near the periphery of some of these cells, that is, in the outlying portion of the exoplasm, ver>' dehcate, granular-appearing elastic fibrils, apparently the product of protoplasmic activity.

The reader is referred to the original paper for the details of this work.

Discussed by H. M. Evans.

12. The earliest blood-vessels in man. J. L. Bremer, Department of

Anatomy, Har\'ard ^ledical School.

Heretofore it has been generalh' supposed that in man, as in other vertebrates, the first blood vessels appeared in the yolk-sac, between the entoderm and the mesoderm. The early vascularization of the body-stalk and chorion in man, before the presence of intra-embrj'onic vessels, and before the formation of somites, has been long noted, but usually considered as e\idence of a ver\' rapid gro\\'th from the yolk-sac anlagen. In human embryos ^\-ith the medullary plate of about 1 mm. in length, and with recognizable yolk-sac vessels, several authors have described, in the chorion, chorionic villi, and body-stalk, irregular spaces in the mesoderm, some lined with endothelium, .some without defuiite lining; and recently Grosser and Debeyre have separately mentioned also blood islands in the body-stalk, near the allantois. In still younger embryos, with no vessels or blood islands in the yolk-sac, Jung and later Herzog have called attention to accumulations of cells, occasionally arranged around a lumen, seen here and there at the periphery of the mesoderm of the body-stalk, which Herzog regarded as the earhest anlagen of the yolk-sac blood vessels.

By the recognition of the fact that apparently isolatetl endothelial spaces, or angiocysts, may be comiected by solid cords of endothelium, as demonstrated in a former paper on the origin of the aorta. I was able to reconstruct, in a 1 mm. human embryo in the Harvard Embr^'ological Collection, and in the 1 mm. embryo described in 1913 by Grosser (who most kindly allowed me to study carefully this excellently preser\'ed specimen) continuous nets, composed of angiocysts and solid cords, extending in each embryo throughout the chorion, chorionic villi, and body-stalk. In Grosser's emi)ryo this net anastomoses at one point with the similar net in the yolk-sac; in the other embryo such anastomosis was not fomid. The 'irregular spaces' thus form part of a vascular system. Young blood corjiuscles can occasionally l)c seen within the angiocysts, and the blood island of Grosser is connectetl with the net.

Grosser first called special attention to the epithelial layer of mesodermal cells, the mesothelium. which forms the coelomic surface of the yolk-sac and of the body-stalk in his 1 mm. embryo, eniiing abruptly at the junction of body-stalk and chorion. Moreover he pointeil out that this mesothelium. mstead of forming a .•^mootii surface. dipjxHl in irregularly, giving in sections the appearance of festoons. I found, in

THK WATOMICAL RECORD, VOL. 8, .VO. 2

98 AMERICAN ASSOCIATION OF ANATOMISTS

both embryos, that the i)rolongations inward, toward the center of the body-stalk, often joined the angiocysts or the cords of the vascular net, and that cells resemblinp; young l)lood corpuscles occasionallj^ were included in these mesothelial strands. Some of the angiocysts not connected with the general net were seen to be inde])end('ntly connected by such strands witii the mesotliolium.

In the Herzog embryo, in which there are no blood islands or vessels in the yolk-sac, the mesothelium of the body-stalk is not a complete layer, much of the surface at tiie edge of the coelom being represented by mesenchymal processes or fibers. "Where present, liowever, the mesothelium occasionally dips inward, thus lining a funnel-shaped extension of the coelom, and in one case at least the end of this funnel can be traced to a solid cord of cells which runs out into the chorion. Other such cords in the chorion can be traced from the body-stalk for some distance, and can be seen to anastomose, forming a net. Herzog's ' blood vessels,' rings of cells on the outer border of the body-stalk, are found to be tangential sections of the festoons between funnels.

If we recognize this net of angiocysts and solid cords as vascular anlagen, then the presence of such a net in the chorion and body-stalk, unconnected probably' in one 1 mm. embryo with the vessels of the yolk-sac, and the presence of a similar though much less extensive net in a younger embryo, where yolk-sac vessels do not exist, shows that blood-vessels arise, which are not only independent of those on the yolk-sac, but even antedate the latter. My observations suggest that they originate from ingrowths of the mesothelium as a number of separated cords, angiocysts, or blood islands, which are soon connected by sprouts of endothelium; that these sprouts may extend along the chorion, as a net, enlarging here and there into angiocysts, and later connecting with the yolk-sac vessels.

Discussed by Schulte.

ISa. The relation between chemical constitution, physical properties, and

ability of the benzidine dyes to behave as vital stains. Herbert M.

Evans, Johns Hopkins University, Research Associate, Carnegie

Institute of Washington.

These experiments which will be published in extenso with W. Schulemann have shown in brief that the chemical constitution is of no direct influence on the capacity of the dyes to act as vital stains, but is of indirect importance inasmuch as it affects the phj'sical state of the solution of the dye in water. The entire series of dj'es of this class, that is. those made by combining two molecules of an amino-naphtol, naphtol or naphthylamine sulfonic acid with one molecule of a para-diamine base (benzidine, tolodine, dianisidine). act as vital stains in the sense here emi)loyed. for they are taken up and stored in the cytoplasm of those cells which react to trypanblue, Many of these dyes, however, do not diffuse sufiicientl}^ to give a general vital stain of the cells concerned in the whole body. These more 'negative' dyes are very sensitive to

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99

electrolytes which precipitate aggregated dye particles from them. The ultramicroscopic picture of such negative dyes in contrast to that of trypanVjlue reveals their greater richness in molecular aggregates and coarser suspended particles incapable of diffusion. The study has revealed the possibility of higher sulfonated combinations with diffusion rates exceeding that of trypanblue. Such dyes, however, are taken into the cell by virtue of the same forces concerned in the reception of the large particles of negative dyes on the part of cells contiguous to them. This is in turn identical with the forces concerned in the reception of larger particles (bacteria, carbon, and so forth) into the cell, an act long known as phagocytosis and having as its basis from the studies of Hamburger and others surface tension alterations. The research consequently extends downwards very appreciably the size of particles which are known to affect the cell and be received into it by virtue of surface or ' adhesive phenomena.' The cells whose protoplasm is especially sensitive in this way form a sharply defined group by themselves and deserve to be classed together with regard to this common peculiarity, that is, that of reacting to particulate matter. The experimental analysis of cells on the basis of their behavior towards various agents is certainly of the greatest worth in tracing the genetic relations and degree of specificity of cell types.

13b. The physiology of endotheliuyn} Herbert M. Ev.vns, Johns Hopkins University, Research Associate, Carnegie Institution of Washington.

These studies had for their original aim, an analysis of the vital stain obtained by an injection of various benzidine dyes into the blood stream of living animals. The dyes were first used in this connection l)y Ehrlich and Shiga ('05) and by Nicolle and Mesnil ('06). Trypanblue may be taken as a type of the series. It is formed by the combination of two molecules of 1.8 amidonaphtol 3.6 disulphonic acid with one molecule of ortho-tolodine in alkaline solution, and hence may be represented by the formula :

NH? OH

OH NH2

NaOaS

NS=NJ

CH3

\n=n/\A

CHj

SOaNa

NaOaS

■SOaNa

' The work reportrd is based (»n more extensive publieations i,part of which have as yet not appearcil) written by the author in collaboration with: (1) Werner Schuleinann and Felix Wilborn, "Die vitale Farbunp mit sauren FarbstofFcn." Jahresbcricht D. Schlesischen Gesellschaft fiir vaterlandische Cultur. Xaturwissensch. Scktion, Sitzunp voni '^^ Jan.. I'.M.'i Hreslau, 1013. ^2) Werner Schulcmann, "The action of vital stains belonging to the benzidine group," Science, 1014. (3) Ibid "The action of acid a«o dyes and related bodies."

100 .■VMERIC.^N ASSOCIATION OF ANATOMISTS

Wlicn 1 per cent aqueous solutions of some of these dyes are injected into the hving animals (by the intravenous, intraperitoneal, or subcutaneous route) there results a profuse coloration of the skin, raucous membranes, sclerae, etc., which is not inimical to health and persists for many days. The color imparted soon after injection is due merely to the free diffusion of the dye into the chief body fluids and tissue juices; but after a short time, the dye is taken up by certain cells in sufficient quantity to be seen as distinct 'dye granules' in the cytoplasm. The concentration of the dye in this manner is jjrobably a storage of the dye particles in intracellular localities or depots where it is relatively separate from the living protoplasm and the phenomenon is only shown by living cells, dead cells staining profusely and uniformly. These reasons justify the term 'vital stain.' All of the cells of the body do not behave in this way. In organs, which are mainly epithelial, the vital benzidine dye may be seen only in cells of the connective tissue framework. In common with most epithelia and with the central nervous system, the blood cells remahi free from any trace of the stain. On the other hantl certain cells react intensively to the dye and become filled with large ])rilliant granules and vacuoles which mark them out in sharp contrast to their mistained neighbors which have had equal access to the dye. Among these ' vitally stained' cells two tj'pes are predominate: (1) The clasmatocytes (resting wandering cells) of the comiective tissues and makrophages of the great serous cavities. (2) The endothelium in certain special localities (liver, IjTnph glands, bone marrow, spleen).

In atklition to the intense reaction of these cells, certain other cells react less intensively to the stain and are normally foimd with much smaller, often very minute 'granules' of the stain. To such cells belong (1) The fixed connective tissue cells. ('2) The mesothelium, for example, lining the peritoneum and covering its organs. (The kichiey constitutes an exception to the usual negative behavior of epithelium towards the stain for it shows intense dye granules in the e])itlielium of its convoluted tubules, es]iecially those of the first order, and in addition free dye in the loops and in various ])ortions of the collecting system so that the stain intensifies the lines of Peter in its gross morphology; the liver cells also acce))t and store the dye).

The positive behavior of the endothelium in various localities towards the stains, and the negative reaction of the ijlood cells, offers an unusual opjiortunity to distinguish these two cells types in various proliferations due to infection, wound-healing, etc. Many experiments of this sort

A monograph. (4) S. J. Crowe, "Studies on the behavior of endothelium." (5) M. C. Winternitz, and F. B. Bowman, "Ueber die vitalc Fiirbung des Tuberkels," Ccntralbl. f. Bakteriologie, I Abt. G.5 Bd. 1912, Ilcft 4, 5. (6) Ibid "An experimental study of the histoRcncsis of the miliary tuberc-le in vitally stained rabbits," Journal of Experimental Medicine, 1914. (7) J. T. MacCurdy, "Experimentelle iJisioncn des Centralnervcnsystems, untersucht mit Hilfe der vitalen Fiirbung," Bcr. Klin. Woch. 1912, Nr. 36.

PROCEEDEXGS 101

have been made and the great proliferative capacity of the endothelium proven. It has been possible to establish beyond a doubt the endothelial nature of the giant cells and epitheUoid cells in miliary tubercles. (Evans, Bo\\'man, Wintemitz, Journal of Experimental Medicine, 1914), Similar clarity has been secured on the active rule of endothelium in experimental thrombosis and emboUsm.

Much interest attaches to the hght these studies throw on the normal activities of endothelium. The v-ital stain shows that the great mononuclear cells which are set free in the h-mphatic sinuses of h-mph glands, especially in the medullary sinuses, behave identically %\ith the endothelium of these .sinuses and in contrast to the behavior of the mononuclear blood cells. The}' are stained deeplj- \'itally and hence in this respect related to the endothehum. Their actual origin from the endothelium may be seen in all cases where their active formation is called forth. The.se cells have long been known to pathologists and their endothelial nature championed by various observers, above all by F. B Mallorj-. The \-ital .stain establishes this view. These cells are in great abundance in the h-mph glands in cases of t^-phoid fever, anterior pohomyehtis, and a great variety of infections. Their importance in the defense of the body can hardh' be exaggerated. It is of interest that, whereas, singularly few of these cells exist in the general circulation, they may under the influence of disease or any excitant to their formation, appear in the general blood stream. They have in fact been seen in the peripheral blood (ear) by various clinical observers A\'ithout a correct interpretation of their nature being at that time possible (see for example, F. \'an Xiivs, "An extraordinarv blood," Boston Medical and Surgical Journal, CLVI, p. 390, 1907: W B. Bartlett, Pub. Mass Gen Hosp., Vol. 2, p. 390, 1908).

The experimental production of such a comhtion (where the.se cells, endothel ocytes, exist in the general circulation) can be secured by a long continued injection of the benzidine dyes themselves and in these cases the cells in question are in brilliant contra.st to the mononuclear hematogenous elements by \'irtue of their dye content.

It is highly probable that the endothehal cells of the organs in question, namely, l^Tuph glands, bone-marrow, liver and spleeh, are of the greatest importance in the defense against bacterial disease and that they form and set free the so-called anti-))odies in immunity.

Discus.sed by Bremer and Evans.

14- Concerning certain cytological characteristia^ of the erythroblasts in

the pig embryo, and the origin of non-nucleated erythrocytes by a process

of cytoplasmic constriction. V. E. E.\rMEL, Department of .\natomy,

Washington University Med cal School, St. Louis.

Tiic various views which have arisen in the history of the problem of

the origin of the non-nucloated erythrocyte may he briefly i^tatod as m duding that of intra-cellular nuclear disintegration, nuclear persistence,

the hematoblast theory, intra-cellular formation, and the nuclear ex

102 -VMERIC.\N ASSOCLA.TION OF ANATOMISTS

trusion theory. With the exception of the hematobiast theory, all of these views are still being more or less seriously discussed, although at tlie present time that of nuclear extrusion appears to have the greater number of adherents In contrast to these theories the following results of a study of fresh and fixed blood and blood cultures are apparently indicative of another possible mode of origin for non-nucleated red blood corpuscles.

It was found that the erj^throblast of 1 he pig embryo in place of being spherical, as generally described, may in the later stages of cytomorphosis assume a biconcave or cup shape; its nucleus becomes smaller, more compact, eccentric in position, and not infrequently flattened in form; mechanically rotated, the erythroblasts tend to orient themselves with the nuclear region remaining on the under side, as if loaded ; and that their reaction to changes in osmotic conditions indicates a structural difference between the nuclear and cytoplasmic poles. These observations were discussed with reference to the question of the correlation of the form of the definitive plastid ^vith the enucleation of the erythroblast, the formation of a lecithin containing membrane, hemoglobin differentiation, and the factors involved in determining the eccentric position of the nucleus.

In some eighty culture experiments non-nucleated erythrocytes or plastids were observed to arise from the parent erythroblast bj^ a process of cytoplasmic constriction. In size, form, hemoglobin content and stain these culture plastids are comparable to the normal circulatory plastids. Observations on living and fixed material indicate the occurrence of a similar process within the embryo. These results accordingly raise the question whether the origin of non-nucleated red blood corpuscles by a process of cytoplasmic constriction rather than by nuclear extrusion or intra-cellular nuclear disintegration does not merit more serious consideration.

A more detailed description and discussion of the data is in press for publication in The American Journal of Anatomy.

15. The formation of red blood cells in the developing thymus of the pig. J. A. BadertscheTR, Cornell University.

16. The relations of mitochondria in cells multiplying by mitotic and amitotic division. E. V. Cowdry, Johns Hopkins Medical School. The object was to determine w^hether there are any changes in the

number, shape or cytoplasmic arrangement of mitochondria during cell division.

Material: chick embryos, primitive streak stages to 31 somites. Technique: (1) Meves' iron hematoxylin method; (2) same, \vith counterstain of erythrosin; (3) Benda's method; (4) Bensley's anilin fuchsin methyl green method; (5) Bensley's anilin fuchsin toluidin blue method; (0) Bensley's anilin fuchsin methylene blue erythrosinate method and (7) janus green intravitam.

Results: 1,000 cells were studied by the first method in process of

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division; 907 were in mitosis and 93 in apparent amitosis. With regard to mitochondria in mitosis: Out of the 907, 73 showed a relative increase in number, 74 a decrease; of the same cells 4 showed larger mitochondria and 259 more granular ones; 361 out of the 907 cells were in the metaphase ; none of them showed mitochondria in the spindle. The observations on amitosis are incomplete.

The general conclusion is that in the material studied, the number, shape and arrangement of mitochondria during mitotic div.sion is essentially the same as in non-dividing cells.

17a. Ameboid movement in the corial melanophores of frogs. Davenport Hooker, Anatomical Laboratory, Medical Department of Yale University'.

1. The pigment granules contained wdthin the melanophores of larv'al and adult frogs are carried in the cell cytoplasm and not in intracellular canals, a'ong rod-like structures nor in a speciahzed type of protoplasm. They show further, no definite relation or arrangement to one another nor to the nucleus.

2. The melanophores of both larval and adult frogs lie in preformed spaces in the connective tissue and corium, respectivel}'. The melanophores of adult frogs fill the branches of their preformed spaces in the fully expanded phase, those of tadpoles do not

3. The melanophores of adult frogs have expansion-phase patterns which are constant for each cell and which are forced upon the cells by their preformed spaces.

4. The melanophores of both larval and adult frogs expand and contract ■within the spaces which enclose them. As the processes of expansion and contraction are performed by means of pseudopodia, these cells are ameboid.

17b. The developynent of stellate pigment cells in plastyia cultures of frog

epidermis. Davenport Hooker, From the Anatomical Laboratory,

Medical department of Yale University

The prevailing theory iii regard to the presence of pigment in the epidermis is that the cells containing it have wandered in from the underlying connective tissue and that the epidermis j^er se may not elaborate melanine. In this connection the following ol)servations may be of interest.

In Harrison plasma cu'tures of the e])idermis of 3 to 4 mm. embryos of Kana pipiens, the elaboration of pigment was observed in some of the epidermal cells. At first appearing as a mass of b^o^^•n granules in the immediate vicinity of the nucleus, the pigment gradually spread throughout the entire cell. The ratio of i)ignient -forming cells to those which formed none was about 3 to 1. After the ehiboration of a considerable amount of pigment, these cells, either actively or passively migrated to a position below the non pigment-bearing cells. In this position, several assumed a stellate form by sending out pseudopodia. The cultures were at this time four montiis old. tiio plasma having been fre

104 AMERICAN ASSOCL\TION OF ANATOMISTS

qucntly renewed. The cells remained in this condition until the accidental destruction of the i)repara1ions, four and a half months from their hep^innins Whether these cells remain as the permanent pigment cells of the adult frop; epidermis is uncertain and even (juestionahle, hut the observations <lemonstrate that certain ei)idermal cells may elaborate pigment within themselves. Harrison ob.served the formation of pigment in cells of the medullary tube in lymph cultures. Study of tissues, especially in vitro, demon.strates that the ability to form pigment is normally very widespread throughout embryonic development.

18. Vital staining of the interstitial cells of the testis. R. H. Whitehead,

Anatomical Laboratory of the University of Virginia.

The theory advanced thirty years ago by v. Bardeleben that the interstitial cells of the testis are capable of passing through the walls of the seminiferous tubules and there f miction as Sertoli cells received no support from subsequent students of the subject until quite recently. The late E. Goldmann (Die aeussere u. innere Sekretion in Lichte der ' vitalen Faerbung,' Tuebingen, '09) in the course of an extensive study of various tissues and organs by \ital staining, especially w'ith pyrrholblau, investigated the interstitial cells of the testis. He injected subcutaneously into white mice 10 cc. of a 1 per cent watery solution of this dj^e everj' two or three days for ten days, and after killing the animals examined the tissues for the most part in frozen sections. The interstitial cells take the dye and so are readily recognized; the epithelium of the tubules is quite free from it. He states that the interstitial cells can be observed in all stages of migration up to complete entrance ^vithin the tubules. His observations were subsequently confirmed by J. Kyrle (Ueber die Regenerationsvorgaenge in tierischcn u. menschlichen Hoden, Wien, '11).

It is difficult to see how, if the observations of these investigators are correct, this i)ehavior of the interstitial cells could have escaped the many who have studied them in innumerable sections; and it seemed worth while to repeat the experiments, relying, how'ever, upon thin sections of imbedded material rather than u])on frozen sections. The organs were fixed in 10 per cent formalin, dehydrated in acetone (the dye is (juite soluble m alcohol and in water), cleared in xylol, imbedded in paraffin, and sectioned at 7 micra. Congo red was used as a counter stain; it stains quickly and brings out the walls of the tubules quite distinctly.

In such sections the interstitial cells are not all stained \\ath the pyrrholblau, l)ut cells containing the blue grahis are sufficiently numerous U) allow conclusions. In none of the sections have 1 been al)le to see any evidence of the migration of interstitial cells into the tubules. Accordingly I conclude that the observations of Goldmami need further confinnation before they can be accepted.

PROCEEDINGS 105

Tuesday, December 30th, 9.30 a. m. to 12.00 m. Session for

THE READING OF PAPERS, PRESIDENT RoSS G. HaRRISON AND ViCE

President Thomas G. Lee, presiding.

19. The development and growth of the incisor teeth of the albino rat. William H. F. Addison and J. L. Appleton, University of Pennsylvania, Philadelphia, Pa.

30. Development of the pancreatic duct-system in the pig. George W,

Corner, Johns Hopkins University.

The author ha.s injected the pancreatic ducts of pig embrj'os, and reports the following observations: The youngest stage at which the injection of the ducts is possible is at 30 mm. total length. At this time the ducts form a capillar}- plexus with frequent anastomoses. At 40 mm. certain strands of the plexus begin to dilate, and at 50 mm. they have formed a well-marked main-duct. The picture so closely resembles the formation of blood-vessels from plexuses that it is suggested that there may be a flow through the pancreas at an early stage, thus bringing about the formation of the main duct-channel (In discus.sing the paper, Professor Bensley confirmed the .statement that the pancreas secret-es at a very early period). At 60 mm. there begin to grow out from the anastomosing capillaries little branching, non-astomosing t^\-igs, similar to those found by Laguesse in the sheep (by recoiLstruction from sections) and called by him primitive vesicles. These t\\igs replace the plexus, and grow into the great duct-tree of the adult. Above 110 mm. no anastomoses between ducts may be found by the injection method. This work will be pubhshed in full as part of a paper on "The structural unit and growi;h of the pig's pancreas."

Discussed by Bensley, Scammon and Corner.

21. On the pelvis of the human embryo. John Warren.

Two features of the development of the human pelvis were present^ at the meeting of Anatomists in December — one, the early development of the inguinal region and the formation of the gubemaculum testis, and secondly, the early development of the muscles of the jierineum and pelvic floor. Observations were made on human embryos of IS mm., 10.3 mm., 22.8 mm., 29 mm., 37 mm., and 42 mm. head-rump length, all taken from the Harvard ICmbryological Collection. The first apl^earance of the gubemaculum testis was obser^-ed in an embr>'o of 18 mm. It appears at first as a slight thickening in the lateral wall of the abdomen ijefore there is any trace of the abdominal musculature. This thickening forms a crest in the ventro-lateral wall of the al)domen. the inguinal crest, which becomes attached to the lateral portion of the urogenital fold, and in this way a .'^mall recess in the coeloni is cut off behind the inguinal (T(\«<t. In an emliryo of 1«) mm. the mass of connective tissue which represents the gubemaculum is more clearly diflferentiated.

lOG AMERICAN ASSOCIATION OF ANATOMISTS

and it streams out into the connective tissue of the abdominal wall ^\^thout any very distinct pcrijiheral limits. In an embryo of 22.8 mm. the three layers of the abdominal musculature are now distinct. The ^;ubemaculum can be clearly differentiated from them and its peripheral (nid is already presenting at the luture external abdominal ring. The ridge formed by the gubemaculum on the ventro-lateral side of the abdominal wall is very marked and in frontal section the gubemaculum appears as a roundish mass of mesenchyme with fairly distinct outlines. In an embrj'o of 29 mm. essentially the same conditions are found, but we have here the first traces of a processus vaginalis, which extends through two or three sections on the mesial aspect of the gubemaculum, forming a tiny pouch penetrating the substance of the abdominal wall. The elevation formecl by the gubemaculum over the ventral-lateral aspect of the abdominal wall is very striking. In an embryo of 42 mm. the gubemaculum appears as a large oval mass of tissue entering the al)dominal wall at the internal abdominal ring, which is clearly differentiated. The processus vaginalis extends through a dozen or fifteeen sections, being found principally on the mesial aspect of the gubemaculum, and also for a limited extent on its lateral aspect. At the external abdominal ring the gubemaculum becomes directly continuous with a fan-shaped mass of mesenchyme which spreads up and down in the subcutaneous tissue of the lower part of the abdominal wall. This represents the ligamentum scroti, and extends do\\Ti to the base of the future scrotal folds. As regards the development of the muscles of the perineum and of the pelvic floor, the first distinct tra- e§ of the levator ani muscle and of the external sphincter muscle of the rectum could be clearly observed in the 18. mm. embryo. They appeared as thickenings in the mesenchyme and were only fairly well differentiated from the surrounding tissue. In the 22.8 mm. enil)ryo the two muscles were very well marked. The levator ani muscle especially shows at this stage almost its exact adult relations to the rectum and to the genitalia. The topographical position of the future ischio-rectal fossa was very clearly defined. No trace could be observed at this stage of the muscles of the perineum, though the perineal nerves and vesse's were very distinct. In the 29. mm. embryo the levator ani and the external sph ncter were essentially the same as in the pre\^ous stage. The first trace of the ischiocavemosus muscle and of the bulijocavernosus muscle appeared as a thin superficial layer of fil)ers, lying in the first instance on the mesial aspect of the primitive crus penis, and on the lateral aspect of the future spongy portion of the penis. In the 37. mm; embryo all these muscles were very sharply defined. The external s]ihincter of the rectum formed a suprisingly thick ring-like mass of muscle, surrounding the lower end of the rectum. The levator ani was distinctly divided into two parts, — an anterior part, fairly thin which covered over the lateral wall of the rectum, and a thicker, rounded, posterior portion, which had no direct relation to the rectum. The bulbocavemosus and ischiocavemosus muscles were very clearly outlined and the perineal nerves could be traced directlj' mto them. Only a very ill-defined con

PROCEEDINGS 107

densation of mesenchyme gave a slight hint of the triangular ligament and of the transversus perinei muscle, these layers being apparently developed later than this stage.

22. A case of hemicerebellar atrophy in a chiUl. Oliver S. Strong,

Anatomical Laboratory, Columbia University.

The clinical symptoms were not carefully studied but the following were communicated, from memory, by the physician in charge.

The child was three years and four months old. It was small, its head was small and all its movements weak and unsteady. It sat up all day in a high-backed chair. It could walk, but with a very uncertain gait, staggering, and with a tendency to hold fast to chairs. It was unstead}' in grasping a proffered object. It could move its head slowly, and continuously moved it from side to side, usually humming a tune (without words). It had a marked bilateral nystagmus, exact type not noted. It was mentally very weak, appeared very dull, took little interest in toys, and so forth. It talked poorly and indistinctly, with scarcely any formed sentences. Death was due to measles and broncho-pneumonia.

Inspection of the external surface of the brain showed the follo'^ing: The left hemisphere of the cerebellum was entirely absent except a small lobe apparently representing the flocculus. The median lobe was present, though in a defect of this kind, obviously congenital, an exact identification of parts is difficult. The right ohve was apparently entirely absent, the left olive normal. The cranial nerves were apparently normal. T! e pons was very asymmetrical, the transverse fibers and middle peduncle were normal on the right side but enormously reduced on the left side, so much reduced that the VII and V nerves issued in immediate contiguity with each other. The pons protruded much more on the left side. The left pes was wider than the right.

A dorsal view of the brain stem, with the cerebellum removed, showed a curv^ature of the median line with the convexity toward the left. The left clava and cuneus were longer than the right, extending further cephalad. The two trigona hypoglossi were nearly sjTnmetrical, the left ala cinerea, the left eminentia abducentis and the left trigonum acustici also extended further cephalad than tht right. This as^Miimetri' of clavae, cunei, alae cinereae and trigona acustici would apparently be due to the unec|ual pressure upon the medulla of the asNTiimetrical cerebeLum. The left corpus restiforme was much small than the right.

The right superior peduncle was much larger than the left. Some transverse cuts made through the cerebellum did not reveal any left nucleus dentatus. The inferior coUiculi were asymmetrical, the left being narrower, more prominent and protruding farther caudad and its brachium appearing less prominent than that of the right. The left superior coUiculus appeared to be largely lacking. There appeared to be some atrojihy in the jiostcrior frontal, central and possibly part of the parietal l()l)es of the right cerebral hemisphere.

Sections wore made and stained i)y the Weigert-Pal method, somewhat modified. They showed the following:

108 AMERICAN ASSOCIATION OF ANATOMISTS

In the cervical cord no asymmetry was noted. The spinocerebellar tracts are present on l>oth sides ami the lighter areas, usually taken as marking the location of Hehvig's tracts, are present on both sides. There is no evidence of an absence of a rubro-s])inal tract on one side but this as\inmetrv ])robal)ly would no ' e discernible if present.

In the medulla, whether there is an asymmetry of the arcuate nuclei is somewhat doubtful. No asymmetry was observed in the external nuclei of the columns of Burdach nor was there any noticeable as\'mmetry in the lateral nuclei. All of these three structures then, as far as they are connected with the cerebellum, would either be connected equally with each half or only with the median lobe and flocculus.

The left olive is perhaps somewhat hypertrophied. The right olive is represented by a smal U-shaped mass of gray \\'ithout minor folds which extends from about the same level caudally to nearly the same level cephalad as the left olive. The caudal part of this atrophic right olive is the larger and there can also be made out vestiges of a median and dorsal accessory olive. The olivo-cerebellar fibers from left olive to right cerebellum are conspicuous, those from right ohve to left cerebellum nearly a))sent. It is obvious that the olive is almost entirely or, not improbably, entirely connected with the opposite half of the cerebellum, for the left fiocculus-like lobe and left half of the median lobe would l)e sufficient to account for the presence of the small right olive. The left central tegmental tract is much more conspicuous than the right. The right medial lemniscus is larger than the left. The reason for this is not entireh^ apparent. The right nuclei pontis are largely but not entirely absent. There is a small, atrophic left middle cerebellar peduncle. On the other hand the left nuclei pontis appear to be, perhaps, somewhat hypertrophied. The vicinity of the medial lemniscus is invaded by masses of gray apparently connected \\ith pontile fibers and representing aberrant pontile nuclei. Either from these nuclei or from the left pons, bundles of fibers resembling transverse pontile fibers cross the median line in company with the trapesius fibers and appear to join the opposite middle cerebellar peduncle. These fibers would appear to be aberrant t];;^nsverse pontile fibers. There could not be detected any marked a.symmetry of the perpendicular pontile fibers. The left crusta is about three times as wide as the right, mdicating the absence of the pallio-pontile fibers in the latter. The substantia nigra is correspondingly unequal. The central gray of the right locus coeruleus is thicker than the left and contains a number of bundles of aberrant fibers. These fibers apjjear to pass caudad to a region where it would seem they must be connectetl \Wth the juxta-restiform Ijody but this could not be determined with certainty OAving to defects in the series. These fibers also pass into the reticular formation accompanying or connected with peculiar .streaks of gray passing through the reticular formation ventro-latcrally. Some of these fibers ])os.sil)ly join the pons. Further cephalad, in the isthmus, a conspicuous bundle emerges from the central gray of the riglit floor of the ventricle and pa.s.ses ventrally in the raph^, possibly entering the pons.

PROCEEDINGS 109

There is a minute left nucleus dentatus and a very small left superior peduncle. The practical absence of this peduncle causes a marked asymmetry in the arrangement of the lemnisci of the two sides. The right nucleus ruber is largely absent, whether completely absent could not be established owing to a defect in the series.

From the above it is evident that the afferent pallioponto-cerebellar path to the left cerebellar hemisphere and the efferent dentato-rubral path from the left cerebellar hemisphere are nearly entirely absent. Of the inferior peduncle, those spino-cerebellar connections, whether interrupted in cord or bulb, which are supposed to be afferent to the median lobe appear to be practically intact; the olivo-cerebellar part of the inferior peduncle however, is nearly absent and must be regarded as passing principally or entirely to the hemisphere, in accordance with the work of other recent investigators

Discussed by B. D. Myers and Harrison.

23. The morphology and development of the floor of the interhrain in

mammals. Frederick Tilney, From the Department of Anatomy,

Columbia University'.

The object of this paper is to present a study of the floor of the interbrain in mamals by means of the reconstruction method. This method was applied to several forms, among which were the adult cat, dog, rat, and rabbit. Observations were also made upon serial sections obtained from a number of other mammals including marsupials, rodents, ungulates, carnivores, primates and man. In the light of this study the third ventricle reveals itself as a more complex chamber of the brain than would appear from the usual description of it. Its complexity is due to the presence of several accessory recesses, each of which is indicated upon the surface by an eminence or protuberance. Some of these structures have previously been recognized but their phylogenetic significance has not been altogether clear. By reconstructions demonstrating the development of the diencephalon in the cat, it was possii)le to trace the ontogenetic history- of each element m the floor of the ventricle and in this way homologize the structures in the basal part of the mammalian interbrain with those in the same region of the selachian brain.

A reconstruction model of the ventricular floor of the adult ilomestic cat shows the followhig recesses and emuiences, enumerated from the optic chiasm caudad toward the mamillary body.

Accessory recess Surface eminence

Recessus praeopticusl . . crista supraoptica

Recessus intraopticusj

Recessus tuberis eminent ia sacrularis

Recessus infundibuli infundibulum

Recessus processi infundibuli processus infundibuli

Recessus premaniinillaris eminent ia premammillaris

110 AMERICAN ASSOCIATION OF ANATOMISTS

Several eminences appear on or adjacent to the floor, but contain no recesses. They are the emincntiao hiterales (protuberant lateral portions of the tuber cinereum) the corpora mammillaria and the interpeduncular ganglion.

The develo])inent of all of the above structures depends upon changes in three distinct areas of the interbrain. As thej^ appear in the 19 somite cat embryo these areas are the hypencephalon of Kupffer, the primitive optic groove and the lamina terminahs. The more important changes occur in the hypencephalon. This region in the 4 mm. embryo (about 26 somites) is divided by a ridge in such a way as to form a dorsal and a ventral sac.

\'on KufTper has sho"SATi similar sacs in the development of selachians, ganoids, teleosts and amphibians. Corresponding evaginations have also been observed in the hj-pencephalon of sauropsids. In fish the dorsal sac gives rise to the posterior lobes, while from the ventral sac arise the inferior lobes and the saccus vasculosus.

In the 10 mm. cat embryo two small evaginations have made their a])pearance dorsal to the dorsal sac. The more ventral of these two evaginations becomes the corpora mammillaria, the more dorsal, the ganglion interpedunculare.

Later stages in the development of the cat up to 70 mm. shows that the ventral sac gives rise to saccular eminence, inf undibulum and infundibular process. From the dorsal sac develops the praemammillary eminence. This latter eminence is a conspicuous' feature of the floor of the third ventricle in such forms as the hon, grizzly bear and leopard. It is present in all the mammals examined by the writer and, although somewhat obscured in the adult human brain, is well marked m the child.

The evidence presented seems to justify the following homologies:

Mammalian brain Selachian brain

Eminentia saceularis lobi inf eriores

Infundibulum and processus infundibulum saccus vasculosus

Eminentiae laterales lobi laterales

Eminentia praemammillaris lobi posteriores

The intraoptic recess which communicates with the third ventricle and extends for a considerable distance through the optic chiasm into the optic nerve is the remnant of the primitive optic recess. Its clinical significance in its possible connection with choked disc due to increased intra-cranial pressure is, at least, suggestive. This problem will require further observations upon pathological material as well as experimental controls, the result of which \v\\\ be reported in a subsequent paper.

£4' On the so-called 'BuWar' portion of the Accessory nerve. D. Davidson Black, Anatomical Department, Medical School, Western Reserve University

The following observations have been made from a series of transverse sections through the medulhi and upper three cervical segments of a new-bom balje, prepared by the pyridine Cajal method of Ransom.

PROCEEDINGS 111

This series represents a part of the material prepared in the course of a study of the calamus region which is as yet incomplete. However, certain facts bearing upon the relations of the so-called 'bulbar portion' of the nervus accessorius have been noted. These are of interest when contrasted with the usual description of the origin and relations of this structure obtaining in current texts.

The origin of the spinal portion of X. XI has been definiteh' established and can be made out quite well in this series. The nucleus occupies a central and somewhat lateral position in the anterior horn in the cord, and extends upwards into the medulla to about the level of the lower third of the pjTamidal decussation. The cells are of tj^pical somatic type, and the emergent fibers pass to the periphery in the well known geniculate manner, so that in no transverse section is the whole course of these fibers displayed.

The ventro-mesial cell group of the anterior horn may be traced as a practically uninterrupted column into the hypoglossal nucleus.

Laterally the cells of the anterior horn become scattered, and lose their characteristic grouping when traced into the formatio reticularis of the medulla.

There is a very apparent interval between the cephalic extremity of the cervical accessory nucleus and the caudal end of the ambiguus cell group.

The dorsal nucleus of the vagus may be traced as a verv^ distinct cell column almost to the lower end of the p\Tamidal decussation. In other words, this nucleus overlaps that of the accesson,- nerv^e in the lower medulla.

There is thus a space between the cephalic extremity of the nucleus of the accessory nerve in the cord and the lower end of the cell group usually described as giving rise to its bulbar fibers, namely, the nucleus ambiguus.

In the interval, in the series described, there are numerous fibers to be seen taking their origin direct in the dorsal nucleus of the vagus, and passing to the periphery ventral to the substantia gelatinosa Rolandi. In their emergent course these fibers arc cur^-ed laterally and caudally so that in a transverse section their whole extent is not seen. These fibers presumably make up the caudal portion of what is usually described as the bulbar part of X. XI.

At a higher level, where the nucleus ambiguus becomes definitely recognizable, fibers arising from this source take the well known indirect course to the periphery, joining on their way fibers from the dorsal vagal nucleus, and passing ventral to the substantia gelatinosa Kolandi. This last point is tiie only one in which these fillers ditYer from those usually described as giving rise to the vagus projior.

(Conclusions: (1) There is no morjihological ground for the consideration of the bulbar XI apart from the vagus in the si>ecimen I have studied; its nucleus of origin is but the caudal jirolongation of the dorsal vagal nucleus. (2) That Kolliker's distinction between the emergent fibers of the bulbar XI and those of IX and X. leased on the observations

112 AMERICAN ASSOCIATION OF ANATOMISTS

that those of the former i)a.^s out ventral, wliile the hitter pass through or ilorsal to the substantia gehitinosa ]{()hin(H. is without significance. (3) The extent of the vagal and accessory nuclei corresponds practically to Kai)pers' findings in Dideljihys.

In view of the recent investigations of \'an Gehuchten, Molhant, Raiison, Kappers, ]\Ialone and others, together with the above oljservations, would it not be better to consider this structure as part of the vagus projier and restrict the term nervus asccessorius to the present spinal portion of this nerve?

Discussed by Streeter.

25. Further observations on the sound-transmitting apparatus in Uro rff'/fN'. H. D. Reed, Zoological Laboratory, Coniell University.

In 1909 Kingsbury and Reed' jmblished a paper in which they stated that tN-pically the somid transmitting apparatus in Urodeles is composed of two elements appearing at different ages of the individual and differing in origin. The element which they called 'columella' is the first to arise during develoj^ment and is wholly extraotic in origin. It appears as a cord of cells which is comiected from the very outset with the squamosum. The ventral end of the cord reaches the middle of the fenestra vestibuli where it spreads out into a broad plate which becomes jointed to the fenestral membrane. The other element called 'operculum' does not arise until just before transformation. It is otic in origin since the major part, at least, is cut out from the walls of the ear capsule caudad of the foramen. It acquires connection with the suprascapula through the M. opercularis. After the operculum arises the columella fuses to a greater or lesser extent with the cejihalic lips of the fenestra but retains its connection witli the suspensorium through the stylus and its ligament.

Certain forms, as for example Triton, Diemictylus, the Plethodontidae Desmognathidae and Amphiumidae, were found to ])ossess but a single (.'lement in the fenestra vestibuli. In Triton and Diemictylus this element possesses the connection with the suprasca])ula through the M. opercularis and in every respect of structure and relations 't is identical with the ojjerculum of the typical forms and develo]iment shows this to be true. The columella very early in larval life fuses completely with the cephalic lips of the fenestra.

In the rietliodontidac, Desmognathidae and Am])hiumidae the smgle fenestral element has the structure and relations of both columella and operculum. The ce])halic portion of the ))late possesses a stylus which is connected vnth the suspensorium while in the caudal portion is found the perilymphatic prominence \\'ith a muscle extending to the sujirascapula. The cephalic part of tiie plate is always fused at its ventral angle with the lips of. the fenestra.

' H. I'\ KinKHl)iiry and II. D. Uecd. Tlit- coluinella auri.s in Anipliibia. .lour. Morph., vol. 20, H»0<), |)p. r)4(>-r>2S.

PROCEEDINGS 113

The natural inference is that the single element in these forms represents a fusion of the two elements, columella and operculum. A study of complete developmental stages shows that this is true but the greater part of the fenestral plate represents operculum or at least tissue which is otic in origin.

A brief description of the development in Spelerpes bi.slineatus will illustrate the conditions in all. The fenestra in Spelerpes is morphologically larger than in Ambystoma since it represents both the primary and secondary- fenestrae of that form. The columella arises in the typical fashion but instead of spreading out to form a plate which fits into the fenestra it remains as a cylinder of cells extending horizontally across the fenestral membrane and when fully chondrified does not increase in size or in any way spread out upon the membrane. The connection with the ear capsule is very early estabUshed by theupw^ard growth of the lips of the fenestra. In the caudal portion of the fenestral membrane which corresponds in relative position to the operculum of Ambj-stoma separate centers of chondrification arise and through groT^-th eventually meet. In this way there is formed a sieve-like plate which fuses ^\^th the extraotic rod of cells. Later it becomes completely chondrified. The fully formed plate, therefore, represents two elements, which, while fused in the definitive structure, are distinct in their origin. The extraotic rod of cells becomes the stylus of the fenestral plate and constitutes the representative of the columella in these forms. The fenestral plate, while in no part is cut out from the ear capsule, is otic in origin and to be regarded as the equivalent of the operculum.

The conditions as described above in Spelerpes are those which prevail in the Desmognathidae and Amphiumidae in all of which a single fenestral element is present. Siren possesses but a single fenestral element which is lacking in both suspensorial and shoulder girdle connections. The need of developmental stages for study leaves the nature of the plate unsettled.

26. The tendency toward adjustment of posture in transplanted labyrinths, G. L. Streeter. University of Michigan (This paper \\-ill be printed in full in The Journal of Experimental Zoolog\', vol. 10. 1914).

27. On the development, attachment and action of the teciorial membrane. Irvixg Hardestv. Tulanc University.

The begimiing of the tectorial membrane ajipoars m foetal pigs of 3 to 5 cm. long as an imperfectly fibrous, transparent film lying iijx)n and produced by a thickening of the epithelium of the foetal cochlear duct along its axio-basal aspect. This b;md of tlucker epithelium l>ecomes the greater epithelial ridge" of the later stages.

In foetuses of 6 to 9 cm., the greater ridge has become thicker and* broader ami appears only in the l>ase of the cochlear duct, due to the invasion of its axial side i)v the mesencylunal s>iicytium to form the vistibular lip of the spiral lamina. As this invasion proceeds, the :L\ial cells cease to prothice tectorial membrane and tiuis thr axial edge of the

THK ANATOMIC.U. RECORD. VOL. 8, NO. 2

114 AMERICAN ASSOCIATION OF ANATOMISTS

nu'iul)raiu' remains thin and is licld adherent u])on the vostil:)ular Yip. The now thicker film ujwn the greater ridge shows structure characteristic of the tectorial memlirane. At the extreme lateral or outer margin of the greater ridge there is differentiating a line of cells, 2 or 3 wade, which cells are hroader than tiieir neighbors and when traced through the later stages heeome the rods of the organ of Corti, these cells and a few others about them increasing in height to from the "lesser epithelial ritlge" (anlage of the organ of ("orti) lateral to the greater ridge and tectorial nu'mbrane.

The greater ridge increases in both width and thickness, acquiring its maximum width in foetuses from 13 to 16 cm. Its cells are steadily contributing thickness to the basal side of the tectorial membrane, comiected with it by 3 to 6 delicate fibers continuous from the distal end of each cell. The lateral or outer edge of tlie tlevelojiing t( ctorial membrane here conforms closely to the rounded lateral margin of the greater ridge, cu]5i)ing around this margin and fitting into the groove iietween it and the lesser ridge, the basal cells of this rountled margin coming to lie at almost right angles to the axis of the cochlea in order to i)e peri)endicular to the edge of the membrane they are forming.

During the earlier stages of their differentiation, the cells of the lesser ridge (beginning organ of Corti) like\\ise produce a few filamentous threads and these; threads are seen extending from their cells of origin and adhering to tiie vestibular surface of the outer edge of the developing tectorial membrane. These threads disintegrate in the later stages and thus contribute no ])art of the adult tectorial membrane. In structure, the tectorial meml)rane consists of a hyaline matrix, jjrobalily keratin, in gelatinous form, in which ar(> imbedded the very numcn-ous fine fibres or threads of uniform size, the varying directions of which are determined by the varving directions of the cells producing the membrane during the different stages of the increase and decrease of the greater ridge. The filaments j^roduced l)v the cells of the early lesser ridge have ceased to grow in jiigs of 1() cm., are never embedded in a matrix as are those of the tectorial membrane, are largely di.sintegrated at 19 cm., and have totally disajipeared in foetuses near term.

In jiigs from 13 to 10 cm. the cells forming the axial side of the greater ridge begin to decrease in height and number. Beginning at this axial margin, the cells gradually become divorced from the membrane they have produced, the process of divorce proceeding outwardly, the divorced cells receding and decreasing in number till they become the fewer, flattened cells lining the .spiral sulcus of the adult. The last cells to l)ecome separated from their iiroduct are thus those immediately adjacent to the inner sustentacular cells of the organ of ( 'orti. The recession and decrca.se in number is accom])anied by an a])i>reciable narrowing of the basal floor of the spiral sulcus. In foetuses of 15 cm., the width of the greater ridge may measure in the ai)ical coils of the cochlea twice the width of the basal floor of the spiral sulcus in the adult. In the ba.sal coil this decrea.se in width is only about one third of the width at 15 cm.

PROCEEDINGS 115

This developmental decrease of the distance between the orj^an of Corti and the vestibular lip of the spiral lamina results in the change in position of the organ of (.'orti with reference to the t\Tnpanic surface of the tectorial membrane and, of course, in a tearing free of the membrane from any attachment it may have with structures lateral to the vestibular lip of the spiral lamina. In the apical coils the membrane of the adult may come to extend not only over the entire organ of f'orti but also over from 9 to 13 of the cells of Claudius. Thus the tectorial membrane is only attached along its axial edge upon the vestibular lip of the spiral lamina. Its outspanning portion is of necessity free.

From various measurements taken from 9 growth stages and from the adult, the most probable explanation of the final position, well under the tectorial membrane, acquired })y the organ of Corti is that it is due to a groAvth in width of the vestibular portion of the spiral lamina resulting in an outer or lateral projection of the membrane over the organ, and in greater part to an actual shifting axialward of the organ of Corti coincident with the disintegration of the greater ridge.

In the adult ])ig the tectorial membrane is about 30 mm. long. In the apical turn it is about 5 times as wide and 5 times as thick as is its basal end; its area in section in the apical turn is approximately 21 times and its volume 95 times the area in section and the volume of its basal end.

Teased fresh specimens of the tectorial membrane show that it decreases evenly from its larger, apical towards its smaller l^asal end and it has sufficient elasticity, probably due to the arrangement of its fibers, to maintain its position over and approximate to the organ of Corti. Longitudinally it is exceedingly flexible, offering practically no resistance to stress applied transversely to its long axis.

An apparatus constructed to simulate the essential parts of the auditory apparatus is thought to indicate something of its functional action. The external meatus is represented by a large mouthed megaphone over the smaller end of which is stretched a piece of gold lieater's skin for the tympanic membrane. The cochlear duct is a narrow. thick-walle<l box, 42 inches long, with a wooden spiral lamina and thin wooden l)asilar membrane and with drum-skin covered ojienings rejiresiniting the fenestrae, at the basal ends of the scalae. The tectorial meml)rane is represented by a i)iece of very thick elk's hide pared to the shape and approximate i)ro]:)ortions of the membrane and softened, and its thin edge affixed uiion the vestibular lip of the s])ir;U lamina. At 6 equal intervals fine platinum wires are jiassed througii the membrane to make contact below witii small copjier jilates re])resouting the organ i>f Corti. the ])lates being continuous with wires and ca])able of being raised or lowered by means of adjustment screws Inuieath tiiebox. Batteries are connecttnl with tiie i)latinuni and copjier wires at each interval. The box, wiiich has a water-tight, glass top, is comjiletely filUnl witii ilistilled water, the top fastenc^l down without hiclusion of air, and a rejiresentative of the ossicles is i)laced pressing b(>twtM'n tiie tympanic niemlirane and the skin rejiresentijig the fenestra ovalis. Telephones are interposed in the circuits made by contact of the jilatiTUun wires with the copjxT plates.

11(3 AMERICAN ASSOCIATION OF ANATOMISTS

Ordinary organ roods, having kno\Mi vibration frequencies, were used chiefly in the oxijoriments. Tliese were sounded into the megaphone. It was found that any viljration from a stop upon the laboratory floor up to the note G below 'middle C" (196 vibrations per second) would throw the membrane into vibration throughout its entire length. This note caused the membrane to vibrato more strongh^ at the fourth inter\'al from its smaller end than at any other inters-^al, indicating a certain amount of resonance in this region. A, the next note above, produced vibrations at all intervals of the membrane except the sixth, the apical end. Middle C, 2(31 vibrations per second, was damped out at the fourth interv'al. Notes above F, which is 349 vibrations per second, produced vibrations in no part of the membrane. Occasionally a note other than G produced more pronounced vibrations at a certain intorwal than at others but evidence of the existence of resonance were unsatisfactory. x

From results with this comparatively coarse and crudely constructed apparatus, it is suggested that notes up to a certain pitch throw the entire natural tectorial membrane into vibrations of corrresponding frequencies and that sensations of pitch are determined by the frequency of impingement of the membrane upon the auditor}^ hairs, intensity being determined by the amplitude and qualitj^ by the qualitrv of the wave motion imparted. Further, that the highest notes within the range of the auditory a])i5aratus throw, according to their frequency, only varying extents of the smaller, basal end of the tectorial membrane into vibration, being so damped out in passing toward the apex of the cochlea, overcoming friction, the inertia of the endolvinph and that of the membrane itselJf, as not to produce vibrations in the heavier, apical portions. Finally, since, if the tectorial membrane varying in mass as it does were cut into a number of segments, each segment would have a different natural vibration frequency, it is possible that it exercises a certain amomit of resonance. The diaphragm of the telephone possesses a small amount of resonance. The above results suggest a modification of the telephone theory of hearing.

Wednesday, December 31, 9.30 a.m. to 1.00 p.m. Session for

THE reading of PAPERS, PRESIDENT RoSS G. HaRRISON AND ViCE

President Thomas G. Lee, presiding.

28. Regeneration of medullated nerves in the absence of the embryonic nerve fiber following experimental non-traumatic degeneration. Elbert Clark, Hull Anatomical Laboratory, University of Chicago. In this study degeneration of the modullatod nerves was brought about in the domestic fowls by a ])rolong('d exclusive feeding of polished rice (finest fjuality of white table rice). There frequently resulted a pronounced paralysis of tlie logs which was always accompanied by marked degeneration in the medullatocl fil)ers of the sciatic nerve. Recovery of the fowls and regeneration of the nerves was accomplished by returning the fowls to an adequate nutritive diet.

PROCEEDINGS 117

In such fowls the nerve fibers are mtact during degeneration and all traumatic and infiamatory effect produced by cutting the tissues and the nerve or of tj-ing the latter are obviated; the process of degeneration can be stopped at almost any stage or greatly prolonged, and several stages of degeneration are to be observed in different fibers of the same nerv^e. In regeneration the possibility of an ingrowth o fibers from other nerves into the regenerating nerve under observation is eliminated and repair of the medullated nerves can be induced after any stage of degeneration.

Ten to twenty percent of the medullated fibers of the nervus ischiadicus showed a complete fatty change of their medullated sheaths into globules of degenerated myelin and a segmentation or granulation of their axis C3^1inders. No multiphcation of the nuclei of the neurile mm a sheath could be observed and consequently no "embrj'onic nerve fibers" or "Band-fasem."

During recovery these degenerated fibers attained new axis C3iinders and the medullary sheaths returned to normal. In other words, regeneration has been observed to follow degeneration in medullated ner\'e fibers without passing through the embrj'onic nerve fiber or Band-faser stage.

By prolonging the degenerative process there resulted a multiplication of the nuclei of the neurilemma sheath. This and other experiments tend to show that the embryonic nerve fiber may be coincident -sNith a late stage of degeneration. It may not represent an early stage of regeneration and its presence does not signify an attempt at regeneration on the part of the medullated nerve fiber.

In the absence of the embryonic nerv'e fiber, the degenerated myelin was absorbed with extreme slowness, persisting as droplets after one 3'ear and fourteen days. On the other hand, where the embryonic nerve fiber was formed the degenerated myelin quickly disappeared from the fiber. The conclusion is reached that the proliferating nuclei of the neurilemma sheath participate in the resorption of the degenerated myelin.

In regeneration a new axis cylinder was attained by outgrowth and in the absence of the embryonic nerve fiber. The new axis cylinder grew do^^T^ the old medulary sheath which latter still contained large globules of degenerated myelin and fragments of the old axis cylinder. The outgrowing axis cylinder was seen to brimch, and in cross-sections of the n(Tves two new axis cylinders were obsers-ed ^\^thin the same old medullary sheath. The embryonic ners'e fiber could, of course, play no part in the formation of the new axis cylinder, either by autor^eneration or l)y outgrowth.

No indications of regeneration were observed in the fibers of the spinal cord.

Discussed by Sheldon.

29. Some changes in the mrvou.'^ system of the metamorphosing tiulpoles of Rana pipiens. Elizabeth H. Dunn, Woods Hole, Miiss.

118 AMERICAN ASSOCIATION OF ANATOMISTS

30. The development of the cranial si/nipath^'tic (jancjUa. A comparative

studij. Albert Kuntz, 8t. Louis rnivcrsitv School of Medicine.

Tlie oliservations on wiiich the followiufi; conchisions resardinf; the development of the cranial syni))athetic f^anjilia in fishes are based were made on i)re)iarations of embryos of the common toad fish (Opsanus tail.) The .>^ix symiiathetic fianglia on the cranial portion of the s>Tnpathetic trmik are genetically related to the I sjiinal nerve and the X, VII, and \' cranial nerves. The majority of the cells giving rise to these ganglia are derived directly from the I spinal ganglion and the cerebral ganglia associated with the X, \TI, and V cranial nerves. Certain of these symixithetic ganglia receive cells also which advance perijiherally from the wall of the neural tube along the fibers of the motor nerve roots. The ciliary ganglion arises in the path of the oculomotor nerve. It is derived primarily from cells which advance peripherally from the wall of the mid-braui along the fibers of this nerve. As development advances the ciliary ganglion becomes connected with the Gasserian ganglion and the first sympathetic ganglion associated ^\^th the latter, through the radbc ciliaris longa. After this connection is established, a relatively small number of cells which wander out from the Gasserian and the first sympathetic ganglia are, doubtless contributed to the ciliary ganglion.

In larvae of Amblystoma and Rana the ciliary ganglion bears the same genetic relationship to the oculomotor nerve and arises in essentially the same mamier as in embryos of Opsanus. The cranial division of the sympathetic nervous system is relatively feebly developed in the Am])hibia. The ciliar\' ganglion is relatively small in the larvae of both Am})lystoma and liana. Other distinct sympathetic ganglia probably do not occur in the crainal region in these types of Amphibia. However, sympathetic ganglion cells are incorporated in, or associated with, certain of the cerebral ganglia.

In embr\'os of the turtle, the cilary ganglion arises at i\w growing top of the oculomotor nerve. The majority of the cells which take part in the development of this ganglion h:ive their origin in the wall of the mid-brain and advance peri])iierally along the oculomotor nerve, or are the direct descendants of such cells. As develo]iment advances, the ciliary y;anglion l)ecomes connected by a fibrous ramus with the ophthalmic division of the trigeminal nerve. After tiiis connection is established, a relatively small number of cells which advance peripherally from the Gasserian ganglion are contributed to the ciliary ganghon.

The sphenopalatine ganglion arises, in embryos of the turtle, in the path of the great supcTficial petrosal nerve and soon becomes connected by fibrous rami with the maxillary division of the trigeminal nerve. It is derived from cells which advance ])eri])herally irom the geniculate ganglion and the Gasserian ganglion r(\s})ectively ahmg the great superficial petrosal and the maxillary nerves.

(ianglia homologous with the otic and the submaxillary ganglia of the higher veiieljrates were not observed in embryos of the turtle.

PROCEEDINGS 119

In embryos of the chick the cihar}^ ganglion bears the same genetic relationships to the oculomotor and the ophthalmic nerves and arises in essentially the same maimer as in embryos of the turtle.

The otic ganglion arises, in embr3^os of the chiek, in the path of a tract of sympathetic fibers which emerge, at the level of the geniculate ganglion, from the sympathetic plexus surrounding the carotid artery and continue cephalad. It is derived primarily from cells which advance cephalad from the superior cervical ganglion and cells which wander out from the geniculate ganglion.

In proximity wHh the olfactory epithelium, in embryos of the chick, is located a relatively large ganglion which is primarily related to the great superficial petrosal nerve, but has fibrous connections also with the maxillary nerve. This ganglion, described by Rubaschkin' as being related to the trigeminal nerve, is probably homologous \vith the sphenopalatine ganglion of the turtle. It is derived primarily from cells which advance peripherally from the geniculate ganglion along the great superficial petrosal nerve, but probably receives cells also which advance peripherally from the Gasserian ganglion along the maxillary nerve.

The relatively small submaxillar}^ ganglion, in the chick, is genetically related to the mandibular nerve.

In embryos of the pig, as the writer has shown in an carher paper,^ the ciJiary ganglion is geneticalh' relatetl to the oculomotor and the ophthalmic nerves, while the sphenopalatine, the otic, and the submaxillary ganglia are genetically related primarily to the maxillary and the mandibular divisions of the trigeminal nerve.

The results of a comparative study of the development of the cranial sympathetic; ganglia in embrj^os of tj^pes of the several classes of vertebrates, as above set forth, warrant the conclusion that during the process of evolution the sources of the majority of the cells giving rise to the cranial sympathetic ganglia have become shifted cephalad. Whereas, in the lower vertebrates the cranial sympathetic ganglia are genetically related to the cervical sym]iathetics, the first spinal nerve:?, and the X, IX, VII, V, and III cranial nerves, the great majority of the cells taking part in the development of these ganglia in the mammals are derived from the Gasserian ganglion and the wall of the mid- and hindbrain via the oculomotor and the several divisions of the trigeminal nerves.

31. The tract of Lissaucr in the Rhesus monkey. S. W. Raxsom, Northwestern University Metlical School. The observations which I siiall report were madt^ on pyridine-silver

and Pal-Weigert jirejiarations of tiu^ spinal conl of the Hliesus monkey. In a Pal-Weigert i)reparation of the fifth corvical segment the tract

of Lissauer is located in the apex oi the columna jiosterior just lateral to

' Aimt. Anz., Hd. 31.', pp. 497-5ir>.

^ Tlie development of the cranial sympathetic ganglia in the pig. Jour. Comp. Neur., vol. 23, pp. 71-9G.

120 AMERICAN ASSOCIATION OF ANATOMISTS

the cntcrinp; fibers of the dorsal root. In comparison to the rest of the sul)stantia alba the tract is lightly stained. It contaias rather ^videIy seiiarated fine meduUated fibers. Most of these fibers run longitudinally in the tract but some run across.it from the dorsal root to the substantia gelatinosa Rolandi. Some medullated fibers enter the tract from the lateral portion of the dorsal root; but a study of the literature makes it clear that many of the medullated fibers in the tract are of endogenous origin.

In a pjTidine-silver preparation of the seventh cervical segment the darkly stained tract of Lissauer fills the apex of the columna posterior and reaches from the suljstantia gelatinosa to the surface of the cord. An accumulation of subpial neuroglia is seen at the dorsal extremity. A neuroglia septum extends into the cord, separating the tract in question from the cerel)ellospinal fasciculus. The septum does not, however, reach the gray substance, and ventrally to it the tract of Lissauer spreads out into the lateral funiculus upon the lateral surface of the columna posterior. It goes over gradually into the fasciulus proprius of the lateral funiculus.

\\'hc.n one compares the number of medullated fibers seen in a Pal^^'eigert preparation with the number of axons seen in pyridine-silver })reparations it is obvious that the non-medullated fibers of this tract far outnumber those which are medullated.

The medullated fibers of an entering dorsal root pass over the tip of the tract into the cuneate fasciculus. The non-medullated fibers of the root separate out from among the medullated fibers before the root enters the cord and form a well defined lateral bundle. This lateral part of the entering root, consisting of non-medullated and a few fine medullated fibers, turns forward into the tract of Lissauer. This shows that the non-medullated fii)ers of the dorsal roots do not run \vith the medullated fibers into the fasciculus cuneatus but run in Lissauer's tract.

There is a very close relation between the tract and the substantia gelatinose Rolandi. This substance contains many small nerve cells and non-medullated fibers. There is a constant interchange of fibers between it and the tract of Lissauer and everything points to it as the nucleus of reception of the non-medullated fibers of the tract and therefore also of the non-medullated fibers of the dorsal roots.

In conclusion it may be said that tiie tract of Li.ssauer in the monkey, like that in the cat, is composed chiefly of non-medullated fibers. These represent the intramedullary continuation of the non-medulalted fibers of the dorsal roots and probal^ly terminate in the substantia gelatinosa Rolandi.

Discussed by Sheldon, Hardesty and Hubcr.

PROCEEDINGS 121

32. Chorionic ducts and intra-chorionic cysts in young human embryos. Frederic T. Lewis, Harvard Medical School.

33. Further observations on the supports of the rectum. T. Wixgate Todd, Western Reserve University, Cleveland, Ohio.

In a previous paper (The anatomy of a case of carcinoma recti, Annals of Surgery, 1913, vol. 59, pp. 831-837) the speaker indicated the clinical significance of the follo^vdng structures: (Ij The function of the fascia propria of Waldeyer (recto-sacral aponeurosis of J. W, Smith) in making the rectum a self-contained organ; (2) The function of the lateral hgaments (les ailerons) as supports of the rectum; (3) The fact that the lateral hgaments arc mainh^ formed by the perineural tissue around the sacral nerves supplying the rectum, but also include the perivascular tissue around the middle haemorrhoidal vessels.

In the present communication the speaker first postulated that only the type of rectal prolapse which commences at the anal margin should be retained under the heading of 'prolapse;' the other varieties being in reality types of intussusception.

After a consideration of the various factors suggested clinically as causes of prolapse in infants, evidence was brought fon\-ard in support of the following contentions: (1) That the relative proportionate length and extensibility of the lateral ligaments in the infant at birth are approximately the same as in the adult. (2) That there is no 'laxity' of the lateral ligaments. (3) But that the rectum is already a peh-ic organ at birth while the bladder and uterus lie at a higher level. (4) That in consequence of the relative low position of the rectum and of the fact that it is not shielded by an overhanging sacral promontory, the organ is in a position of greater mechanical disadvantage in infancy than in adult life. (5) Hence in infants if the pelvic cUaphragm he weak, as in rachitis, there is every possibility of the occurrence of a temporary and limited procidentia of the rectum which does not require any operative measure for its treatment.

34- On the occurrence of fat in the muscle fibers of the myocardium and of the atrio-ventricular system. H. HaysBullard, Anatomical Laboratories, School of Medicine, Universit\^ of Pittsburgh, Pittsburgh, Pa. In former papers ('12) I have presented data which indicate that the commonly accepted belief, to the effect, that microscopically \'isible fat does not occur m normal cardiac musele fibers, has arisen largely from the fact that the techinquo for fat demonstration, as usually employed is inadequate to show tlie normal fat content of muscle fillers. It is only l)v using sjiecial metliods upon fresli tissue that tiie full fat content is (iomonstrated. Fresh material is necessary, for fats are unstable comjKnmds, as is now recognized in' chemists but too frequently overlooked by histologists. For the demonstration of the fat content of muscle fibers and other tissues, Herxheimer's Scharlach R method offers mark.ed advantages.

Boll ('1 1-'12) usingthe Herxheimer method, has shown in a remarkable series of feeding experiments that t\\v ' liposoine' content of skeletal mus

122 AMERICAN ASSOCIATION OF ANATOMISTS

c-le and of cardiac muscle is inHiienccd l)y the diet of the animal. He Ih'Hcvcs that some of the iii)S()mes' are fat droplets, while others are fat mixed with some substance other than fat. He finds that starved rats show few 'liposomes' in the striated muscle, while those which have been on a diet rich in fat show a marked increase in the 'liposome' content of the muscle fibers.

Emjiloyinp; the Herxheimcr method together with other methods, during; i\w ])ast several years. I have examined the cardiac muscle of more than a hundred animals for the j^resence of microsco])ically visible fat. In about forty hearts, the muscle fibers of the atrio-ventricular system were also examined. The animals included the mouse, rat, cat, dog, o}:»ossum, sheep, jjig, ox, monkey and man. The results of this study, as here summarized, are later to be set forth in greater detail.

Normal cardiac muscle fibers of mammals contain a varying amount of fat in the form of droplets which react to fat stains and can be demonstrated microsco])ically. The droplets of fat are arranged in rows between the fibrillae or muscle columns and in the central peri-nuclear sarcoplasm. In size the drojilets vary from 8 or 4 micra to the limit of microscojiical vision. In some animals the fat is uniformly distributed among the muscle fibers, each containing api)roximately the same amount; on the other hand, there are often two general types of fibers, one ty]3e is heavily charged with fat, the other tj'pe containing little. The fibers w^hich contain the large amount of fat correspond to the well known "dark fibers" of skeletal muscle, while those which contain little correspond to the light fillers.

During the later weeks of f(^tal life fat is normall}' present in the cardiac fibers (man, ox, ])ig, cat, dog). Earlier stages were not examined.

The normal fat content of cardiac muscle is not a product of degeneration, i)ut is brought in to the fiber to serve as a source of energ\' and food. The (juantity of fat in cardiac fibers is decreased in starvation and increased w'hen the animal is kept on a fat diet.

Cardiac muscle fibers contain many granules which, after ai^iiropriate fixation, may be stained by the mc^thods of Altmann, Benda, Weigert (modified) and Heidenhain. These granules are the true interstitial granules of Kolliker, l)iobIasts of Altmann, chondriosomes of Regaud, and Q granules of Holmgren. Granul(\s of this ty]ie cannot l)e stained by fat .stains and are not fat, although there is .some evidence to show that they contain an albumino-lipoid.

Little fat is normally ])resent in the muscle fibers of the nodal tissue of the heart or in the .stem of the bundle of His, even when the myocardial fibers are crowded with fat. Typical Purkinje fibers of the .sheep, pig and ox, contain a small (juantity of fat but the amount is increased as the fibers take on cardiac character. More fat is ])resent in the i'urkinje fibers of species such as man, dog and cat, in which the Purkinje fibers are hi.stologically similar to the cardiac type.

Literature cited: K. T. Bell, 1911, Internat. "Monatschrift f. Anat. u. Phys., Bd. 28, 8. 297-347; iyr2, Journ. Path, and Barter., vol. 17, pp.

PROCEEDINGS 123

147-158. Also H. Hays Bullard, 1912, Journ. Med. Research, vol. 27, pp. 55-65; 1912, Amer. Jour. Anat., vol. 14, pp. 1-46.

35. Marchi technique: safer and easier clearing and mounting of sections.

H. S. Steensland, From the Pathological Laboratory of S>Tacuse

University, Syracuse.

This communication is presented on the assumption that clearing Marchi sections in chloroform is generally regarded as the best technique at the present time. It is generally recommended that Marchi sections be cleared in chloroform and mounted in chloroform balsam because xylol and other clearing reagents, and xylol balsam, cause the black osmic acid staining of fat to fade. Clearing in chloroform, as recommended, presents certain wellknown difficultities in technique. These difficulties sometimes make the fate of valuable material uncertain, for example, material that has been obtained as a result of painstaking and time consuming experiment.

Obviously it would be a great advantage if jNlarchi sections could be cleared in oleum origani cretici. Most of the d fficulties would be overcome. There would be no danger of drying and shriveling of the sections. The sections could be thoroughly blotted and flattened v\ith smooth (not embossed) filter paper. The chloroform l^alsam could be carefully applied. The retraction of the balsam from a part of the space between the coverslips and the slides would be practically done away with. It would he possible to turn over valuable material to a technician for clearing and mounting with much less fear of loss of material and >Aithout placing undue responsibility and strain upon the technician. When a large amount of material is to be handled it could be handled with much less strain and exhaustion. Large sections would be more safely handled, which is of special importance when the tissues involved are cut into serial sections.

Ten years ago in the Pathological Laboratory of Syracuse University there were mounted a considerable number of Marchi sections. The technique made use of was the usual technique except that the sections were cleared in oleum origani cretici instead of chloroform. At the present time I have been unable to find any evidence of fading after comparison with control sections made from the original lilocks of tissue. The control sections were cleared in chloroform and mounted in chloroform balsam according to the prevalent metiiod.

In order to put the matter to a further test some of the newly cut sections were placed in a dish of oleum t)rigani cretici. At intervals sections from the disii were mounted in chloroform balsam. No evidence of fading was found after ten days in the oil.

Oleum origani cretici is tiuis t'vidently a very much safer and easier clearing reagent than chloroform to use in the JNlarchi technique.

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36. Technical experiences: (a) Cataloguing lantern slides; (b) Permanent dry-mounts of the laryngeal cartilages; (c) The use of large tissue sections for demonstraiion purposes; (d) Degreasing bones. G. L. Streeter.

(a) Cataloguing lantern slides. A fairly good print of a lantern slide may be obtained by laying the finished lantern slide directly on blue print paper and printing either in the sun or before an arc light. Such a print plainly shows the subject and character of any ordinary lantern slide. This fact may be utilized in cataloguing lantern slides. By lirinting ones whole collection in blue print paper and mounting these prints in a loose leaf note book it makes it possible to look them over quickly for ascertaming what slides are in the collection and their respective number. The ^^Tite^ prints sLx slides at one time in an 8 X 10 printing frame on uniformly cut sheets. These sheets are then assorted more or less according to subject. On each picture the slide number is ^^Titten in and any other desired memoranda. The slides themselves are numbered and filed in the order of acquisition.

(b) Mounting laryngeal cartilages. A permanent and convenient mount of the lar\iigeal cartilages and adjacent rings of the trachea may be made by dehydrating the cleaned cartilages in alcohol, transferring them into xylol and then saturating them with melted parafin. Such cartilages are easily mounted on a base by means of metal adjustable standards and are durable enough to be trusted in the hands of students as demonstration specimens. The disadvantage of the usual dr>' preparation of the lar>-nx hes in its tendency to shrink. This is largely avoided by the above method in which the natural moisture of the specimen is replaced by parafin. In the process of dehydration there is some danger of warping the cartilages, but this can be prevented by cutting out little wooden forms to which the cartilages are tighth' laced with thread, or by fitting them over or between tubular bottles of different sizes. They should be kept on these until they come out of the melted parafin. In the six preparations we have made at Ann Arbor we included the hyoid bone. The preparations show an interesting variation in the form of the cartilages and in the character of their ossification, so much so as to warrant the increase of our collection for the study of these particular features.

(c) Demonstrntion sections. We have found in our laboratory that large stained celloidin sections mounted and projected like lantern slides form an excellent means of demonstrating certain features in regional and macroscopic anatomy. It may be suggested that where successful preparations of this kind are obtained there would be an advantage in cutting extra sections and saving them as duplicates to be exchanged for similar preparations from other laljoratories. The folk^N-ing sections, which had been prepared in the al)ove manner, were <lemonstrated ^\^th the lantern: (a) Transverse section through top of adult head showing layers of scalp, formation of cranial vault, dura, falx cerebri, superior longitudinal sinus, together with the bra'ui and the membranes directly covering it; (b) Cusp of adult semilunar valve,

PROCEEDINGS 125

flattened out to show distribution of connective tissue and formation of lunulae; (c) Transverse section through adult cavernous sinus; (d) Frontal section through adult larj-nx sho^\'ing false cords cut transversally and vocal hps together with cartilages and musculature; (e) Sagittal section through the adult temporomandibular joint; (f) Transverse section of adult penis; (g) Transverse section through neck of new-bom babe showing especially the distribution of fascia ; (f) Sagittal section of finger of newborn babe showing metacarpal and three phalangeal bones with epiphyses, joints and muscle attachments.

(d) Degreasing bones. The bones of the extremities from fatty subjects may still have after maceratoin a large amount of fat in them. Most of this may be easily, economically and safely removed by placing them in a drying oven and sweating the fat out. A fatt\' femur after being in an oven at 110° C. for two hours loses 2.5 per cent in weight by removal of the fat. On coming from the oven the bones are briefly rinsed in cold gasoline and are then bleached in potassium permanganate followed by sulphurous acid. They are then ready for study. We have found that we can increase the durability' of fragil bones b}' immersing them in melted paraffin. This darkens the bone but does not interfere with its suitability for student use.

37. On the nature of fat cells. H. G. Weiskotten axd H. S. Steensland,

From the Pathological Laboratory of Syracuse University, S\Tacuse.

^\^len rabbits receive intravenous injections of maximal sublethal doses of saponin large territories of the marrow undergo necrosis. The parenchymal cells and fat cells soon undergo autolysis lea^•ing mainly the free fat droplets, originally contained in the fat cells, to represent the original architecture of the narrow. The fat droplets appear to remain largely in the original loci of the fat cells, in which they were contained.

Subsequently there occurs apparently complete regeneration of the marrow with the restoration of the original proportions of parench>-mal cells and fat cells. By examination of sections of the marrow from animals at various stages after injection it appears to be possible to determine the manner in which the fat cells are regenerated and to determine the nature of these fat cells.

To a large extent the necrotic tissue is invaded first by free endothelial cells. These cells tend to arrange themselves at the peripher>' of individual fat droplets and to fuse together into multinucleated c>-toplasmic masses, which envelop the fat droplets. These masses constitute the wellknowii foreign body giant cells. Subsequently a large part of the cj'toplasm of these cells disappears, the nuclei decrease in numl>or and the c\i;oi5lasm Ijecomes retluced to the thin envelope characteristic of the ordinary fat cell. In this envelope there j>ersist one or more nuclei, wliich become crescentic as the cytoplasmic layer becomes tliin, like the nucleus of the ordinar>' fat cell. The disappeanmce of nuclei evidently is brought about by a process of nuclear resor])tion or karyolysis.

One possibility that arises is that the fat cells originally do not become completely necrotic before the contained fat droplets become surrounded

126 AMERICAN ASSOCIATION OF ANATOMISTS

by forcipi hody piant colls: that the foreig:n body giant cells disappear jind then* remain the original fat cells.

In the manner described the fat cells are regenerated to a large extent before the parench>nnal marrow cells are regenerated Mainly after the fat cells are restored the hemoblastic centers develop in the corresponcfmg regions and the marrow is completely regenerated.

The concept that we wish to jiresent. on the basis of what has been described, is that fat cells are endothelial cells containing what may be called, by way of comjiarison, a physiological foreign body, namely fat. Ordinarily, in our experience, fat cells are regarded as mesenchymal cells or fii)roblasts or connective tissue cells in whose cytoplasm fat has been stored up.

In general, in many forms of lesion free fat occurs and is taken up by foreign body giant cells. This may be in situations in which fat cells are not normally' i^resent. In such cases the foreign body giant cells do not survive in the locus as fat cells, perhaps because fat cells do not normally exist in the locus.

That foreign body giant cells are formed as a result of the fusion of endothelial cells has been shown by the work of Mallory and his pupils.

38. The development of the septum atriorum. Robert Retzer, University of Chicago.

39a. The passage of the ovum through the uterine epithelium in Geomys hursarius, tvith demonstration of wax reconstruction^^. Thomas G. Lee, Institute of Anatomy, Universitj of Minnesota. Within the order of Rodentia there exists a greater variety in the implantation of ovum and formation of decidual cavity than in any of the other main divisions of the Mammalia. The rage of variation extends from those forms, like the rabbit, in which the whole of the uterine lumen is utilized, to that of mouse and rat, where only a restricted portion of the uterine cavity is transformed into a decidual cavity. Then follows tho.se peculiar form.s, as C'itellus (.spermophilus), in which the WTiter in 1902 and 1903 described for the first time a rodent in which the trophobla.stic layer of cells at close of segmentation caused the destruction of a small area of the uterine epithelium at the antimesometrial portion of uterine cavity, followed by an outgrowth of trophoblastic cells into the mucosa to form a nutrient organ, followed by the atrophy and disappearance of this organ upon the completion of the allantoic placenta at the mesometrial jwrtion of the uterus; the whole of the uterine cavity being utilized for a decidual cavity, as in the rabbit. And la.stly are found those forms in which, as in man, the ovum passes entirely through the uterine epithelium and a new decidual cavity is formed in the mucosa and independent of the uterine lumen. The first rodent of this type to be describerl was the guinea-pig, so beautifully worked out by ( Iraf Spec. . In ( leomys we find a second rodent of this tyjie, but with the following important points of difference from the guinea-pig which are shovx-n in the.se reconstructions. In the guinea-pig the ovum passes

PROCEEDINGS 127

through the uterine epitheUum at close of segmentation, and while it is very small in volume, the small perforation is quickly closed and the uterine ca\'ity completely separated by epithelium from the new decidual cavity. In Geomys, on the contrary, the ovum perforates the uterine epithehum in the blastula stage, and when of .so large a diameter that the edges of the large rounded perforation of the uterine epithelium camiot grow together as in the guinea-pig, or be filled with a fibrin plug as in man, this opening persi.sts during the entire preplacental period. The epithehum at the lip of perforation is somewhat everted and gives a point of attachment to a zone of the trophobla.stic layer of the blastocj'st. The dorsal portion of the trophobla.stic layer extends across the opening, and by this zonal attachment to the epithelial lip completely shuts off the uterine lumen from the new decidual ca^^ty. The cells of the mucosa are broken down and the decidual cavity is rapidly enlarged. The blastocyst sinks down into this cavity but continues to be suspended by the above described zonal attachment to the lip of the epithelial perforation. This zone \vi\\ ultimately form the outer margin of the allantoic placenta. A detailed description of the unique preplacental development in Geomys with plates will be published in the near future.

39b. An improved electric tnicrqscope lamp, with demonstration. Thomas G. Lee, Institute of Anatomy, University of Minnesota. This lamp was devised by the ^^Titer to meet the demand for a small compact and portable lamp for indi\'idual staff or student use in the Minnesota Institute of Anatomy, and has proved to be so satisfactorythat it is here demonstrated for the benefit of the members of the Association. The lamp consists of a .small vulcanite base fitted vriXh a silvered reflector and a socket into which can be screwed as desired either a 2, 4 or 6 candle-power Mazda lamp ^\^th miniature ba.se: a metal cap supported by 3 rods which fit into the base shuts off all side fight and gives the necessary ventilation. In the top of this cap is an opening the same size as the base of the Ai)l)e conden.sor. A device on the top of the metal cap holds in place over this opening the ordinary blue or ground glass plates commonly used with the Abbe condenson thus giving at all times monochromatic light of miiform inten.sity. The bai?e is fitted with flexible electric fixture ^^^re terminating in a small plug which fits into a socket in the table top. The entire lamp is small, about two inches in diameter and in height, so that it readily fits in under the Abl>e condenser when the mirror is jiusiied to one side. When not in use. the lamp can be put away in the student's lock<'r with the rest of his outfit. A stock automobile Mazda bull> of standanl make of volts. 5 watts, alternating current is used in this lamp. It is the smallest availal^le, the least expensive, and will withstand rough u.sage. In fitting up the lalxjratory tables a step down transformer is connected with the feed wire. This reduces the current used from 110 volts to (> volts. These transformers are small, inexjiensive, and can be had of any capacity desired, are used in the tradt- in sign-lighting apjiaratus. The wires leading from trans

128 AMERICAN ASSOCIATION OF ANATOMISTS

former are run underneath the tables and connected to the sockets wliicli are set into table top at any desired point. A detailed description of this apparatus with illustrations ^\^ll appear in the near future.

JfO. The growth of organs iti the albino rat as effected by gonadectomy. S. Hatai, The Wistar Institute of .\natomy.

1. Except in the remaining sex gland itself, the partial removal of the sex glands does not produce any significant alterations in any of the ductless glands aside from a general tendency to a slight increase. Apjxirently this increase in the remaining gland is sufficient to compensate for the functions of the lost gland.

2. The total removal of sex glands, however, induces alterations in all the other glands, ])articularly in the thymus and hypophysis. The sujirarenal glands show opposite reactions in the two sexes. In the case of the males, the suprarenal glands show an increase of 15 per cent, while in the female there is a 20 per cent reduction.

3. The total removal of the sex glands tends to increase the resemblance between the two sexes, or in other words, to reduce the chfTerences in those secondary characters which, in the normal animal, are modified according to sex.

41. Ganglion cells of the terminalis nerve in the dogfish. Paul S. McKiBBEN, The Western Universitj^. Ontario, Canada.

J!^2. The fate of the ultimo branchial body in the thyroid. B. F. Kingsbury, Cornell University.

43. The position of the normal stomach, mth observations on the movements

of the diaphragm. Burton D. Myers, Indiana Universit}' School of

Medicine.

Fort}' young adults, nineteen to twenty-six years of age, twenty-eight men and twelve young women, were given a buttermilk-barium sulphate meal. Their stomachs were then examined fluoroscopically.

Prior to giving the meal, copper washers were fixed with adhesive tape to the abdominal wall in the mesial sagittal plane, one on the processus x\'phoideus, a second at the transpyloric plane, a third on the umljilicus, and in the young women, a fourth was placed at the intersection of the intertubercular plane and the linea alba. These washers, plainly visible on the fluoroscopic screen, give the chief horizontal i:)lanes and the midsagittal ])lane. An adjustable diaphragm made it possible to cut the rays to a vertical slit, to a horizontal slit, or to a very small square opening, in which latter case, the rays are nearly parallel.

Inasmuch as in the young women, only a thin kimona intervened between the washers and the thirteen inch-s(iuare fluoroscopic screen, while in the case of the men, tlu; screen was jilaced innnediately upon the wa.shers and alxlominal wall, the error due to divergent rays is negligible, and checked \)\ narrowing the diapiiragm.

Sheets of very tiiin tracing paper were piacc^d upon the fluoroscopic screen and tracings made of the stomach while hlling, when full, in deep

PROCEEDINGS 129

est inspiration and fullest expiration accompanied by contraction of abdominal walls. Tracings were also made of the diaphragm, showing its normal position, its swing in normal respiration, and its extreme positions in forced inspiration and expiration. These same tracings were repeated with the individual in horizontal position (on back). X-ray photographs were made of five cases, for comparison and check.

In males, when standing, the average position of the lower border of the stomach was found to be one inch below the umbilicus, the extremes being from one inch above to three inches below this plane. In females, when standing, the lower border of the stomach was found to be three inches below the umVjilical plane, the extremes being one and threeeighths to four and one-half inches below the umbilical plane. When standing, the stomach is either J- or cow-horn shaped. The pyloric valve points upward, backward, and to the right. When lying down, the pyloric valve is one-third of an inch below the transpyloric plane, and in 12§ per cent of cases, it points upward, backward, and to the left; the descending portion of the duodenum then lies posterior to the pyloric portion of the stomach.

The cardiac stomach is not a storehouse for food, as commonly stated, but when standing, a gas pocket. The stomach fills from above downward, the upper border of its contents remaining, during filling, at the level of the esophageal opening.

The stomach is always as big as its contents. Its shape depends upon the quantitj' of its contents, the position of the body, the distention of adjacent viscera, peristalsis, and respiration. In certain cases even the beat of the heart gives a blow to the stomach wall which cau.ses a wave to run across the surface of its contents.

The stomach is normally in a state of tonic contraction so that when one lies down, the portion of the stomach over the vertebral column tends to empty and contract while the fundic portion accommodates an increased portion of the stomach contents.

In the erect position, the fundic portion of the stomach looks upward, not backward as stated by His and Cunningham. The surfaces are not up and down, but anterior and posterior, or antero-superior and posteroinferior as we stand or lie down. The greater curvature is not higher but lower than the lesser. The lesser curvature does not Ijecome convex when the stomach is filled, filling l)eing accommodated by distention of th(^ greater curvature. The position of the incisura angularis, with reference to the pyloric valve, varies with the high or low position of the pyloric valve.

Tiic normal position of the dia]>hragm is higher when one is in the horizontal, than when in the erect jwsition. Xot infrequently, Ci^ntraction of the abdominal wall is accompanied by descent of the dia])hra^i. Though some females employ costal respiration almost entirely, as do some men, others show as great a swing of the diajihragm in normal respiration and as great extremes of movement of diai^hragm in forced insj)iration and expiration :i:s is found in men.

THE ANATOMICAL BECORD, VOL. 8, NO. 2

130 AMERICAN ASSOCIATION OF ANATOMISTS

44- The form of the stomach in mammalian embryos. Chester H.

Heuser, The Wistar Institute of Anatomy.

In The American Journal of Anatomy ('12, vol. 13, pp. 477-503), F. T. Lewis described the form of the stomach in young human embryos and the development of its primary subdivisions. During the past year, with the aid of Bullard Fellowships awarded at the Harvard Medical School, the writer has made a similar study of the embryonic stomachs of the albino rat, pig and sheep, and the work is approaching completion. In all of these animals as in man, the epithelial stomach is a ea rl^' - subdivided into cardiac and pyloric portions, separated by the angular incisure. The pyloric portion is often onl}^ obscurely subdivided into an antrum and vestibule, but the cardiac portion clearly presents a corpus and fundus. The early development of the gastric canal is a notable feature in all the animals studied, as could be seen in the series of wax reconstructions which were presented as a demonstration.

45. On the -phylogenesis of the heart. A. G. Pohlman, St. Louis University.

The first sign of a division in the heart occurs in the lung-fish with the appearance of an incomplete auricular septum. The next step is found in the amphibian with an incomplete division of the bulbus by the spiral valve (see below) in addition to the incomplete auricular septum. The third stage is found in the reptile with the complete separation into two auricles and the completed division of the bulbus and the appearance of an interventricular septum. The fourth stage comes in the crocodile family with complete division of the heart into four chambers, the right side having greater capacity than the left. The fifth in the bird and mammal with a four-chambered heart and equal capacity on the two sides. Just as the foramen ovale appears as a functional compensation for the inequality of return to the two sides of the heart in the fetal bird and mammal, so the foramen of Panizza may be a functional adaptation to the unequal quantities of blood expelled by the two ventricles. This latter point is not thoroughly understood. There is no proof of a segregation of arterial and venous blood throughout the vertebrate scale excepting in the postfetal bird and mammal and possibly in the crocodile family.

Demonstration of reconstruction of the bulbus cordis in the frog. This reconstruction shows: (1) that the spiral valve cannot function in the manner described as a means of separating the bulbus into an aortic and pulmo-cutaneous compartment; (2) that the carotid arteries arise by a common opening; (3) that this opening is again in common with that of the right aortic arch ; (4) that the left aortic arch has an entirely independent opening about at the level of the pulmo-cutaneous opening and is distinct from the right aorta. Both left aortic and pulmocutaneous openings have a valve which is wanting in the right aortic opening; (5) that the spiral valve may be interpreted as an incomplete division of the bulbus analogous to the incomplete division of the auricle

t/^/y

fiD'

ERRATUM

The Anatomical Record, volume 8, number 2, February, 1914, Abtract 44, Chester H. Heuser, page 130, line 9, for nearly read early.

. PROCEEDINGS 131

and the relations of the left aortic arch and pulmo-cutaneous artery are suggestive of a phylogenetic step completed in the turtle.

1. Demonstration of the canalis cranio-phar>'ngeus in the rabbit showing the possibilities in experimental work in this form of determining the relation of naso-pharyngeal irritations upon the hypophysis and upon the pharyngeal hypophysis and its bearing on the adenoid question. Preparation of Dr. Eugene Senseney.

2. Demonstration of elastic ligaments in the middle ear region of the chicken which may afford resistence to the pull of the tensor tympani. Preparation by INIr. Wilson and Mr. Shores.

3. Trilocular heart with pulmonary stenosis in a child of ten 3'ears (case of Dr. Ralph Thompson) to show transposition of vessels and an absolute lack in separation of arterial from venous circulation.

j^. Some notes on early twin human embryos. James Crawford Watt,

Anatomical Laboratory of the University of Toronto.

These twin embryos are Xos. V and VI in Prof. J. Playfair McMurrich's collection. They are respectively 2.75 mm. and 3.35 ram. in length. They are almost identical in development, but one has a very deep concave dorsal bend, while the other is almost flat. Embr\'o V has 17 to 18 paired somites, Embryo VI has 18 to 19. They thus serve to fill in an interval hitherto lacking in good specimens.

In the alimentary system the buccopharj'ngeal membrane is just rupturing, the pharj-nx has three gill-pouches and a medium thyroid depression. Connection with the \o\k sac is very extensive. The cloaca is small but is divided into rectal and bladder bays.

The notochord is still attached to the gut throughout much of its extent. In places it shows the remains of a notochordal canal and a chord of cells extending from the medullary plate to the notochord in both embryos and also from the notochord to the cloaca in Embn,-o V, represents the neurenteric canal. These are the oldest embn.'os recorded which exhibit these remains.

The urinogenital system of Embryo VI consists of five pronephric tubules on each side, united to the Wolffian duct. Behind are ten to eleven mesonephric vesicles on each side, not united to the duct, which extends from the ninth to the sixteenth mesodermic segments. In Embryo ^' the duct on the left extends from the nintii to the sixteenth segment and receives seven pronephric tubules, and on the right it extends from the seventh to the sixteenth segment and receives eleven tubules. There are five to seven mesonephric vesicles behind these. Many of the tubules exhibit nephrostomes and there is an external glomerulus in the ninth segment of Embr>'o \T. There is evidence of dysmetamerism, as many tubules occur in pairs in the segments on each side.

The heart is a simjile S-shaped tube. Only the large embryological vascular trunks are develojied, including two branchial arch vessels on each side. The brain sliows three primary vesicles, optic vesicles, hypophysis, and seven ncuromeres in the hind brain \\\X\\ four ganglia — tri

132 AMERICAN ASSOCIATION OF .\NATOMISTS

geminal, aciisticofacial, glossopharviigcal and vagus — attached to definite neuromeres. A complete and full description of the embrj^os will be published shortly.

Jf7. Notes on the skull of a kuvian fetus of 50 mm. C. C. Macklin, Anatomical Laboratory of the University of Toronto. The skull described occu]:)ies a position intermecUate between the 28mm. stage of Levi and the 80-mm. stage of Hertwig, and is interesting in that it shows indications of a reduction of the lateral walls of the chondrocranium in the form of small isolated remnants of cartilage situated dorsally and lateralh'. Other similar isolated cartilages also occur, among wl ich may be mentioned a rudiment of the aUcochlear commissure; an ephemeral representative of a primitive nasal concha, seen in the middle meatus of the nasal cavity; and a small mass in the orbit, lying against the nasal capsule. A minute additional paraseptal cartilage is noted, attached to the nasal septum, and related to the vomerine anlage, while the anterior paraseptal cartilage presents an interesting transitional stage in which it may be directly compared ^^^th that of such form as the rabbit, and the paraethmoidal cartilage, related to the lacrimal bone and duct, is also well developed.

The condition of the structures surrounding tl e foramen magnum throws some light on the development of this region, especially in regard to the part played by the occipital vertebra, which is, in this stage, rather distinctly outlined. A detailed description of the skull, with figures showing its reconstruction, ^\•ill shorth' be published.

48. The development of the pancreas in selachians. Richard E. Scammon,

Institute of Anatomj^ L^niversity of Minnesota.

The pancreas of selachians is remarkable in that it arises from a single diverticulum which has generally been described as dorsal in position. It is, however, very difficult to determine the exact position of this anlage by the customary means of reconstruction. For this purpose, therefore, I have applied the method of gra])hic reconstruction devised by Weber. This method, which seems to me a most valuable device for studying the early stages of the larger glands, has apparently been employed only by its originator some ten years ago in an extensive study of the earliest stages of developme^nt of the liver and pancreas in Amniotes. The details of this procedure can hardly be given in the space allotted here. The}^ may be found in Weber's original work (Arch. D'Anat. microsc, T. 5, '03), and will be again presented in this paper in its final form. In general terms, it is a modification of the graphic method of reconstruction in which the varying thickness of the e])ithelium of the reconstructed archenteron is represented in corresponding varying shades of color so that one may stutly the various areas of epithelial thickening in much the same way that one interprets the elevations of land in a topographic map.

A reconstruction made in this mamier of the midgut of an Acanthias embryo 5.2 mm. in length, which is of a stage well preceding any indica

PROCEEDINGS 133

tion of the pancreas as an outpouching, shows in the future pancreatic region of thickened epithehum which includes not only the dorsal zone of the gut but extends well ventrally. This pancreatic area is connected with a large thickening ventral and anterior to it which constitutes the liver anlage. These two thickenings, the pancreatic and hepatic, constitute, with the thickened epithelium connecting them, a ring which passes obliquely completely around the archenteron. The existence of such a pancreatic-hepatic ring was pc^stulated long ago by Brachet and has been demonstrated to a great extent in .\mniotes Vjy Weber.

Reconstructions by Weber's method of the midgut regions of embn,'os of Acanthias 7.5, 9 and 10 mm. in length, show a gradual breaking up of this ventral hepatic segment. Between the two the epithelium remains somewhat thickened and in this occurs a particularl}' thickened patch which occupied the same position as does the anlage of the ventral pancreas in the higher vertebrates. This thickened plate never produces an outpouching and disappears in older embryos. While the dorsal outpouching of the pancreas is a single one, there is in Acanthias at least, an early indication of chvision into right and left lobes. This di\'ision is not very distinct and can hardly be demonstrated \\ithout Weberian and plastic reconstructions. In Acanthias the left lobe lies anterior to the right and is the smaller. It forms in embryos from 15 to 35 mm. in length a distinct antero-ventral mass which later is to a considerable extent incorporated in the descending limb of the gland. In such other selachians as I have studied this lobe lies posterior to the right one. This is probably because the left lobe is not differentiated until the gland begins to separate from the gut and in all selachians except Acanthias separation takes place antero-posteriorly. I do not think that the bilobed dorsal pancreas is to be regarded as a primitive condition. Rather it is produced b^- the clock^\•ise rotation of the gut and the formation of the spiral valve. Bilobed dorsal pancreas anlagen are fomid in mammals and in selachians but have not been clearly demonstrated elsewhere unless one accepts the observ^ations of von Kiippfer the value of which has been rendered doubtful by the work of Piper antl Nicolas. It seems then that the bilobed form of dorsal pancreas is limited to those forms in which the clock\Nise rotation of the gut (common to some extent to all vertebrates) takes place at an early period and that this form of pancreas is due to that rotation.

A more complete statement of the development of the selachian pancreas will be published in the near future.

49. The development of the gall bladder and bile duds in amblystoma.

E. A. Baumg.\rtner, Institute of Anatomy, University of Mume.^ota.

Models of embryos 4.5 mm. long show that the liver anlage is a ventral, somewhat caudal i)rojection of the gut lumen caudal to the heart. That this does not corresjwnd to tiio caudal hci)atic duct describotl in chick is shown by later stages. In models of embryos ai>out 7 mm. long we see this early ventral outpouching has turned cranialward. In the ventral wall where the primitive common duct joins the gut lumen a me

134 AMERICAN ASSOCIATION OF ANATOMISTS

dian depression shows the earUest anlage of the gall bladder. In stages of about 9 mm. length the folds have become numerous and are the anlage of radicles of the main hepatic ducts. That they are not entirely formed by the tumieling in of blood vessels as has been described by Shore, is shoA\'n by the fact that furrows are found in which no blood vessels are present. The earl}- anterior, and laterally extending duct shows begimiing constriction and elongation into right and left hepatic ducts. A little later the gall bladder has shifted to the right and is no longer widest transversely. The cystic cfuct also has shifted to the right, now being attached to the ventral side of the right hepatic duct. The shifting of the gall bladder is accompanied by a shifting of the entire caudal part of the liver due to the sinistral and ventral growth of the stomach and duodenum.

From graphic reconstructions of late embryos we see an arrangement of the biliary apparatus as shown in the following outline:

Common duct

left hepatic duct right hepatic duct

It. lat. ramus . It. med. ramus rt. med. ramus rt. lat. ramus

branches — lat., med. lat., med. med., lat. med., lat.

cystic duct

Occasionally the left medial and right medial rami join to form one duct which subdivides as a single stem. This is a secondary union and per.sists in the adult. Also in some cases the cystic duct was found to be one subdivision further removed, that is, it was attached to a radicle of the lateral branch of the right hepatic ramus.

In embryos between 10 and 12 mm. in length, division and growth of the early duct into right and left hepatic ducts and of these into rami takes place. A graphic reconstruction of a 13 mm. stage shows that this has taken place. The gall bladder here is now longest postero-anteriorly and the short cystic duct extends upward and to the left. A model of a 14 mm. embryo shows that the gall bladder has shifted more to the right and that its duct which is attached to the extreme anterior end extends somewhat upward and to the left.

A model of the biliary apparatus of a slightly older embryo shows greater development of the duct system. The gall bladder is longer anteroposteriorly, its duct is attached more caudally and is almost horizontal. In a 15 mm. embryo there is a short common duct, but the right and left hepatic ducts are longer. The right lateral shifting here is more marked. The cystic duct extends horizontally to the left. This stage marks the extreme caudal attachment of the cystic duct to the gall bladder.

PROCEEDINGS 135

At the 20 mm. stage the lateralward shiftmg is very marked. The right hepatic duct is now somewhat dorsal to the left. Here the right and left medial rami have imited to form one duct. The gall bladder has increased very materially in size, particularly in its caudo-cranial diameter. The cystic duct has shifted toward the anterior end and now projects to the left and dowTiward. The extreme of the lateralward shifting has been reached in a 35 mm. embryo. The right hepatic duct here is quite dorsal in position in relation to the left. Its lateral radicles are also more dorsal than its mecUal. The left lateral ramus has turned caudalward to sujjply hepatic radicles to the further caudal extending left lobe of the liver. The gall bladder has increased in its dorso-ventral diameter. Its duct is attached at the anterior end and extends toward the left and doT\Tiward as before. In a 45 mm. embryo and larger ones the right and left hepatic ducts are again more nearly in a horizontal plane. The cystic duct is attached to the anterior medial end of the gall bladder,

Summary. (1) The ductus choledochus develops as the early anterior directed duct from the gut. (2) The right and left hepatic ducts develop as divisions of the ductus choledochus and by groT\^h and division form the hepatic rami and branches. (3) The gall bladder begins as a median ventral outpouching of the early anterior forming liver anlage. It is first widest laterally and finally obliquely caudo-cranially. (4) There is an early right lateral shifting of the biliarj' apparatus. Along with this there is a constant shifting direction of the cystic duct in keeping with the dorsalward migration of the gall bladder. (5) The cystic duct is early closed off with the right hepatic and finally is attached to the lateral branch of the right lateral ramus.

50. Heteroplastic development of eosinophil leucocytes and of hematogenous

mast cells in bone marrow of guinea-pig. IL\l Downey, University of

Minnesota.

According to Weidenreich and many others the granules of eosinophil leucocj'tes are composed of exogenous substance derived from hemoglobin or its dissociation products. Weidenreich's conclusions are based on a study of local development of eosinophils in heniol>'mph nodes, and in the taches laiteuses of the omentum of rabbit follo^\^ng the injection of guinea pig erj-throcj-tes into the body cavity. Weidenreich's conclusions are based on vers- good evidence, as the writer can testify from personal study of his material. However, for the bone marrow the e^^dei|ce for Weidenreich's view of the origin of the eosinoiihils is not so conclusive. The main facts in its favor are the observations of Marwedel and others that there is considerable degeneration of erythrocytes in the bone marrow, especially during inflammation, when the process is accompanied by the formation of numerous pigment cells and the occurrence of numerous eosinophil myelocytes which contain pigment granules.

The other view in regard to the origin of eosinophil leucoc>'t^s, especially in the bone marrow, is, that the granules of these cells are true

136 AMERICAN ASSOCIATION OF ANATOMISTS

endogenous plasma differentiations of the non-granular cells concerned, and that the cells antl their granul(>s undergo a definite evolution during their differentiation which is accompanied by changes in the staining reaction of the granules. The granules are basophilic when they are first formed, but they gradually ripen into acidophilic granules. Such a process has been descril^ed in more or less detail by Ehrlich, Hirschfeld, Pappenheim, Maximow and others. Weidenreich admits the presence of basophilic granules in eosinophil myelocytes, but states that they are either endogenous granules which have nothing whatever to do with the eosinophil granules, or that they are fragments of the nucleus Avhich are of the same size as the granules and therefore difficult to distinguish from them. He believes that the eosmophil granules are the expression of the taking-in of substances and particles which are formed by a special kind of erythroc>i:e degeneration either without or within the cell. He states that no other form of the development of the granulation has ever been observed, especially not a gradual differentiation from a non-granular protoplasmic cell-bod}', as is knouii for the special myelocji^es.

Our i)roblem is to determine whether these statements of Weidenreich are really true for the bone marrow, or whether the view stated above is the correct one. Without figures a detailed description of these investigations is impossible, however, the results can be stated in a few words and the demonstration of the slides'will make the drift of the investigation clear.

The preparations show clearly that the granules of the eosinophil myeloc}i,es are gradually differentiated out of a non-granular protoplasm, and that the first granules are basophilic. Tl e preparations also show clearly that these basophilic granules are. transformed directly into the eosmophilic granules. Both of these statements are denied by Weidenreich.

The first granules are small and not numerous, and it is very often difficult or impossible to distinguish them from the myelocytes of the special cells, a point which has already been emphasized by Maxunow, who believes that in embryo rabbits and guinea pigs there is a common granular parent-form for both eosinophils and special cells. Fortunately it frecjuently hai)pens that some of the granules enlarge far beyond the size of the special granules while there are still only a fcAV of them in the cell. This fact enables us to detect some of the very early stages in the differentiation of the eosinophils and to distinguish them from the special cells. The granules remain unequal in size during the differentiation of the cells, the youngest granules being small and basophilic, while the older ones are larger and (H)sinophilic. Some of the granules change their staining reactions while they are still small, while others remain basophilic until tliey have reached a size even greater than that of the fully differentiated granule before such change takes place. That these larger granules do not disappear, and that they are transformed directly uito the eosinophil granules is showai l\v the fact that many of the largest ones are stained in the acid component of the staining mixture, while others are of a mixed tone. These developing granules are round, and

PROCEEDINGS 137

variable in their staining reaction and in their size, but later the}' are of about equal size, which is less than that of the largest developing granules, and they become elongated and uniformly acidophihc. In other words, the granules of the eosinophil leucocj'tes during heteroplastic development are gradually differentiated out of a non-granular protoplasm, and thej' pass through a gradual progressive evolution which is the equivalent of that of the special granules, and which indicates that they are endogenous formations. If hemoglobin or its products has anj-thing to do with their formation it is not e\'ident from a study of the normal bone marrow Anth the ordinary histological methods.

The fact that the yomig granules of both eosinophil and special mN'eloc\i:es of rabbit and guinea pig are basophilic has lead Pappenheim and his students Benacchio, Kardos and Szecsi to the conclusion that there are no true mast leucoc\i:es in the blood of these animals, at least that no such cells are formed in the bone marrow. They concluded that the mast cells are merely unripe eosinophils and special cells. An investigation of this question had been completed and the figures dra\\Ti when Maximow's paper dealing with the same subject appeared in the last number of the Arch. f. mikr. Anat., consequently there is little left for the A\Titer besides confirmation of Maximo w's results. In so far as the guinea-pig is concerned, there is no difficulty whatever in recognizing the mast granules the moment they appear. The mast leucocytes of this animal are so definite and characteristic that they can be identified from the moment of their first appearafice in the bone marrow. The slides which have been demonstrated give sufficient proof of this fact, so it is unnecessary to give further detail, excepting the general statement that the staining reactions of the mast granules and their general shape and size are very different from those of the young eosinophil or special granules. Therefore, for the guinea-pig, the results obtained by Pappenheim and his students from their investigation of this question are here\Wth most emphaticalh' rejected.

The results of the present investigation show further, that heteroplastic development of various types of granulocNiies from non-granular cells is a very active process in the marrow of adult gumea-pig. According to Helly the only normal process of leucocyte regeneration in adult human bone marrow is a homoplastic form of development by mitosis of the corresponding granular myeloc^-tes. All non-granular cells of the marrow are, according to this author, either erythrogonia which are associated with anemic degeneration, or pathologically "entdiflferentidted" myeloc^-tes.

Many mitotic figures are seen in the various tyjx's of myelocytes of the guinea-pig marrow, which shows that active mitosis continues for some time after the cells have differentiated gnmules; iiut besides this homoplastic form of development, which is the only one recognized by Helly, there is also very active heteroplastic regeneration from nongranular cells.

51. Some vnrintions of (he thoracic duct. Henry K. Davis, Department of Anatomy, Cornell University, Ithaca.

138 american association of anatomists

Tuesday, December 30, 2.00 p.m. to 5.30 p.m. the following demonstrations were presented :

1. The Frankfurt method of mounting microscopic sections in photographic

gelatine, without cover-glasses. William H. F. Addison, University

of Pennsylvania.

Specimens of thin sections of human cerebrum were shown covered with photographic gelatine instead of Canada balsam and glass. For more than twenty years Professor Edinger of the Neurological Institute in Frankfurt has been trying such things as varnish, celluloid, celluloid films and kodak films as an inexpensive and convenient substitute for the usual mounting and covering substances, and at last suggested to Dr. R. E. Liesegang, the well-known photographic chemist who was working in the laboratorj^, the use of gelatine. The method has been in use for several years, and is especially convenient with large sections of the brain stained by the Weigert method. It may, however, also be used on celloidin, paraffin or frozen sections, and mth any stain except aniline dyes in aqueous solution. The photographic gelatine is soaked in water mitil soft (1 part of gelatine in 10 parts of water for about an hour) and dissolved by gentle heat, by immersing the wide-mouthed bottle containing the softened gelatine in heated water (not over 50°C) . The gelatine solution is filtered through filter paper at 39°C. in an oven, before using. The sections must come into water before they are ready to mount. After draining off \he. superfluous water from the preparations on the slide, the gelatine solution is poured over the slide, and the slide placed in a dust-free atmosphere to dry. A gentle current of air aids in the hardening process. The result in several hours to overnight is a very thin hard covering of gelatine, which appears perfectly transparent. It is best to prepare the gelatine solution in small quantity, for example, 50 or 100 cc. and to make it fresh each time before using.

The method was first published by Liesegang in 1910 (Zeitschrift fiir Wissensch. Mikr. Technic, Bd. 27) and further developments of it have been described recently by Professor Edinger (Neurologisches Centralblatt, Juli, 1913) where a description is given of further special details. Thus in dealing with thick sections it is well to soak them in the 10 per cent gelatine solution in the oven at 39°C. for an hour before mounting, to insure penetration of the gelatine. This is not needed with small ordinary sections. The hardening process after mounting may be assisted by dipping the slides in 10 per cent formalin about an hour after pouring on the gelatine.

Another special use is to cover preparations which have been stained for fat by Sudan III, or Scharlach R. where a dehydration with alcohols must be avoided. The sections are mounted with gelatine immediately from water with no other after-treatment. Specimens of heart muscle mounted in this way retain the stain unimpaired.

The method is still being perfected but already it has proved inexpensive and convenient for large brain sections and useful in the preservation of sections stained for fat, as well as for other more ordinary preparations.

PROCEEDINGS 139

2. Preparations to show the formation of red blood-cells in the developing thymus of the pig. J. A. Badertscher, Cornell University.

3. Demonstration of preparations showing the behavior of endothelium after the introduction of emboli in the portal vein. Roger P. BatchELOR, Johns Hopkins University.

The experiments of Evans and co-workers have conclusively demonstrated the endothelial origin of giant cells in liver after infection with a suspension of tubercle bacilli. The endothelial nature of the cells concerned was established by means of vital stains. The study here demonstrated was suggested by Dr. Evans and undertaken to test whether this phenomenon was peculiar to the tubercle bacillus or any micro-organisms and secondly to study the reaction of the endothehum of relatively large branches of the portal tree. A preliminary injection of trjq^an blue was made and a week later, the colic vein exposed and five cubic centimeters of an aqueous suspension of baked egg albumen injected toward the liver.

The albumen flakes which were very minute and easy to cut in serial sections of the tissue subsequently, were made by beating the albumen to a fine foam and baking the same at high temperature.

On the evening of the same day and on the third and fifth da}' s after operation, the animal was given each time an intravenous injection of from 14 to 20 cc. of fresh 1 per cent, aqueous trypan blue.

The animal was killed later in the afternoon of the fifth day and the tissue preserved in formol. Frozen and parrafin sections showed: (1) Endothelial giant cells lying in the intralobular hepatic capillaries. These were sometimes multinucleated and contained phagoc\i:ized albumen flakes. In all cases they stained intensely with the vital stain, and this fact, together with their occasional structural continuity with the neighboring capillary endothelium, demonstrated their endothelial nature; (2) The endothelial lining of those branches of the portal tree which were plugged with emboli showed marked proliferative changes.

This newly formed endothelial tissue existed at the site of the embolus and in its immediate neighborhood and partially occlude the lumen of the vein. It is stained vitally, a phenomenon never seen with the normal endothelial cells of large vessels, and showing that the ^^tal stain is adequate for the detection of endotheUal growtlis although the parent tissue does not show this property.

It is possible in this way to distinguish the role of endothelium in contrast to that of the mono-nuclear blood cells certainly in all intravascular lesions.

4-. Demonstration of fat in the muscle fibers of the myocardium and of the

atrio-ventricular system. H. ILws Bull.\rd.

Th(^ normal fat content of cardiac fibers and of muscle fiberl of the atrio-ventricular system was shown by tissue sections which had been treated with fat stams. A stained preparation of the true interstitial granules of myocardial fibers was also shown.

140 AMERICAN ASSOCIATION OF ANATOm!sTS

5. Specimen illustrating the development of the pancreatic duct-system in the pig. George W. Corner, Johns Hopkins Medical School.

6. Pyridine silver preparations of the vagus nerve of man, dog and cat. j\I. R. Chase, Northwestern University Medical School, Chicago.

7. Microscopic preparations showing ?norphological and staining characteristics of the nuclei of lymphatic arid blood vascular endothelium and of the mesenchyme cells in chick embryos. Eliot R. Clark, Johns Hopkins ^Medical School.

8. Microscopic slides illustrating experimental studies of mesothelium. William Cogswell Clarke, Columbia University.

9. The staining of mitochondria in human lymphocytes with janus green. E. V. CowDRY, Johns Hopkins Medical School.

Mitochondria were stained, intravitam, in the l^Tnphocytes of freshly draAm human blood with a solution of 1 : 10,000 janus green (diethyl safranm-azodi-methyl-anilin) in physiological salt solution.

Mitochondria were also demonstrated in the h'mphoc}i:es of blood cells in smears fbced m 2 per cent, osmic acid and Bensley's acetic osmic l)ichromate mixture, and stained by the regulation Altmann method and b}' Bensley's anilm fuchsin methyl green method.

The mitochondria seen with the aid of the vital dye and those in the fixed and stained preparations showed a striking similarit}^ with respect to their relative number, shape and cytoplasmic distribution.

10. Preparations illustrating vital staining with various benzidine dyes. Herbert M. Evans, Johns Hopkins University.

11. The melanophores of tadpoles. Davenport Hooker, Yale University.

The melanophores of both larval and adult frogs were demonstrated in fixed preparations to show their component parts, structure and relation to the spaces which contain them. The larval melanophores showed the even distribution of the pigment in the expanded phase and the absence of processes in the contracted phase. The adult melanophores showed the nature of the processes and their al^sence in complete contraction of the cell. In both the larvar and adult, the spaces Avithin which the cells lie were demonstrable and their relation to the cells, especially in the adult, clearly to be seen.

12. Teased preparations showing complete seminiferous tubules of Mammalia. G. Carl Huber, University of ]Michigan, Ann Arbor, ]\Iich.

13. Microscopic slides and charts illustrating the genetic relations of lymphatics and hemal vascidar channels in the embryos of amniotes. George S. Huntington, Columbia University.

PROCEEDINGS 141

14- A demonstration of certain embryonic vessels of amhlystoma, nedurus and frog. Henry ]\IcE. Knower, University of Cincinnati.

15. A syringe for injecting tissues, giving a continuous flow at any desired pressure. Frederic P. Lord, Dartmouth Medical School, Hanover, New Hampshire.

16. Microscopic slides illustrating experiments on the development of the blood vessels in the blastoderm of the chick. A. ^I. Miller axd Johx McWhorter, Columbia University.

17. Pyridine silver preparations of the spinal cord of the cat and Rhesus monkey. S. Walter Ransox, Northwestern University ^ledical School, Chicago.

18. Preparations shoiving the vital stain applied to the study of woundhealing. KA.THARIXE J. Scott, Johns Hopkins University.

It has been found that the injection of benzidine dyes results in the deposit of granules in the cells of connective tissue, and that these cells carrying granules are of two types, corresponding in turn to true fibroblasts or fixed cells and to the cells spoken of as resting wandering cells" or clasmatoc\i:es. In view of this obser\'ation, it has seemed important to study the process of wound-healing in animals receiving large amounts of the dye, and to study especialh* that stage of the process during which new connective tissue is formed, in the hope of throwing new light on the ciuestions of the function and specificity of these cells under given pathological conditions. For this purpose knife wounds have been made in the skin, liver and kidney of rabbits stained with trypan blue. As demonstrated, wounds in the hver of 6 to 7 days duration show extensive necrosis of liver parench^Tna in the region immediate to the line of incision. The dead liver cells, nucleus and c\-toplasm, stain a diffuse blue, except in the center of the necrotic area, where the dye does not penetrate. The microscopic pictures resembles that of a small abscess, the un.stained portion showing strong contrast to the blue-black organ. ^licroscopically, the dead tissue is surrounded by masses of granule-laden phagoc^-tic cells which appear to have arisen in situ from pre-existing endothelial cells, or Kupffer cells, a reaction apparently homologous to that observed in tuberculous livers.' These phagoc>-tic cells appear very like the macrophages of the peritoneal cavity. New tissue, arising in adhesions of the mesentery near the woimd. shows fibroblasts of embryonic character, with tyjiical fine, blue granules, as well as the cells of polyl^lastic character with coarse granules. A womid of the same duration, m the kidney, gives a very ilifferent picture. The line of incision is filled with new connective tissue, the cells of which are

• Evans, Bowman, Winternitz : An experimental study of the histogenesis of the miliary tubercle in vitally stained rabbits. Jour. Exp. Med.. 1914.

142 AMERICAN ASSOCL^TION OF ANATOMISTS

strikingh' free from dye granules, in spite of the abundance of dye-containing cells in the surrounding kidne\' tissue and capsule. Necrotic cells of injured tubules are present N\-ithout any of the striking phagoc>i;es seen in the liver wounds.

19. Microscojnc slides illustrating early stages of vasciilo-genesis in the cat (Felis domestica). H. von W. Schtlte, Columbia University.

20. Preparations and drawings showing the results of a modified Weigert technique applicable to serial paraffin sections of the adult human brain. Ralph Edward Sheldon, Department of Anatomy, School of ^ledicine, University' of Pittsburgh. (Full description of methods to be published in FoUa Neuro-Biologica, vol. 8).

21. G. L. Streeter, University of Michigan.

a. SLx sections showing labyrinths in tadpoles that had been transplanted in each case from other specimens at an early stage. In spite of the fact that in the transplantation thej^ were placed intentionally in an inverted position, they developed, as sho\\-n by the sections, in the normal manner and in the normal posture. That is to say, thej' corrected their displacement.

b. A blue print catalogue of about 300 lantern sUdes. The blue print sheets, sho^^dng mostly six slides to the sheet, are mounted in a loose leaf note-book holder.

c. A dry-preparation of the laryngeal cartilages, together ^vith the hyoid bone and the upper four tracheal rings. This mount was prepared in the manner described in the paper given in the general program under the title "Technical experiences".

22. Microscopic slides illustrating a case of hemicerebellar atrophy. O. S. Strong, Columbia University.

23. Micro.^copic slides and reconstructions illustrating the morphology and developmetit of the diencephalon in mammals. Frederic Tilney, Columbia University.

24. Specimens bearing on the nature of fat cells. H. G. Weiskotten and H. S. Steensland, SjTacuse University.

25. Microscopic slides illustrating the development of the caudal lymph hearts in the chick. Randolph West, Princeton and Columbia Universities.

26. Specimens showing vital staining of the interstitial cells of the testis. R. H. Whitehead, University of Virginia.

27. Models illustrating the development of the gall bladder and bile ducts in ambbjstoma. E. A. Baumgartner, Department of Anatomy, University of Minnesota.

PROCEEDEXGS 143

28. Reconstructions illustrating the development of the suprapericardial

body in Squalus acanthias. W. E. Camp, Institute of Anatomy,

University of ^Minnesota; (presented by R. E. Scammon).

The bodies in question were discovered by Leydig in 1853 in Anuria, and were described as accessory th}Toids. Van Bemmelen (Mitt. Zooi. Stat. Xeapel, Bd. 16, '86 j first described these structures in ela.smobranchs as 'suprapericardial bodies.' He considered them to represent rudimentary seventh pouches.

The models were made in two series: Series A, to show the position of the bodies, and their relation to the pharv-nx and its derivatives; Series B, at a much higher magnification to show the form and later development of the bodies.

Series A, ]Model 1. Reconstruction of the phan.-nx of a 20.6 mm. embryo fH.E.C.1494).^ The suprapericardial body is present only on the left side where it is represented by a simple thickening of the epithelium of the ventral phar^Tix wall. It extends through four sections of 10 n and lies at the same level as connection of the sLxth pouch of the left side with the phar^-nx.

. Series A, ]\Iodel 2. Reconstruction of phar\Tix of 33.1 mm. embr\'o (S.C.8). The suprapericardial bodies are present on both sides. The body on the left side is ven*' much the larger. The right body in this embrs'o is represented b^' two slender villus-like projections of the epithelium extending doAvn into the mesench\Taa between the pharynx wall and the pericardium. They have no lumina and are found only in three sections of 12 n. The body on the left side consists of a single, fairly well developed cyst which is connected at right angles ^ith a stalk which has a lumen continuous with the C3'st and is connected ^^^th the pharj-ngeal epithelium. The bodies are in about the same relative position as in the preceding embr^'o. that is, a httle posterior to the be•ginning of the ventral diverticulae of the sLxth pouch and about halfway between this pouch and the median line.

Series A, Model 3. Recon.struction of the posterior part of the phar>Tix of a 47.3 mm. embryo fS.C.ll.) sho'W'ing the fourth, fifth, and sixth pouches. In this stage, due to the gro^^'th of the phar>-nx, the bodies have a more lateral position. As in the preceding embr^'o. the body on the left side is the more highh' developed. The form of the bodies at this stage is described in Series B.

Series A, Model 4. Reconstruction of posterior half of the phar>Tix of 95 mm. embryo if Squalus suckhi (H.E.C.1882). The position of the bodies at this stage is a little more median than in the one preceding. The bodies, particularly the one on the left side, are turned toward the midline from their origin from the phar^-nx wall. Arising just lateral to the posterior extremity of the body on either sitle of the phar>Tix and nmning do\Miward. outward and forward, is an elevated crest which ends on the right side in a fold of the esophagus and on the left side termi ' H.E.C = Howard Embrj'ological Collection; S.C = Embryological Collection of Dr. R. E. Scammon.

144 AMERICAN ASSOCIATION OF ANATOMISTS

nates just anterior the junction of th(^ flattened and exjianded pharynx with the eso])hagus.

Series B, Model 1. Reconstruction of the left supra]X'ricardial body of a 28 mm. embryo (H. E.G. 1357). The bod}^ consists of a single cyst connected ^^^th the pharynx wall by a hollow stalk. The cyst is directed anteriorly.

Series B, Model 2. Reconstruction of left .suprapericardial body of 37 mm. emliryo (H.E.C.363). The body is composed of a slender cyst, pointed at its anterior extremitj', and constricted at its middle. It is connected to the pharynx l)y a budding and contorted hollow stalk, which opens into the base of the cyst.

Series B, Model 3. Reconstruction of right supraperieardial body of, 47.3 mm. embryo (S.C.ll). This body is of about the same stage of development as the left body of the 28 mm. embryo.

Series B, Model 4. Reconstruction of left suprapericarcUal body of 47.3 mm. embryo (S.C.ll). The body at this stage consists clearly of tAvo parts. The first a single elongated cyst extending antero-posteriorly and widely comiected witli the ])harynx. This is undoubtedly the remnants of the early comiecting stalk. The second ])art, larger antl sepa-; rate from the first, consists of a branching and budding mass of tubules, the lumena of which appear to be continuous.

Series B, Model 5. Reconstruction of the left supraperieardial body of 95 mm. Squalus sucklii embryo (H. E.G. 1882). The body in tliis embryo consists of a complicated mass of branching tubules some of which anastomose. They are placed at an angle of about 45° to the ]3har>^lx wall. Remnants of the stalk are seen in three distinct solid cords connected Avith both the mass of tubules and Avith the pharynx Av^all. The greater part of the body extends anterior to its attachment to the pharATix. A feAA- small isolated cysts are present lying in close contact l)ut apparently not connected or fused Avith one another. The ventral . boundary of the body is sharply defined by a large elongated cyst Avhich is pointed at its anterior and bifurcated at its posterior extremity.

Summary. (1). The supraperieardial liodies develop from the A-entral pharynx Avail medial and at a])out the level of the sixth pouch. (2) The left supraperieardial body deA'elops progressiA^ely Avith the j^harAnix and its appendages. The right supraperieardial body is not present in all embryos and Avhen present is ahvays smaller and more rudimentary than the left one. (3) In the later stages the bodies consist of liranching tubules some of Avhich anastomose, and of a few isolated cysts. (4) The later groAvth of the bodies is directed anteriorly and is independent of the pharA'nx. (5) None of the bodies in the embrj'os examined shoAv anj'- fusion AA^th the thyroid.

29. Eosinophile leucocytes and hematogenous mast cells in the bone marrow

of the (juinea-pig. Hal Doavney, University of Mimiesota.

The demonstrations consisted of slides and draAvings Avhich illustrate

the heteroplastic development of the various tyj^es of granular leucocytes

in the bone marrow of the guinea-pig from non-granular cells. Besides

PROCEEDINGS 145

this the slides show that there are many polymorplionuclear mast cells and the corresponding myelocytes in the marrow of guinea-pig, which is contrary to the findings of Benacchio and Kardos, who state that there are no mast leucocytes in this marrow and no intermediate stages between mononuclear cells with coarse basophilic granules and poljTnorphonuclear mast cells.

The preparations were smears of bone marrow which were fixed in Helly's Zenker-formol mixture while they were still moist. They were stained in the May-Griinwald mixture, in Ehrlich's triacid and indulinaurantia-indulin mixtures, and in Dominici's coml>ination of eosinorange G-toluidin blue. With all of these methods the mast leucocjies and their myelocytes were easily distinguished from the eosinophil leucocytes in all stages of their evolution.

30. (a) Models of the gastric mucosa in rat, pig, and sheep emhrijos; (h) Electrically heated instruments for making wax models; knife for cutting plates smoothing-iron. Chester H. Heusek, The Wistar Institute of Anatomy.

31. Model of a 2 mm. human embryo. N. W. Ingalls, Western Reserve University, C'leveland, ().

32. Plans for a new anatomical laboratory in Cincinnati. Henry McE. Knower, University of Cincinnati.

33. (a) Models showing the escape of ovum from uterine canty in Geomys; (6) An improved microscopic lamp. Thoalvs G. Lee, Universit}' of Minnesota.

3/i. Degeneration in thirty different segments of the spinal cord of a dog, following a mesial section for one centimeter at the level of the cervical nerve. Burton D. Myers, Indiana University.

35. (a) Model of the conus of the frog' x heart; (b) A trilocular heart u^ith pulmonary stenosis; (c) Sections through the canalis craniopharynycus of the rabbit; (d) Sections of auricular region of newborn infant. A. CJ. PoHLMAN, St. Louis University.

3(J. Models illustr(ding the development of the pancreas in Sclachiamf. li. E. ScAM.Mox. I'liiversity of Minnesota.

TllK WATOMIC.VI, KLIOUU, Vol.. 8, NO. -'

/f7.

THE OCCURRENCE OF SUPERNUMER.AJIY SPLEENS

IN DOGS AND CATS, WITH OBSERVATIONS ON

CORPORA LIBERA ABDO:^IINALLS

IV. STUDIES ON HEMAL NODES

ARTHUR WILLLUI MEYER Division of Analumy of the Department of Medicine, Stanford f'niversily

TWELVE FIGURES

In a report on 80 autopsies on infants published in 1895, Jolly (12) states that he found supernumerary spleens present in 25 per cent of the cases. In 2 of the 8 cases two supernumerary spleens were found. The supernumerary spleens in these 8 cases were irregular in form, generally polyhedral and of the size of a hazel nut. In the other 14 cases they were regularh' rounded and easily distinguished from lymph nodes by their color which was that of the main spleen. The}' were usually located on the inferior surface of the gastro-splenic ligament.

If Jolly's findings in these 80 autopsies on infants and children, ranging in age from the newborn to fourteen years, can be considered as representati\e, then the experience of most anatomists would, I think, confirm the old statement that supernumerary spleens in man are much more common in early than in late life. Haberer (8) also came to this conclusion which would seem to be contradicted by Jolly's statement that there is an apparent augmentation in volume witli increasing age and that if such is the case accessory sj)leens ai(> apparently not transitory organs. No doubt Clriiveilhier's conclusion that for \arious reasons they are more difficult to recognize in the adult is correct; but it seems open to question, whether an actual tlegeneration or even an atrophy due to age, takes place as Picou (15) thinks is indicated by the fact that it is the rule for acces.^ory organs to atrophy and disappear completely with age. The only direct evidence suggesting a possible atrophy of supernunuMary spleens obtained in

147

THE AN'ATOMICAl. KF.CORU, VOL. 8, NO. 3 MARCH, 1914

148 ARTHUR "WILLIAM MEYER

the examination of the series of domestic animals reported on here, was found in the case of certain peculiar and questionable pedunculated masses described lielow. However, in these appendices the abnormal circulatory conditions arising from the presence of a long, slender, occasionally twisted pedicle might well be responsible for the fibrosis which existed.

The lack of information regarding the occurrence of accessory spleens in some of the domestic animals — especially dogs and cats — became fully apparent to me some j^ears since in examining the literature on the expermiental production of spleens and so-called hemoljuiph nodes. Moreover, since none of the investigators who reported the experimental production of hemoIj-mph nodes or spleens, as judged by their own publications, had adequately informed themseh-es upon this \'er3^ important question, the conclusions which they reached regarding the new formation of spleens in the omentum or on the peritoneum, after splenectomy, are necessarily open to serious doubt. Foa (4) was the first to question the validity of Tizzoni's (18, 19) conclusions regarding the new formation of accessory spleens after splenectomy. Tizzoni, it will be recalled, excised the spleen in four dogs and found 60 to 80 accessory spleens in the great and gastro-hepatic omenta 2, 54 and 90 days respecti\'ely, after operation. Although no examination of these animals had been made before operation, Tizzoni for wholly insufficient and incorrect reasons nevertheless concluded that these spleens had formed de novo. Foa, who had also called attention to the fact that such small nodules as described by Tizzoni are also found in dogs with entirely normal spleens, apparently did not publish anything further on the subject, but Tizzoni, who was very evidently piqued, was roused to great acti\ity, for he published the results of 40 necropsies a few weeks after the formal presentation of Foa's suggestions. In this paper Tizzoni (20) lays special emphasis on the fact that these necropsies were done at the Veterinary School of Bologna in the presence and with the aid of his excellent friend Gotti.^ The astonishing thing is that although 262 accessory

' Tlie inference is clear, of course, and I mention these details simply because Tizzoni's experiments have been accepted for decades.

SUPERNUMERARY SPLEENS AND CORPORA LIBERA 149

spleens were found in four out of these fort}^ dogs Tizzoni nevertheless says that all his previous conclusions are confirmed ! Tizzoni believed that in these four dogs nature herself had done a partial splenectom}- b}- the development of chronic interstitial splenitis. ^loreover, he performed splenectomy on a dog that had accessor}' spleens and although this animal died of an infection "before the usual results could manifest themselves" he nevertheless concluded that the results obtained in this animal were sufficient wholly to warrant his former conclusions! Tizzoni also failed to state what the results in this case were and then stated that the accessor}- spleens which form as a result of splenectomy always arise as !Malpighian corpuscles which become surrounded by pulp later, while on the contrary, in the case of those that arise as a result of pathological conditions, the pulp forms first and the rest of the spleen from it.

In ^lay, 1882. Griffini TG) reported a series of experiments on the regeneration of small, experiment alh'-produced defects of the spleen in 14 dogs and added that in a few cases he noticed a new formation of spleens from the great omentum or from the spleen itself because of conditions not yet determined. However, Griffini also failed to give any further details regarding these accessory spleens.

A year later Tizzoni (21) reported that he did splenectomies on two dogs which possessed accessor}- spleens before operation as a result of disease." In one animal which was killed six months after operation there was no increase in size and number of the accessory spleens previously present in the great and gastrosplenic omentum, but there were many newl}' formed spleens in the gastro-hepatic omentum, in the lateral ligament of the bladder, in the plica Douglasii, in the ischio-rectal fossa, in the serosa of the stomach and in the central tendon of the diaphragm. In the second animal killed seven months after splenectomy, Tizzoni concluded that there was perhaps an increase in size and number of the accessory spleens previously present in the great and gastro-splenic omentum and that in adtlition other newly formed spleens in all stages of de\el(ipment were found as in the previous animal. Since the first annual had suffered from post

1")() ARTHUR WILLIAM MEYER

operati\p local peritonitis Tizzoni concluded that these inflammatory processes inhibited the formation of accessory spleens in the g;astro-splenic and jrreat omentum and lead to their formation elsewhere.

Even granting that Tizzoni was still unbiased and not on the defensive, it is perfecth' evident, to be sure, that all the additional accessory spleens which Tizzoni regarded as having formed de novo because of splenectoni}^ may just as well have formed because of conditions responsible for the existence of accessory spleens before the operation. Hence splenectomy may not have been a factor at all. The same objection holds for the increase in size.

A year later Tizzoni (22) published a series of conclusions regarding accessory spleens drawn from 60 autopsies, details regarding which he does not give. These conclusions repeat all the older conceptions regarding accessory spleens and emphasize the fact that the new formation of accessory spleens always results from a chronic interstitial splenitis. Tizzoni also draws further distinctions between spleens formed experimentally and as a result of pathological conditions. Since no new facts are presented in this two-page article and since many of Tizzoni' s conclusions can easily be shown to be untenable they will not be discussed here.

During June, 1883, and in 1884 Griffini and Tizzoni (7) reported that 'in some instances,' they found newly formed nodules on the main spleen and in the great omentum in a series of 97 partial excisions of the spleen. The pieces excised were small (4-15 by O-20 mm.) and the dogs were killed from 40 hours to 89 days after operation. In this article which the authors call a resume, the}' gi\'e no details whatever, nor do they rule out reddened l^^mph glands. This joint resume was followed by another resume by Tizzoni ('23) in which he declared that he wanted to test especially what would happen if splenectomy were done on dogs in which accessory spleens had previously formed as a result of disease of the main spleen. This he considered necessary in spite of the fact that Tizzoni had on at least two previous occasions experimentally tested and reported definite—very definite — conclusions

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regarding this very matter. Tizzoni again gi\'es no details regarding tliese dogs — how they were selected, how many and how large the accessory spleens, how they were measured and where located, etc., etc., yet he reported that he found an increase in the number and \'olume of the nodules previously present in the gastro-splenic and great omentum of the two dogs on which splenectomy was done. The experiment was limited to two dogs Ver la difficulte d'avoir des chiens qui se trouvent dans les conditions requises." The same objection urged above apphes, to be sure, to these two experiments for in these cases also the conditions responsible for the formation of accessory spleens before operation may have been responsible for their continued formation after splenectoni}- unless one assumes what Tizzoni does not that the effect of these processes is limited entirely to the main spleen, for Tizzoni reported the existence of identical pathological processes in accessory spleens. Hence it seemed likely that Foa was correct when he suggested what Luschka had previously asserted, that accessory spleens are found in animals having wholh' normal spleens.

In a final article Tizzoni (24) reported on 29 dogs in only four of which he found accessory spleens and never more than three in any one animal. The interesting thing in this article is the finding of the same pathological processes in the accessory as in the main spleen and the existence of a macroscopic zone of infiltration around some of the accessory spleens. Tizzoni again concluded that these findings confirm all his previous conclusions.^

To determine the incidence of accessory spleens a large series of cats and dogs were carefully examined in connection with studies on hemolymph nodes in the domestic animals. The results were (juite surprising for in a series of 98 cats of both sexes, of all age.s, in all stages of pregnane}' and in varying states of health and nutrition six contained one supernumerary spleen, one contained two, and one each (i, 59, IGO and 195 supernumerary spleens respectively. Hence 11.2 per cent of these cats contained accessory spleens and the total number of spleens found in these

A fuller discussion of the cx|)crinicntal proiluction of accessory spleens and heinal noilos by the writer will he found in the Jour. Exp. Zool., February. 1014.

152 ARTHUR WILLIAM MEYER

thirteen animals was 425. The ages of the cats in which the accessoiy spleens were found varied approximately from two to seven j-ears and was considerably higher than that of the dogs. None were found in very 3'oung cats although a careful search was made, and although the total number of animals examined to date is 98, no relation between the occurrence of supernumerai'\' spleens and sex, pregnane}- or Siuy other condition was noticed.

The o\'erwhelming majority of the accessory spleens were located on the great omentum but in one case in which six were present all were found near the hilus of the main spleen, on the dorsal surface of the gastro-splenic omentum. Most of them were very small — 0.5 to 2 mm. — ^and many of microscopic size only. A few of the larger ones had the gross appearance of spleens but the rest all looked exactly like hemal nodes. The large ones usually lay near the main spleen or a small portion, of the main spleen which was more or less distinctly marked off from the main mass as a separate lobule, and it is evident that such occasional findings as these would naturally suggest the old conception of fragmentation and daughter spleens.

In the cats in which such a large number of accessory spleens were found a number were often grouped closely together or were fused, so as to form small aggregates but the individual nodes were seldom more than 1.5 to 2.5 mm. in size. The largest were oval but the smallest were spherical specks, many of which could only be distinguished clearly with a hand lens.

In the three cases in which so many supernumerary spleens were present both surfaces of the great omentum were completely studded with them and in one case a few of the larger isolated specimens or groups, which lay in the immediate \'icinity of, or even adjacent to the main sj)leen, might i)roperly be designated as daughter spleens were it not for the questionable relationship thus implied. In two of the three cats having such large numbers of accessory spleens omental adhesions were present on the main spleen and the latter was scarred in one case, but in the third cat the spleen was wholly smooth and normal. In the first two which were houseliokl pets the main spleens were soft, large and deeply red but in the thu'd cat it was small, firmer and

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paler. The disproportion in size between the first two and the third was marked even after allowing for the differences in size of the cats. One of the large spleens also had a distinct lobule about 2.5 cm. square which was attached by its base, but which had no separate blood supply and in no sense formed a transition between the main and the accessory spleens. None of the latter were surrounded by a hemorrhagic area and there was no reddening of the IjTiiph nodes although one or several h-mph nodes which could not be distinguished from accessory spleens because of their red color, were found. By means of injections these were shown to be Ijinph nodes.

In five cats small pedunculated nodes which were first labeled hemorrhagic tags of the omentum were also found, but these because of their bizarre form and somewhat different structure, should perhaps not all be included among supernumerarj' spleens. The pedunculated masses recalled the two pedunculated supernumerary spleens mentioned by Albrecht (1) as having been found upon the peritoneal surface of the upper portion of the rectum in man and "the very small round nodule" found bj^ Schilling (17) on an appendix epiploica of the descending colon as well as the ahnost pedunculated nodules" mentioned by Tizzoni (19) . The two pedunculated nodules mentioned by Albrecht w;ere said to have the size of a hemp seed.

In several instances the pedicles of the small occasionally pyriform nodules found in these cats were relati\-ely long and so slender as to be barely visible to the unaided eye. The gross appearance of these hemal omental appendages in both the dog and cat, is well shown in figures 1 and 2. Although the short, thick fatty pedicle of the one from the dog shown in figure 2 is directly continuous with the fat of the great omentum, it and its nodular hemorrhagic extremity are free and rest on a very thin and fenestrated portion of the omentum. On the dorsum of this pedicle a vein whicli ended in the hemal nodule was easily seen with the unaideil eye but no artery was visible anywhere. The dt^ marcation between the nodule and the fat of the pedicle was very sharp in this instance but such is not always the case, as is well shown in figure 1 . whicli represents a nuich smaller but similar

154

ARTHUR WILLIAM MEYER

nodule from the cat. The pedicle of this appendage was both relatively and absolutely longer. It was also of very much smaller caliber but likewise contained a small vein which although somewhat spirall}' arranged because of the twisting of the pedicle, was nevertheless distinctly visible in part of its course as is shown in the illustration. The actual measurements of the node after fixation were 1 by 1 .5 mm. No line of abrupt demarcation between the nodule and the pedicle which is 8.5 mm. long is evident and there is also a gradual transition in color and a change in form

Fig. 1 A hemal omental appendage from the cat, showing a portion of the si)irally arranged vein and of the omental fat to which the fatty pedicle is attached.

Fig. 2 Hemal omental appendage from the dog. The short pedicle arising fom the omental fat lies on fenestrated omentum. Xote the vein on the dorsimi

from the one to the other. However, these characteristics are not at all unusual.

These small and ])eculiar appendages were found in various locations on the external surface of the omentum but never on the internal surface in the bursa omentalis. However, since no very extensi\'e series of animals — approximately one hundred — has been examined such a location cannot be excluded with certainty.

The distribution as noticed in these specimens may not be without significance in the origin of some of them. That all of

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them are in very intimate relationship with the surrounding fat is evident from gross examination alone and in serial sections it is seen that in some of them there is no continuous or definite fibrous capsule to delimit the fat from the node. In others, however, there is a very definite connective tissue capsule as can be seen in figure 3 w^hich represents a cross section of the more central portion of the node from the dog, shown in figure 2. In this node a very definite fibrous capsule which was covered by peritoneum on its free surface and bounded b}- the underMng fat on the other, encloses a mass of blood in which two small somewhat eccentrically placed vessels are found. The whole vascular sac is devoid of trabeculae at this point and not a leucocyte or l\Tnphocyte can be found an3"vvhere among the large mass of erythrocytes. The blood which is well-preserved contains no pigment and there are no evidences of destructive changes. In the more proximal portions a more or less well-defined capsule is also present but still further proximalh' the adipose tissue is completely infiltrated with blood and finally the infiltration becomes much slighter and most of the erythrocytes lie near the intercellular boundaries as shown in figure 4 which represents a crosssection of the pedicle in a similar appendage from a cat. Here the infiltration with erythrocytes is comparatively slight but it becomes still slighter as one proceeds still further proxunally until there are no evidences whatever of infiltration and all the blood is contained in vessels. Hence in some of these cases there is a gradual transition from the surrounding fat to conditions as represented in figures 3 and 4 and finally more distally to a structure as repi'esented in figure 5 which shows a jiortion of a transverse section of the same appendage directly through the node. The striking thing about this section is the presence of an exceedingly large amount of connective tissue esj)ecially in the center of the node and of numerous small vessels near the periphery in the vascular area. However, there is very little connective tissue in this area which is bounded externally by a diffuse capsule of consideral^le thickness with much blood between the irregular layers of the connective tissue which form it.

Fig 3 Cro.HHC,tio„<,fan„n,cnUlappo,«laBcfroma.loR. San.c as figure 2.

of which is shown in figure 4.

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From the accompanying illustrations it is evident that some of these pedunculated hemal omental appendages which are really appendices epiploicae in the true sense of the word, resemble supernumerary spleens only more or less remotely structurally, and probably are not such. Since no satisfactory series of transition forms were obtained tlieir genesis must remain largely a matter of surmise. Howe\'er, the hemorrhagic nature of the adjacent fat not infrequently seen, and the transition from this to entirely normal adipose tissue naturally directed special attention to small ill-defined hemorrhagic areas occasionally found in various portions of the omentum. These small areas are usually somewhat elevated and nodular and it does not seem unlikely that further congestion whatever its cause, accompanied by or resulting in diapedesis or hemorrhage and fibrosis might account for some of the non-pedunculated hemal nodes. The fibrosis could, it seems, be attributed to congestion, infiltration and disintegration of blood cells although no such disintegration was observed. The erythrocytes were well-preserved. However, since several undoubted specimens of pedunculated supernumerary spleens were met with in anmials possessing large numbers of these organs and especially since some of the larger isolated supernumerary spleens which also resembled the main spleen in color and surface ai^pearance had a very short pedicle the possibility that some of the hemal nodules on these omental appentlages are really spleens which have undergone fibrosis must be borne in mind.

An inflammatory origin did not seem at all probable, but whatever the genesis of these hemal omental appendages it is evident that only slight tension or torsion would rupture such slender pedicles as those rej)resented in figure 1 and thus convert the nodule into a free body or so-called corpus liberum. Although it is not i)robable that such extremely small vascular nodules as these would give rise to any tlisturbances because they would undoubtedly l)e absorbed rapidly, yet in case of the nuich larger appendages represented in figures t) and 7 such would probal)ly be the case. These two constricted fatty appendages were observed on the omentum of a dog and throw considerable light

V

^

Fig. « Fatty on.ental appon.h^.« fn>.n u '^ J^^^i;;;;;,:;::;,,, ,,„,,„ in figFi^r. 7 Longitudinal section of the fatt> omental M'P^^ ^ ,,l,.ifie.l area, urc .' The circular portion of the sM.allcr one shows the pa.tl> ah

Natural size.

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on the genesis and origin of corpora libera adiposa in the abdominal cavity.

According to Virchow (26) free fatty bodies in the abdominal cavity arise as a result of elongation and torsion of the pedicles of appendices epiplocae — appendices coli — in consequence of the traction from peristalsis. Before the appendices which have been converted into polyp-like structures, become detached, atrophy of the appendix and a thickening of its capsule is said to take place. As a result of the latter the capsule is said to become stratified and even cartilaginous in nature. In consequence of obstruction to and atrophy of the bloodvessels which supply the appendices, a fatty degeneration with subsequent cyst formation and possibly calcification is also said to occur.

Riedel (16) called attention to the fact that a demarcation occurs at the place of torsion, that the distal portion of the appendix is likely to be affected by inflannnatory processes and that it may hence become adherent and form bands which may give rise to ileus. Riedel supports this opinion by several clinical cases and it is particularly interesting that the band in one of these cases in which a free bod}- was present in the abdominal cavity, was 'reddish' in appearance. Microscopic examination, strangely enough, is said to have shown it to be composed of nothing but fat. That the assumption of Riedel regarding the formation of bands by the torn pedicles is j)robably well-fountled is indicated by the wiiter's observations to the effect that the distal free extremity of the degenei-ating umbilical vein in the dog and sheep not infrequently becomes atlherent to the parietes or to some viscus, and thus forms a band which may persist for considerable periods of time. The detached omphalomesenteric vessels may likewise obtain a secondary attachment'^ before finally disappearing and the same holds for the fringe on the irregular margin of the wide and prominent projecting fold of extra-peritoneal fat lying in the median line and extending from the xiphi^d to near the umbilicus in the cat, dog. etc. Hut the surprising thing in

' Vi(l(> Meyor. Uctroj^rcssivo <li!mm>s in footal vrssols aiul lipainents. Am. .lour. Anat.. 1914. Soiiio ol>scrvations ami ronsidorations on tlic umbilical struoturi's of the nowlxun. Am. .lour. (M>stotrics, 1914.

160 ARTHUR WILLIAM MEYER

connection with these bands so frequently seen in dogs and cats, is not their presence l)ut the fact that they apparently cause Uttle trouble, a fact which may, to l)e sure, be dependent upon the horizontal attitude of the animals.

Since the cases of coi-i)ora aliena adiposa abdonunalis found in the literature as far back as 1875, have been recently reviewed by JMliller (14) no further comment will be made on the clinical aspect of this subject. From ]\Iiller's re\'iew and from a splendid discussion and re\'iew by Hoche (11) it is clear that heretofore practically all cases were regarded as arising from detached appendices epiploicae (appendices coli). An exception, however, is the case of Elter (3) in which a large numl)er of smaller and larger calcified nodules, some of which were almost the size of a walnut, were found in the great omentum and the mesentery. Besides, a similar oval nodule 4x3x2 cm. and w^eighing 21 grams had, previous to necropsy, been removed operatively from the rectum where it was thought to have gained a secondary attachment. Elter concluded that the latter had become separated from the omentum or mesentery because of elongation and rupture of its pedicle which he thought was formed as a result of gravity. Elter further concluded that these nodules primarily form as fibromata or fil^ro-lipomata which later undergo necrosis and calcification.

The omental appendages in dogs and cats to which attention has been directed can, however, undoubtedly also give rise to free bodies. This is especially well illustrated by the comparatively

Figs. 8 to 12 Supernumerary spleens from the dog (Canis familiaris).

Fig. 8 Smallest (youngest?) supernumerary spleen found in the omentum of a dog. It is in connection with a vein only and contains a few lymphocytes but no free erythrocytes. X lO.W.

Fig. 9 A portion of a small sui)eriminorary spleen from the omentum of a dog showing the relations of the artery and the variations in the capsule. X 1000.

Fig. 10 A section of the smallest supernumerary spleen foimd containing both a vein and an artery and free erythrocytes. X 020.

Fig. 11 A portion of a supernumerary spleen showing the absence of a distinct capsule. X 410.

Fig. 12 A portion of a supernumerary spleen which is practically a sac of blood. The infiltration of the extra-capular region with erythrocytes and the relation of the surrounding fat are well shown. X 300.

'r^tHfe.

"SX

I

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1()2 ARTHITR WILLIAM MEYER

large, constricted fatty omental apj)cn(.lages from the dog represented in figures 6 and in section in figure 7. The form of both of these seems to suggest that they were moulded somewhat by peristaltic action. That represented in figure 7, which is 6.7 cm. long and approximately 1 cm. in diameter at the base, is slightly flattened and tapers to a somewhat nodular pyriform extremity a little darker in color than the rest. The markedly constricted neck which is only 2 mm. broad and 1 mm. thick is composed only of j)erit()neum and fat. No vessels whatever are visible in it or in the appendix itself. Nevertheless, the fat is practically normal in gross ajipearance and consistency and is not surrounded by a thickened capsule. On the other hand the smaller one represented in figure 7 is much firmer, yellowish in color, contains calcified areas^ and is enclosed in a somewhat thickened capsule which is cartilaginous in consistenc}^ on one side near the base. The largest apparently c/wndrified area is found directly distal to the thin, broad, flattened neck which again is non-vascular and composed almost entirely of serosa.

Since both these appendages are attached by such slender necks it is easy to see that they would ere long have been detached completely and become free bodies. Because of their size it is more than likely that degenerati\'e processes would have given rise to some abdominal disturbances unless calcification could have prevented putrefactive changes. Aloreover it seems to me that these specimens show that necrosis and calcification do not necessarily occur before se})arati()n of an appendix and that there may be no congestion. The}' also seem to indicate that fil)rosis is not necessarily present and that the pedicles may be so extremely short as to make the formation of bands after separation very unlikely. From several instances in which thickened calcified areas one or more centimeters in size were found present in the omentum it is also suggested that local calcification may be a cause in the formation of some of these appendages and hence may precede rather than /oZ/ow appendix and pedicle formation and segregation.

These are (•(intaiiicd in the hasal circuhir portion and hjok a trifle darker in the right half of the smaller ai)i)endafie in fi^;. 8.

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In a series of 67 dogs of vandng ages and conditions two dogs contained 1 and one dog each, 4, 11, 18 and 787 supernumerary spleens respectively. That is, 8.9 per cent of these dogs contained supernumerary spleens and the total number found was 821. The ages of the dogs in which supernumerary spleens were found ranged from four to five months to four to seven years but most of them were young animals, which was not the case in cats. In three of the dogs the supernumerary spleens were limited to the great omentum and in two animals they were practically all surrounded by a somewhat irregular hemorrhagic zone in the middle of which the well-defined nodule lay. In one instance in which only four supernumerary^ spleens were present all were located in the mesentery but in the dog possessing 787 they were found mainly in the great omentum. Some were, however, located on the gastro-splenic omentum and a number also in a fatless fold of peritoneum extending from the spleen to the diaphragm and on the latter itself. Several were also found in the fat near the left kidney. In two instances pedunculated spleens were present. The size of the supernumerary spleens in the dog varied similarly as in the cat and only a very few of them possessed the characteristic color and surface of spleens. In fact, although less variable in color most of them looked like small hemal nodes. Only a few were more than 1 to 2 mm. in size, and as was the case in cats, all, except four, which were located in the mesentery, were found in the greater or lesser omentum.

Several investigators also reported the finding of supernumerary spleens in the pancreas. In four of these 98 cats small dark red slightly elevated areas were noticed in this organ. Two of these cats were only a few days old and the other two were kittens. In all cases these hemal areas which were onlj- a few millimeters in size were indistinguishable from hemal nodes or supernumerary spleens macroscopically. Upon microscopical examination they were, however, found to have no capsule and were hence not delimited from the sin-rounding glandular tissue. In two instances they were composed almost exclusively of erythrocytes which lay in an inconspicuous connective tissue frame

THE ANATOMICAL RECORD, VOL. S, NO. 3

164 ARTHUR WILLIAM MEYER

work containing some lynipliocytes. All of these are^s were irregular and extended between the lobules of the pancreas in various directions. In two cases a small circumscribed area composed wholly of l^inphocytes was also contained in them. Tliese had the appearance of Ijiiiph follicles and since the surrounding blood contained more lymphocytes than in the other cases this gave to these hemorrhagic areas more of the appearance of splenic tissue. Although no remnants of pancreatic cells were contained in the latter I am nevertheless inclined to regard some of them as due to hemorrhage rather than as accessory spleens. It is true that they are rather atypical, for signs of degeneration of erythrocytes were not present and they contained few leucoc\^tes. The lymph follicles or nodules contained in one are difficult to account for on the basis of hemorrhage but the entire absence of a capsule and the fact that these areas differed from supernumerary spleens in certain other respects make me hesitate to consider them as such for such an interpretation w^ould seem to imply that they arose de novo. However, in one cat, an adult female two years old, No. 102, three spleens were found in the right extremity of the pancreas. All were unmistakably spleens. The largest and most prominent was imbedded quite completely, while the two smaller were visible only over an area of 1.5 to 2 mm. of their surface. Their size ranged from 1.5 to 3.5 mm. In the largest about a dozen Malpighian corpuscles were plainly visible on section after fixation. Most of these were of the same size as those in the main spleen which although not sclerotic or pale was unusually- small for the size and condition of the animal. There was nothing peculiar about the lyniph nodes in this cat or of those in the three kittens to which she had given birth about six weeks previously. All the viscera including the spleen and pancreas were of normal shape and there was no evidence of any developmental anomaly.

Tizzoni spoke of a hemorrhagic zone around some of the accessor}' spleens found by hun in the great omentum of the dog and the same condition was observed by Albrecht in man. In the case of the dog containing 787 supernumerary spleens the

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areas of infiltration were very striking indeed. These hemorrhagic zones were so large and irregular in this dog that it was at first thought that they were due to the fact that the animal had been killed by an intravenous injection of chloroform while under chloroform anesthesia. However, in view of the abo\'e observations of Tizzoni and Albrecht and moreover since similar hemorrhagic areas were found around nodes in several instances in other animals it does not seem likely that they were due to the intravenous injection of chloroform or to the preceding chloroform anesthesia, although these may have made them more prominent. Upon microscopic examination the hemorrhagic areas show nothing but an infiltration of the surrounding tissue with blood cells. Similar isolated areas are sometimes seen in omenta containing no supernumerary spleens and near hemal omental appendages or in the pedicles of the latter. No gradation from these areas into the hemal nodes was noticed and the latter were almost always enclosed more or less complete by a definite capsule. These infiltrated areas also differed from ordinary hemorrhagic areas in the absence of marked degeneration of erythrocytes, of pigment and of much phagocytosis in certain portions.

The lymph nodes in these animals were normal in size and appearance but, as in the cats, occasionally a very red node was seen. The latter and all the thoracic nodes which were very red in one dog, were found upon injection to be hmph nodes. In some cases these were very pale gray instead of red and nothing wTas seen differing in the least from what was foimd in dogs having no accessory spleens. The main spleens were normal and no scars or adhesions or separate lobules were found.

The existence of such large numbers of superninnerary spleens in these apparently normal dogs and cats recalls the pathological case of Albrecht (1) and also the statement of Laguesse (13) that the spleen of se^•eral kinds of selachians is normally divided into an infinite number of completely separated red co-apted perls which project from the mesogastrium. Laguesse also stated that in Carcharcias glaucus as many as 2000 such nodules ha\'e been

166 ARTHUR WILLIAM MEYER

counted. However, in this species there is no main spleen in addition and hence it is evident that the conditions are not all comparable to the above conditions in the cat and dog.

In these dogs and cats the main spleens which were quite regular in form save in two cases, varied somewhat in size but in no case were they abnormall}^ small or diseased. Moreover a 'Zersprengung ' or disruption of the spleen was suggested remotely in but two cases by the accumulation of some of the small nodules in the immediate neighborhood of the body of the main spleen. In one case a small splenic lobule was also present, and another spleen contained a deep scar but in several cases in which very definite and comparatively large cicatrices unaccompanied b}^ adhesions (pseudo cicatrices?) were present no accessory spleens were found. Nor were there any displacements or deformities present in any other organ as in the case of the human being reported by Albrecht. In the latter case in which 400 spleens were scattered all over the peritoneum Albrecht referred their origin to the occurrence of some mechanical disturbance during development. No corroborative evidence for such a supposition was obtained in this series of animals, however, nor was anything seen confirming Schilling's (17) supposition that defects in the spleen are usually associated with anomalies of the circulatory system.

From observations on the spleens of a considerable series of domestic animals it became apparent that some of the so-called scars are undoubtedly pseudo-scars. It was noticed for example that the surface of some spleens showed slight local pitting or ridging of varying degrees. In some cases these fibrous depressions or elevations were irregular with smaller sulci and folds extending laterally from the main sulcus. Such purely capsular folds and depressions can simulate scars very closely, indeed, and hence easily lead to misinterpretations. At any rate, I am firmly convinced that not everything that even closely simulates a scar, is actually such, i.e., has a traumatic origin; for many gradations of such were observed and in but a single case were omental adhesions present. If these considerations are well-founded it follows, to be sure, that the hypothesis which attributes the origin of accessory spleens to pre-natal traumata

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is made still more improbable. For foetal life this assumption certainly seems out of the question for when one recalls the mechanical conditions in utero it is exceedingly difficult to realize how any trauma sufficient to disrupt the anlage of the spleen or the formed foetal organ, for that matter, would permit survival of the mother even if of the foetus itself. The writer has, for example, seen scores of isolated pregnant uteri containing foetuses in various stages of development, thrown with some force ten to twenty feet on the frozen plank floors of abattoirs, without ever having been able to detect a ruptured spleen. In fact, it is surprising how roughly excised unopened uteri can be handled with but slight or no damage to the foetus. Moreover, the liver ruptures far easier. Hence it has always seemed to me that any external force sufficiently strong and well localized to rupture the spleen of the foetus or to disturb it sufficiently to produce fragmentation must be wholly incompatible with survival of the maternal organism.

It will be recalled that Tizzoni (22) concluded that the newformation of accessory spleens in the great and gastro-splenic omenta is always accompanied by special alterations of the main spleen as a result of which portions of the parenchyma cannot be bathed by the blood current. Tizzoni clauned that he always found a more or less circumscript chronic interstitial splenitis present in these cases. He believed that this splenitis probably resulted from ruptures of the spleen which he thought to be especially prevalent in animals with a rapid gait such as the dog and horse and that the extent of the formation of accessory spleens was directly proportional to the lesion. Unfortunately for this conclusion scars and omental adhesions on the main spleen, are usually absent in cases of supernumerary spleens and the main spleens vary greatly in size and appearance both in the gross and microscopically. Some are large, soft and deeply red and others are small, fii'm and pale. The former contain a large amount of blood, many Alalpighian follicles but may have large connective tissue trabeculae. The latter usually contain but little blood except in certain small areas, may ha\'e somewhat more evident trabeculae and few Malpighian follicles hut no changes

168 ARTHUR WILLIAM MEYER

or differences whatever were noted in the structure of the capsules. It is possible, to be sure, that these different characteristics of the spleen may be due to the same cause, one representing the initial and the other the final stage of the process but no evidence whatever was obtained suggesting that traumata constitute that cause. Moreover, the presence of a chronic interstitial splenitis was not confirmed nor any relation established between the probable fleetness of the animal and the occurrence of supernumerary" spleens!

From the above observations and considerations it must be fully e\'ident that the current conceptions regarding the origin of multiple or accessory spleens as found in man, are wholly inadequate or even fanciful when applied to cases in which such extremely large numbers of small isolated nodules are found present remote from a normal main spleen. Indeed, it is hardly conceivable, it seems to me, that numerous portions of an early embryonic anlage could lie dormant so long without undergoing regression even if not development, for many of the nodules found were so small that a section did not fill an oil unmersion field. The structure not only of the smallest but of many others was exceedingly simple, as reference to figures 8 to 12 will show. All the sections shown here were taken from supernumerary spleens found in the great omentum. The structure as revealed by these specimens is quite similar to that of many hemal nodes although for reasons stated elsewhere^ I am not wilhng to insist on their identity at present. All transitions in structure from such a nodule as shown in figure 8 of this plate to nodules containing Malpighian corpuscles and whose structure is indistinguishable from that of the main spleen can be found and it is these things which prompt one to consider a secondary origin. Nor do the other hypotheses considered by Schilling seem any more satisfactory explanations since very small apparently undeveloped, masses are found among others much larger and better developed. Hence, in conformity with the above hypothesis, it would seem to be necessary to assume that an extremely large

'Meyer, Anat. Anz., Bd. 45, 1914.

SUPERNUMERARY SPLEENS AND CORPORA LIBERA 169

number of widely disseminated fragments giving rise to independent anlagen were checked more or less permanently in thenearly development only to proceed independently or simultaneously at a later date or even that they were checked in different stages of their development. Indeed, from a careful histological study of many specimens taken from the great omenta of those dogs and cats which contained the very large numbers of accessory spleens above mentioned one can scarcely escape the impression which caused Tizzoni (19) to conclude that many of them are in process of formation. Moreover, it seems unlikely that they can be regarded as arising from portions of a single dissemination of disrupted anlage. The simplicity of structure of many of them lying remote from and foreign to the location of the original anlage would also seem to preclude such an origin. It is probable, to be sure, that the few cases of lien succenturiatus, and hen lobatus which were observed may have resulted from the separation of a small lobule or lobules of the main spleen by deep fissures as Henle (10) thought. Jolly, too, believed that his findings in infants supported this \'iew which seems also to be confirmed by such cases as that reported by Helly (8) and others. However, it is interesting that Gegenbaur (5) rejected it and it is likely that such cases as that of Albrecht in which accessoryspleens were scattered all over the peritoneum and in which several were also found on the serosa of the rectum and the case of Schilling in which a nodule taken for a spleen was found on the tip of an appendix epiplocia of the descending colon, as well as those observed by Tizzoni in dogs probabh" cannot be accounted for in this way. Nor does the relation between accessory spleens and deformities suggested by such cases as those of Bailie and Cruveilhier and of Otto with 7 and 23 spleens respectively, or of transformation of viscera, especially of the stomach, which was emphasized by Toldt (25) seem to be any better founded. Choronschitzsky's (2) criticism regarding this matter and of Toldt 's statement that the spleen develops in the right mesogastrium in case of transposition of the stomach, seem to be wholly justifioil. Besides, in the case of supernumerary spleens in man empiiasis is usually also placed on the fart that the main spleen is smaller

170 ARTHUR WILLIAM MEYER

than normal and that this decrease in size is somewhat directly j)rop(»rtional to the increase in number of the supernumerary spleens. In Albrecht's remarkable case, for example, the main spleen was onh' the size of a 'walnut' and directly contiguous with a group of accessory spleens at its inferior pole. In these dogs and cats containing these unprecedentedly large numbers of spleens there was no reduction in size of the main spleen. Nor was a gradation in size from the main organ through larger adjacent intermediate ones to the smallest of those farthest removed noticed. The structural characteristics of the smallest of these accessory spleens and their relation to the vascular system reminds one of Choronschitzsky's (2) statement that the earliest anlage of the spleen in the chick is in very intimate relationship to the venous system but has no such relation to the arteries. But these questions as well as the structure of accessory spleens, will be discussed elsewhere. Hence, I shall simply call attention to the fact that experimenters who have reported the formation of accessory spleens or hemal nodes after splenectomy without adequate information regarding the presence of these structures before operation have unwittingly drawn unreliable if not wholly erroneous conclusions and it is, for this reason alone, to be seriously doubted whether the alleged formation of accessory spleens or true hemal nodes — ^not hemorrhagic lymph nodes — after splenectomy rests on any other basis than that of uncontrolled and faulty experimentation. Moreover, it is interesting that Foa for similar and Schilling for entirely different reasons, also concluded that the experiments of Tizzoni, Grifhni and Winogradow led to no conclusive results and that according to Helly, Saltykow and Retterer both decided that the accessory spleens alleged to have been newl}^ formed were present before operation. Since true omental appendages quite incomparable to the fatty appendages of the colon in man, have been shown to occur, one cannot refrain from suggesting that the term 'appendices epiploicae' bo applied to the former instead. This would be using the words with their true meaning and would rid the Basel terminology of another objectionable term. Besides, one can scarcely doubt that omental appendages similar to those here described

SUPERNUMERARY SPLEEXS AND CORPORA LIBERA 171

in dogs and cats occur also in man. Attention is also directed to the fact that since some of these omental appendages which may have a wholly different origin simulate supernumerary spleens so very closely but may not be such, the finding of pedunculated supernumerary spleens especially outside of the gastrohepatic and greater omenta demands closer examination.

LITERATURE CITED

Albrecht, H. 1896 Ein Fall von sehr zahlreichen liber das ganze Peritoneum versprengte Xebenmilzen. Beitr. zur path. Anat. u. z. allg. Path. Bd. 20.

Choronschitzsky, B. 1900 Die Entstehung der Miiz, Leber, Gallenblase Bauchspeicheldruse und des Pfortadersystem bei den verschiedenen Abteilungen der Wierbeltiere. Anat. Hefte, Bd. 13.

Elter, .J. 1902 Rectumtumor und Corpus liberum der Bauchhohle. Beitrage zur klinischen Chirurgie. Bd. 35.

FoA, P. 1881 Sulla cosidetta riproduzione della milza. Com. pres. alia societa med. chir. di Modena, December 2, Accessible in review only. 1884 Centralblatt f. klin. Med. Fiinfter Jahrg.

Gegenbaur, C. 1893 Anatomic des Menschen, Fiinfte Aufl. Leipzig.

Griffixi, L. 1882 Sulla reproduzione parziale della milza. Archivio per le scienze med. Torino, March. Accesible in review only.

Griffixi, L. et Tizzoni, G. 1884 Etude experimentale sur la reproduction totale de la rate. Resume Arch. ital. de Biol., torn. 4.

Haberer, H. 1901 Lien succenturiatus and Lien accessorius. Arch. f. Anat. u. Phys. Anat. Abt., Heft 1.

Helly, K. 1903 Zweigeteilte Milz mit Xebenmilzen, Anat. Anz., Bd. 22.

Hexle, J. 1873 Handbuch der Anatomic des Menschen, Zweite Aufl. Braunschweig.

HocHE, L. 1910 Corps libres, archives de medecine experimentale et d'anatomie pathologique, torn. 4.

JoLLY', J. 1895 Rates surnumeraires chez I'infant. Bull. soc. Anat., torn. 70.

Laguesse, E. 1901 Structure de la rate. Traitc d'anatomie humaine, Poiricr et Charpy. tom. 4, Paris.

MuLLER, E. 1906 Beitrag zu Kcnntniss der Corpora aliena adiposa in der Bauchhohle Dissert. Jena.

Picou, M. 1901 Anatomic de la rate. Traito d'anatomie humaine. Poirier et Charpy, tom. 4. Paris.

RiEDEL 1894 Uber Adhasivontziindungcn in dor Bauchhohle. Langenbeoks Achiv., Bd. 47 (Archif fiir klinischc Chirurgie).

Schilling, K. 1907 Uber einem Fall von multiplen Xebenmilzen. Heidelberg.

Tizzoni, G. 1.*<S1 Sulla reproduzion totalo dolla milza R. Acca«l. doi Linroi, Ser. 3, vol. 10, maggio.

172 ARTHUR WILLIAM MEYER

(19) TizzoNi, G. 1881 Experiences et recherches sur la function hemato poetiquc et sur la reproduction totale de la rate. Arch, ital de Biol., torn. 1,

(20) 1881 De la reproduction de la rate a la suite de processus pathologiques qui ont aboli en partie la fonction de la rate. Arch. ital. de Biol., torn. 1.

(21) 1882 Alcune nuove ricerche sulla reproduzione sperimentale della milza Accad. scienze dell' Instituto di Bologna, November 26.

(22) 1883 Les rates accessoires et la neoformation de la rate a la suite de processus pathologiques de la rate primitive. Arch. ital. de Biol., tom. 3.

(23) 1884 Xouvelles recherches sur la reproduction totale de la rate. Contribution e.xperimentale a I'etude de la fonction hematopoetique du tissu conjonctif. Resume Arch, ital de Biol., tom 4.

(24) 1884 Sulla milza succenturiate del cane e sulla reproduzione della milza per process! patholgici che hanno abolita la funzione di questo viscere. Accad. della scienze dell' Instituto di Bologno, December 22.

(25) ToLDT, C. 1889 Die Darmgekrose und Netz im gesetzmassig und gesetz widrigen Zustand, Denkschriften d. k. Akad. d. Wissenschaft zu Wien, Bd. 56.

(26) ViRCHOW, R. 1863 Die krankhaften Geschwiilste, Bd. 1, Berlin.

ERRATA

Hemal notles in some carnivora an! rodents. Stu lies on hemal no les. III. Meyer, Anat. Anz., No. 12, Bd. 45, 1913.

Page 263, foot-note reference (2) read, Mej'er, Anat. Rec, Phila., 1914; and similarly

Page 268, foot-note reference (l) Meyer, The hemolymph nodes of the sheep. Studies on hemal nodes. I. University Publications, Stanford University, 1914.

THE NOMENCLATURE OF THE CARPAL BONES

J. PLAYFAIR McMURRICH Department of Anatomy, University of Toronto

One of the most striking differences between the Basel Nomenclator Anatomicus and the terminology employed in English text-books lies in the names appHed to the carpal bones. It seemed therefore that it might prove of some interest to trace back to its sources the terminology of the bones and to determine the origin of the differences that became established between the German usage (which' was adopted) and that of French and English authors. The inaccessibility of certain works has prevented a perfect review of the literature, but I have ne\-ertheless been able to reconstruct the history of the terminology with sufficient thoroughness to make the presentation of the results seem worth while, if cfnly as matters of historical interest.

In contrast with the tarsal bones, whose names, with the exception of those of the three cuneiform bones.' date back to classical times, the carpals were late in receiving a definite terminology. By the older authors they were either described very superficially, without any attempt at a characterization of the individual bones, or else they were numbered, usually from the radial to the ulnar side and beginning with the radial bone of the proximal row. This was the mode of designation employed by Vesalius and was the mode in general use for o\-er a century after the publication of the De Fabrica."

In 1653, however, definite names were for the first time applied to the bones by Michael Lyser, who was prosector to Thomas Bartholin in the anatomical theater at Copenhagen and published in that j-ear the first edition of his "Cultor anatomicus," a work that passed through five editions and whose scope is sufficiently indicated by its subtitle, "Methodus brevis, facilis ac perspicua

» The term cuneiform was first applied to these bones by Falloppius.

173

174 J. PLAYFAIR McMURRICH

artificiose et eompendiose huinana incidendi cadavera; cum nonnuilorum instrumentorum iconibus." The work is divided into five books, the fifth being devoted to the technique to be adopted in preparing and mounting skeletons, and it is in connection with this that a nomenclature for the carpal bones is suggested. It may be of interest to quote in full the passage in which the terminology is proposed:

Carpi ossa, si Columbi consilium arripueris, facile metacarpo annectere poteris; is enim in purificatione ligamenta hujus intacta dimittit, ut laboriosa opera ea iterum colligendi supersedere possit, quod et in pedii ossibus observare consuevit, scilicet taediosum nimis ista ossa in situm naturalem colligere, quod vix effectum dare licet, si non aliud sceleton exemplaris loco imitandum tibi proponas, ex quo positum ossium horum dignoscas: impossibile enim est oratione eum manifestare, cum propriis nominibus ossa ista careant. Tentabo tamen an aliquali descriptione. quo ordine conjungenda sint, indicare possim, impositis nominibus a forma eorum depromptis. PoUici subjacet cubiform! simile, sed valde inaequalibus lateribus; trapezoides rectius diceres: Indici trapezium: Medius pro fundamento habet os omnium in carpo maximum et crassissimum, in postica parte capitulum obtinens: Annular! et minimo substat os unciforme, quia interius in manu unci in modum est incurvatum, huic adjacet in latere externo aliud ossiculum, cujus latera quatuor triangula conficiunt, cuneiforme dici posset; cui iterum adhaeret minus adhuc ossiculum pisi sativi magnitudine, parte ea, quae priori objicitur, depressum. Sex ilia ossa ordine recensito connectenda. Ideoque singula l)is acu pertundes, ac filum sicuti per summa metacarpi capita traduces: non tamen in recta linea conjunguntur, sed oblique nonnihil et arcuatim. Bina adhuc supersiint ossa, quorum alterum KOTvXoeides appello, obsinum, quo capitulum maximi ossis recipit : klterum lunatum nomino, quia sinum nactum est semilunarem, quo eidem capitulo occurrit.

From this it will be seen that Lyser termed the first or radial bone of the proximal row the cotyloid, the second lunatum, the third cuneiforme, while the fourth he merely describes as ossiculum magnitudine pisi sativi. In the distal row the first bone is named trapezoides, the second trapezium and the fourth unciforme, while the third receives no special designation but is described as os maximum et crassissimum, in postica parte capitulum obtinens."

But notwithstanding the evident popularity of Lyser's book, it was many years before his carpal terminology began to find

NOMENCLATURE OF CARPAL BONES 175

favor among anatomists. For so far as I have been able to ascertain, it was not until 1726 that it received any definite recognition, the anatomical text-books published before that date, and to some extent even after it, continuing to adhere to the numerical designation of the bones, or else failing to consider them indi\-idually. Thus Bidloo (1685) adopts the former plan, and Cowper (1698) in his reissue of Bidloo's plates with an English text, naturally does the same, while Verheyen (1699) follows the latter, as do also Heister (1717) in his "Compendium" and the English Cheselden in his Anatomie of humane bodies" (1713). Both these works passed through numerous editions, that of Cheselden appearing in sixteen and that of Heister, the protot\'pe of the modern quiz-compend, as many as twelve Latin editions, as well as in five German, four French, two English and a Russian translation. From their popularity it may be presumed that they represent fairly accurately the scope of anatomical instruction in their day, but a hint at a knowledge of the fact that names had been bestowed upon the bones is to be found only in the second edition of the "Compendium" (1727), in which in a footnote the author remarks, "There are some who give names to the ossicles of the carpus, a thing which I regard as unnecessarjand useless (supervacaneum et inutile). If, however, they are to be distinguished and named, I think it should be by number." This, however, is not necessarily a reference to Lyser's work, since it followed the publication (1726) of other works in which a definite nomenclature was adopted.

But the lack of acceptance of Lj'ser's suggestions is shown even more clearl}^ in the fact that works dealing exclusively with osteology, published between 1653 and 1733, make no mention of his nomenclature. Thus, in the "Osteologia corporis humani" of Senguerius (1662) the carpal bones are dismissed with little more than the statement that there are "eight bones, vary varied in form," and Palfijn of Ghent in his osteology, written in the Dutch language (1702), gives a very superficial account of them without names and in his "Anatomic du corps humain." published at Paris in 1726, they are numbered from the ulnar side, beginning with the distal row, and but three bones are assigned

17G J. PLAYFAIR McMURRICH

to the proximal row, the pisiform being mentioned as the eighth bone "hors du rang." Lancisi in his editions of the "Tabulae anatomicae" of Eustachius (1714, 1722) gives no designations to the bones and in the elaborately illustrated "Osteographia" of Cheselden (1733) they are also unnamed. Several other osteoiogical treatises, of this period, such as those of de Pauw (1615) and Guillemeau (1618), I have not been able to consult, but from what has been said above it seems clear that Lyser's suggestions liad been rather barren of results until 1726, even although his book was in sufficient demand to warrant the publication of its fifth edition in 1731.

In 1726, however, two osteologies appeared which have had an important influence on the nomenclature of the carpal bones. One of these was "The anatomy of the humane bones," by Alexander Monro, the first of that name in the University of Edinburgh, in which the description of the carpus is introduced as follows :

Carpus is composed of eight, small spongy bones situated at the upper part of the Hand. Each of these Bones I shall describe with Lyserus under a proper name, taken from their figure because the method of ranging them by Numl^ers, leaves Anatomists too much Liberty to debate very idly, which ought to be preferred to the first Number: or, which is worse, several, without explaining the order they observe, differenth^ apply the same Numbers, and so confound their Readers' ideas.

The names adopted by Monro are, with one slight exception, those that have become familiar to students of English textbooks and are as follows, alternative names, which he assigns to footnotes, being placed within brackets: scaphoides (naviculare), lunare, cuneiforme, pisiforme (cartilaginosum), trapezia, Trapezoides, magnum, unciforme.

It will be seen from this list that while professing to follow Lyser, Monro has departed from his suggestions in certain respects. Thus he substitutes for Lyser's cotyloides the more familiar term scaphoid, giving the Latin equivalent as an alternative; instead of lunatum he uses lunare; a definite name is given to the pisiform with an alternative in cartilaginosum; the Lj^serian

NOMENXLATURE OF CARPAL BOXES 177

names for the two radial bones of the distal row are transposed; and the third bone of that row is given a definite name, magnum however being used instead of the superlative maximum found in Lyser's description. Monro gives no explanation of his modification of Lyser's terms, the transposition of trapezoid and trapezium being especially noteworthy; possibly as Blumenbach has suggested, the original source was not consulted at the time of writing, the terms being applied from memory. But, however that may be, it was ^Monro's application of trapezium and trapezoid and not Lyser's that was adopted by later writers.

The other work of 1726 referred to above was the De ossibus corporis humani" of B. S. Albinus in which an almost entirely different set of terms is used, the bones, in the order in which they are taken above, being named: naviculare, lunatum, triquetrum. subrotundum, multangulum majus, multangulum minus, capitatum and cuneiforme. This gives us the source of the B. X." A. terms, the onl}' difference being in the use of subrotundum for the pisiform and cuneiforme for the hamatum. I have not been able to examine Albinus' Tabulae sceleti et musculorum corporis humani" (1747), but in his earliest edition of the "Tabulae anatomicae" of Eustachius (1744) the terms used are the same as those given above.

We have thus in these works of IMonro and Albinus the source of the usages adopted by EngUsh and German anatomists respectively for the nomenclature of the carpal bones. The French usage appears to date back directly to Winslow, that curious compound of keen observation and mysticism; the son of a Danish clergjanan, destined to follow his father's profession, but later relinquishing theology for medicine and coming to Paris where he became a convert to Catholicism under the tutelage of Bossuet. the Bishop of ]\Ieaux, and eventually succeeded Hanauld in the chair of Anatomy and Surgery in the Jardin du Roi. The names he employed in his Exposition anatomique de la stnicture du corps humain" (1732) are based on those used by Monro. Winslow professes to quote Lyser, but in reality the terms he gives are iMonro's; thus he says:

17S J. PLAYFAIR McMURRICH

Lyserus a donne des noms a chacun de ces os. II a nomm^ du premier Hang; Ic premier Os Scaphoide on Naviculaire; le second Os Lunaire; le troisieme Os cuneiforme; le quatrieme qui est hors du Rang os pisiforme ou Lenticulaire. Dans le second Rang il a nomme le premier os Trapeze; le second os Trapezoide; le troisieme le Grand os et le quatrieme I'os Crochu ou Unciforme.

In the description of the individual bones, however, he modifies certain of these terms, substituting 'semilunaire' for lunare and 'orbiculaire' for pisiform or lenticular and suggesting the appropriateness of the term 'pyramidal' for the trapezoid. Tarin in his "Osteographia" (1753) substitutes naviculare for scaphoide and cuboides for cuneiforme and employs the semilunare of Winslow instead of lunare, but otherwise he follows the terminology of ^lonro, and Sabatier in his Traite complet d'anatomie," which had considerable vogue, follows Monro exactly, except that he uses semilunaire instead of lunare. So too Bichat in his '"Traite d'anatomie descriptive" (1801). The ^'Traite d'ost^ologie" of Bertin (Paris, 1754) I have not seen.

It is unnecessary to trace in detail the further history of the terms in Great Britain and German3\ For the former it is sufficient to state that ^Monro's terms were quickly adopted, although later, probably owing to French influence, semilunare began to supplant lunare. In German text-books towards the close of the eighteenth century it became the custom to employ the vernacular in naming the ^'arious bones, these appearing as Kahnbein, Mondbein, etc., the terms employed being, however, in all cases translations of the Latin ones of Albinus. But the synonomy is always given more or less fully, and sometimes new synonyms were suggested. Thus Soennnerring (1791) suggests triangulare as a synonym for das drei-eckige Bein, lentiforme for das runde Bein, rhomboides for das grosse vieleckige Bein and hamatum for the Hackenbein, this last term later replacing the cuneiform of Albinus, probably from the fact that this name was also a synonym for das dreieckige Bein. It may also be mentioned that Hildebrandt (3d ed., 1804) gives pyramidale as one of the synonyms for the cuneiform and os extra ordinem for the pisiform, latinizing the expression os (hors) du rang applied to it

NOMENCLATURE OF CARPAL BONES 179

by Sabatier (3d ed., 1791) and before him by Palfijn (1726j. It is worthy of note, however, that while the German authors thus generally adopted the terminology of Albinus, Jacob Henle, one of the greatest anatomists that the country has produced, preferred a set of terms more nearly resembling those of ^lonro. His terms (3d ed., 1871) are as follows: Kahnbein, os scaphoideum; ]\Iondbein, os lunatum; PjTamidenbein, os pjTamidale; Erbsenbein, os pisiforme; Trapezbein, os trapezium; Trapezoidbein, os trapezoides: Kopfbein, os capitatum; Hakenbein, os hamatum.

From what has been said it is evident that the terms for the carpal bones employed in the B. X. A., are open to criticism on several counts. They do not represent the usage of the majority of those who are obliged to employ- such terms; if we may allow some weight to priority, they are with one exception antedated by the Lyserian names; and two of them, multangulum majus and minus, are cumbersome and, being binominals, are little suited for the formation of derivative words. It is unfortunate that the Commission did not see fit to adopt the nomenclature used by Henle, substituting perhaps triquetrum for his p^Tamidale. cuneiform being thus left for application solely to the tarsal bones. We should then have had a set of terms of convenient brevity and form and recognizing the historical development of the terminology.

The following is a list of the synonjTiis of tlie carpal bones, so far as I have been able to trace them, together with the name of the author who first used them and the date. In certain cases I have not been able to determine the date exactly, owing to the fact that I have had access only to a later edition of the work in which they occur; in such cases the number of the edition consulted is inserted before the date. The bones are arranged in the usual order.

Cotyloides, Lyser (.1(353); scaphoides, .Monro (1726); naviculare, Albinus (1726).

Lunatum, Lyser (1653); lunarc, ^lonro (1726); semilunare. Winslow (1732).

THB ANATOMICAL RECORD, VOL. S, SO. 3

180 J. PLAYFAIR McMURRICH

Cuneiforme, Lyser (1&53); triquetrum, Albinus (1726): cuboides, Tarin (1753); triansulare, Soemmerring (1791); pyramidale, Hildehrandt (3d ed.. 1804).

Pisiforme, Monro (1726); cartilaginosum, Monro (1726); subrotundum, Albinus (1726) ; os hors du rang, Palfijn (1726); orbiculare, Winslow (1732); lenticulare, Winslow (1732); lentiforme, Soemmerring (1791); os extra ordinem, Hildebrandt (3d ed., 1804); rectum Kirby (in Monro 4th ed., 1828).

Trapezoides, Lyser (1653); cubiforme, Lyser (1653); trapezium, ]\Ionro (1726); multangulum majus, Albinus (1726); rhomboides, Soemmerring (1791); rhomboideus, Hildebrandt (3d ed., 1804).

Trapezium, Lyser (1653); trapezoides, ]\Ionro (1726): multangulum minus, Albinus (1726); pyramidale, Winslow (1732); magnum, ]\Iom'o (1726); capitatum, Albinus (1726).

Unciforme, Lyser (1653) ; cuneiforme, Albinus (1726) ; hamatum, Soemmerring (1791).

NOMENCLATURE OF CARPAL BONES 181

LITERATURE CITED

Albinus, Bernard Siegfried 1726 De ossibus corporis hUmani. Leiden.

1744 Explicatio tabularum anatomicarum Batholomsei Eustachii. Leiden.

BicHAT, Xavier 1801 Trait6 d'anatomie descriptive. Paris.

BiDLOo, Godefroi 1685 Anatomia humani corporis. Amstelodami. A large folio volume illustrated by 10.5 copperplates drawn by G. Laires.se. A Dutch translation appeared in 1690 (Amsterdam).

Blumenbach, Joh. Fried. 1807 Geschichte und Beschreibung der Knochen des raenschlichen Korpers. Gottingen.

Cheselden, William 1713 The anatomy of the human body, London. Other editions appeared in 1722, 1726, 1730, 1740, 1741, 1756, 1773, 1778, 1784 and 1792, and apparently two others between 1756 and 1773, that of 1792 being the thirteenth. Two American editions were brought out in Boston 1795 and 1806, and a German translation at Gottingen in 1790.

1733 Osteographia or the anatomy of the bones, London. Later editions appeared in 1811, 1813, 1822.

Cowper, William 1698 The anatomic of humane bodies. O.xford. Choulant gives 1697 as the date of this, but the copy I examined was dated as above. A second edition appeared from Leyden in 1737, and a Latin edition in 1739 and again from Utrocht in 17.50. This wock was the cause of a bitter controversy between Bidloo and Cowper on the ground that the latter had used Bidloo's plates without sufficient acknowledgment. In his advice to the reader he does state, however, in reference to the plates, "These figures were Drawn after the Life, by the Masterly Painter G. de Lairesse, and engrav'd by no less a Hand, and Represent the Parts of Humane Bodies far beyond any Exstant; and were some time since Publish'd by Dr. Bidloo, now Professor of Anatomy at the University of Leyden."

Heister, Laurentius 1717 Compendium anatomiciim. Altdorf. The editions of this popular work to which I have references are as follows. ' Altdorf and Nuremberg, 1719; .\msterdam 1723; Freiburg 1726; .\lt dorf and Nuremberg 1727; Venice 1730; Nuremberg and Altdorf 1732; Breslau 1733; Altdorf 1737; Altdorf 1741; Amsterdam 1748; Venice 1749j Venice 1755; Nuremberg 1761 ; Vienna 1761 ; Edinburgh 1777. These are all Latin editions and these were apparently more nimierousthanis indicated in the above list, since the 1749 edition from Venice is stated to be the fifth Venetian, from the fourtli .Mtdorfian. The work also appeared in several translations. In German Nuremberg 1721, Breslau 17.33, Nureinbergl741, Vienna 1761 and 1770 and there was also a translation by D. G. F. Claudern from the 5th .Mtdorfian in 17.56. French translations were Paris 1724, 172*). 1735 and 17.5;i, and English editions appeared in London in 1721 and 1752.

Hilueurandt, T. 17S9-1792 Lehrbuch dor Anatonue des Menschcn. Brunswick. A second edition was published in 1798-1800 and a third in 1S04.

182 J. PLAVFAlll McMURRICH

Lancisi, Jo. M akia 1714 Tabulae anatoiiiicat' clarissiini viii Rarthohmiaei Kustac'liii. Rome. A second edition appeared in 1722.

Lyser, Michael 1653 Culter anatoraicus. Copenhagen. A second edition is dated Copenhagen 1665, a third Frankfort 1679, a fourth Utrecht 1706 and a fifth Leyden 1731. A German translation was also published at Bremen 1735, and one into English at London 1740. A brief review of the work with some account of the author will be found in a paper by B. Solgcr; M. Lj^ser's Culter anatomicus in Arch, fur Anat. und Phys., Anat. Abth., 1S90. Supplement.

Monro, Alexander 1726 The anatomj- of the humane bones, Edinburgh. Eight editions of this work were published from Edinburgh bearing dates 1726, 1732, 1741, 1746, 1750, 1758, 1763, and 1782. A French translation was published at Paris, 1759, and a German one at Leipzig, 1761.

Palfijx, Jan 1762 En seer Naauwkeursige Beschrijving der Beenderen van s'menschen Lichaem. Leyden.

Palfix, Jean 1726 Anatomic du corps humain, Paris.

Sabatier, M. 1774 Traite d'anatomie descriptive. Paris. Other editions were Paris 1781, 1791.

Senguerius, Arnoldus 1662 Osteologia corporis humani. Amsterdam.

Soemmerring, Samuel Thomas 1791-1796 Vom Baue des menschlichen Korpers. Frankfort. A second edition appeared at Frankfort 1800, and a third at Leipzig 1839-1845. A Latin translation was also published at Frankfort 1794-1801, and one into Italian at Cremona 1818-1823.

Tarin, M. 1753 Osteographic ou description des os de I'adulte, du foetus, etc. Paris.

Verheyen, Philip 1699 Corporis humani anatomia. Leipzig. This was the text-book most in favor in the early part of the eighteenth century, until it was replaced by Heister's Compendium. I find a reference to a quarto edition, Louvain 1693, but this I have not seen. Other editions were Brussels 1710, Cologne 1712, Naples 1717, Leipzig 1718, Brussels 1726, Amsterdam 1731, Leipzig 1731. A German translation was published at Leipzig 1704 and again in 1714, and one into Dutch appeared at Brussels in 1711.

Winslow, Jacques Benignus 1732 E.xposition anatomique de la structure du corps humain. Paris. Other editions were Paris 1766. Amsterdam 1752, 1754 and 1757. Several English editions were also published, London 1734, 1743, 1749, 1763, 1776 and Edinburgh 1772. A Latin edition was published at Frankfort and Leipzig 1753 and an Italian one at Venice 1767.

BOOK REVIEW

Practical Anatomy: The Student's Dissecting Manual. Bv F. G. Parsons, F. R. (•. S. Imij^., and William" Wright, M.B., D.Sc. F.R.C.S.Eng. In two volumes. New York: Longmans, CIreen and Company; London: Edward Arnold. 1912.

The authors present a two-^■olunl(■ dissecting manual for use by students in their practical work in the anatomical laboratory. They wisely, in those instances in whicli they have used it, have made secondary the Basle nomenclature, which at the present time is impractical for general student use.

Following a brief introduction, there appear in volume 1 some general hints on dissecting, and the authors suggest various appliances that the medical student upon beginning dissection should have in his kit. Among these are a "strop, on which he should strop his knife every ten minutes" — -thus wisely emphasizing the necessity for sharp knives, — "knitting needles," "crochet hooks," and various other homely articles which will be found of real value to those of mechanical temperament and ingenious mind.

The authors advise drawing the parts at various stages of the dissection, a commendable but hardly a practical plan, for the reason that the time now allotted to dissecting in a medical course does not pennit of this desirable procedure. No mention is made of the action of the various muscles, nor is anj' attemi)t made to teach the function of any of the nerves. While this woukl encroach upon the domain of physiology, it would be a valualile addendum to the volumes. The teacliing of structure and function should not be s(>]xirated too widely.

The general plan of dissection is in the main \hv same as that found in other present-day dissecting manuals.

In volume 1 the dissection of the face precedes that of the neck; this is a procedure which has not been found by all to he advantageous. In this section the description of the fascia cervicalis is brief and misleading and its im])ortance is not noted, thus minimizing the real value of an accurate conce])tion of this structure.

On ])age Gl, volume 1, occurs a true 'Briticism.' The analogy is drawn here on tiie one hand between the relaticMisiii]) of the lacunae laterales to the su])eri()r longitudinal sinus and on the other that of the 'Norfolk Broads' to their rivers. Wiiile this is a privilege of autiiorship. at the same time it is exerted ;it tlu> (^xjiense of the geographically uninformed non-British student.

The parathyroids (])age 97. vol. 1) are ile.seribeil as 'embeddcil' in the thyroid gland and as seldom seen in the dissecting-room, while no UKMition is made of their blood su]>]ily; tiu^ inadequacy of this deserip 1S3

184 BOOK REVIEW

tion is ol)vious. Tlic importance of tlio plica triangularis of the tonsil is lost in the description on page 192, volume 1, this structure being describeil meagerly but not named. The authors incorrectly speak of a fifth ventricle on page 82(), volume 1. The importance of the osteofascial compartments of the thigh is not mentioned, and here again the text is lacking. The student certainly is unable to gain any clear knowledge of femoral hernia from the ])rief and unsatisfactory attempt to e.xplain it on page 381.

\olume 2 continues the same discrepancies and antiquated descriptions which characterize the first half of this work. The illustrations are of the same poor quality as in volume 1, those depicting the interior of the heart (pages 19 and 21), for example, being very crude. The description of the mediastinum is complete and possesses a definiteness which is largely lacking throughout both volumes. The perineum is accurately described but so poorly illustrated that the dissection of this very difficult and obscure region is rendered less clear for the student than is the case in other dissecting manuals.

The illustrations in both volumes are largely poor sketches and many are misleading and wholly out of proportion. On pages 77, 80, 90 and [i2, volume 1, the diagrams are grotesque, and in many instances they are quite difficult of comprehension — inexcusable faults in any book, but especially in a laboratory manual. The type is clear and the paper good. In the experience of the reviewer, the young and inexjierienced student •would welcome and be helped by a clearer blocking out of directions for dissecting. Such information is better imparted and more easily found if a ditTerent font of type is used for this purpose, but in this book no such plan is foUow^ed; the same type is used throughout.

This manual is certainlv inferior to its predecessors, including both those of English and those of American authorship. The chapters appear to be hastily written, and the}' bear the personal equation of authorship to an injudicious and unscientific degree. The reviewer feels that this work in its present form can not be recommended to the student whose limited time for dissection demands the best of assistance; and furthermore, it fails to equal in many and to surpass in any respect other volumes of a like nature now available.

G. F.

/?^

THE NERVUS TERMINALIS IN MAN AND .AIA.M.M.\LSi

J. B. JOHNSTON

Department of Anatomy, University of Minnesota

NINE FIGURES

It is over nineteen years since Pinkus ('94) first called attention to a 'new nerve' attached to the telencephalon of Protopterus, and thirty-five years since the first record of this nerve having been seen in a shark (Fritsch 78). The forms in which this nerve has now been recorded and its chief characters have been briefly summarized in the writer's previous communication ('13). In that paper the existence of a true nervus terminalis in human and certain mammalian embryos was clearly established. At the same time McCotter ('13) pointed out the existence of the nerve in the adult* cat and dog. Huber and Guild ('13) have since studied the peripheral relations of the nerve in the rabbit in late foetal stages and during the first six days after birth.

The purpose of the present note is to call attention to the presence of the nervus terminalis in certain other adult manunals in the hope that a larger number of workers may undertake the study of its central and peripheral relations. At the present time it is clear that at least a part of the ner\o is distributed to the mucosa of the nasal sac and in mammals accompanies the vomero-nasal nerve. A part of the nerve, however, in mammals clearly goes beyond the limits of the vomero-nasal organ. In the rabbit it spreads over a rather wide area of the nasal septum (^Huber and (Uiild). The nerve is usually accompanied by gangli(in cells, which Brookover ('10) believed to be sympathetic in character. Huber and (luild incline to tlio same conclusion. Although the central i-olations of the nerve have been studied Inspecial methods by Herrick ('09), Sheldon ('09) and McKibben

'Nourolopicjil Studios, I'nivorsity of Miiiiiosota. no. ID, Xovoinlior lo, 1013.

IS.-)

THB ANATOMICAL RECORD, VOL. S. NO. 4 .\PRIL. 1914

186 J. B. JOHNSTON

('11) it is still not known whether its fibers are all afferent, or whether some or all of the fibers arise from cells witliin the brain. In the latter case they might be considered preganglionic fibers of the sympathetic system. The present state of our knowledge suggests the probable presence of both afferent and efferent components in the series of vertebrates. The wide-spread presence of the nerve in adult mammals, including man, should add interest to the study of its relations.

The pig. In my previous communication it was stated that the nerve had not been seen in 73 and 90 mm. pigs. Since then it has been found by dissection in numerous pig foetuses ranging from 50 mm. to full term. The brain of the adult pig has not been examined.

The horse. Figure 1 shows the proximal portion of the right ner\iis terminalis in the brain of an adult. The figure shows a small portion of the basal surface of the brain between the olfactory trigon and the median fissure. A part of the anterior cerebral artery is seen in the right hand part of the figure. The plexus of small vessels lies immediately upon the brain substance, the nervus terminalis lies outside of them and is in turn co\'ered by the pia. The nerve has about fourteen rootlets which enter the brain along the rostral and medial border of the riiedial olfactory tract. The rootlets unite by twos and threes and eventually form a common nerve trunk. Upon the largest one of three main roots into which the rootlets unite, as seen in the figure, there is an obvious ganglion. The nerve trunk extends forward nearly parallel with the olfactory peduncle to a point opposite the rostral border of the olfactory bulb, where it is lodged in the pial septum between the hemispheres. Here the ner\'e had been cut off in removing the brain from the skull.

The nerve of this side was removed after drawing and cut into three pieces for staining. The distal piece was treated with ^•om Rath's picro-osmo-palatino-acetic mixture, cleared in cedar oil and mounted in damar. It contains three fairly well medullated fibers and .seven or eight fibers which were lightly and irregularly blackened. The middle piece was stained in a mixture of nigrosin and acid fuchsin but a differential staining of nerve fibers

NERVUS TER.MINALLS IN MAX AXD .MAMMALS

187

and connective tissue was not obtained. The proximal piece included a part but not all of the ganglion seen in figure 1. The piece was stained in neutral red. A number of cells were found scattered along this piece and the portion of the ganglion consisted of about twenty closely packed cells varying in size. All

Fig. 1 Root of the ncrvus tonninalis in tlio horse, right side. Description in text.

the cells had large nuclei with prominent nucleoli, .\lthough the Nissl bodies were not clearly stained, owing to unsatisfactory fixation, there is no doubt that the colls are nerve cells. Two nerve cells were seen also in the piece stained by nigrosin.

The nerve on the left side of this brain is similar to this although it differs in the number and arrnngement of rootlets.

188 J. B. JOHNSTON

The sheep. Three brains of the adult sheep have been examined. The nerve was not found in the first but was present in the other two. In one of these brains (fig. 2) there was a single strand on the right side and two strands on the left. One of the latter strands presented three conspicuous ganglion-like enlargements. Upon staining and mounting these proved to be true ganglia. The nerve of the right side contained single ganglion cells scattered along its course, two collections of six or eight cells each and a ganglion at its distal end larger than any one of the three on the left side. A piece of the left nerve, treated in vom Rath's fluid, showed a single lightly medullated fiber.

The porpoise. I am indebted to ]\Ir. W. F. Allen of this laboratory for the brain of a porpoise (Phocaena) preserved in Bouin's fluid. The brain of the porpoise has a very broad, rounded frontal lobe (fig. 3), the optic tracts diverge very widely and the anterior perforated space is greatly elongated from side to side. In the absence of the olfactory bulb and peduncle the topographical relations in this part of the brain must be based chiefly on the extent of the anterior perforated space. Upon the basal aspect of the frontal lobe there are seen beneath the pia seven slender strands which converge forward to a point corresponding as nearly as may be judged to the point at which the nervus terminalis was cut off in the horse's brain. Here likewise the nerve had been cut in removing the brain. Proximally the strands enter the brain over a wide area. The most lateral one enters the lateral part of the anterior perforated space. The most medial strand runs along the median fissure and bends up on the medial surface to penetrate the brain in the fissura prima on this medial surface (fig. 4). Two strands follow the anterior cerebral artery in the median fissure and bend laterad with it almost in contact with the rostral surface of the optic chiasma and enter the brain in the depth of the fissura prima on the basal aspect. The nerves of the left side have been described and drawn; those of the right side have a similar arrangement. The nerves are relatively larger than in the horse and are more closely applied to the brain surface throughout their course. They differ also in that the rootlets are flattened strands which run for a longer distance before uniting.

bulb olf.

tr olftned; ■Jrolfht:

lop.

Fig. 2 Ncrvus terminalis in the shcop; g, ganglia; ch.op., optic chiasnm.

Fig. 3 Basal aspect of the brain of the porpoise; s.p.a., substantia perforata anterior. The broken line bounding this rostrally marks a small sulcus occupied by a blood vessel. Three of the rootlets penetrate the brain beneath this vessel. X indicates point at which a root was broken in dissection.

189'

190 J. B. JOHNSTON

The monkey. The brain of ]\Iacacus rhesus and that of M. cynomolgiis have been examined. Both show the nervus terminaUs in characteristic fonn (fig. 5). Rostrally several nerve strands converge on the orbital surface of the frontal lobe (gyrus rectus) between the olfactory bulb and the median fissure and are cut off opposite the anterior end of the bulb. Traced proximally these strands diverge over the surface of the gyrus rectus and bend down into the fissura prima. The number of rootlets is greater in the rhesus, but otherwise the arrangement is essentially the same. The most mesial and thickest strand was removed from the rhesus brain, treated with vom Rath's fluid and stained with carmalum. The strand proved to be so compact that it could not be teased out with needles and only its proximal and distal portions could be examined satisfactorily. The rootlets contained no medullated fibers but in the distal one-fourth of the nerve medullated fibers began to appear and increased until there were fourteen to be seen at the distal end of the portion mounted. Near the distal end was seen a single large, typical ganglion cell. Several small cells in both the proximal and distal ends presented the appearance of nerve cells.

Man. I have examined a foetus of the fifth month, one of seven months, one at full term, a baby of four months and fourteen adult brains.

The five-months foetus had been long in Zenker's fluid or other bichromate solution and was very brittle when it came into my hands. On removing the right hemisphere the nerve of the left side was readily seen as a good-sized whitish strand extending from the fissura prima forward parallel with the olfactory peduncle toward the septum medial to the bulb. The condition of the material made it impossible to follow the nerve peripherally.

Fig. 4 Medial aspect of part of the left half of the brain of the porpoise. The (Jotted line m-h is the line of meeting of the medial and basal surfaces of the frontal lobe. The dotted line below is the profile of the rounded basal surface of the frontal lobe. The three more media! roots are shown. The most medial one enters the brain below the anterior commissure fee); c./., fornix.

Fig. 5 Nervus terminalis in the monkey. The nerves of the right side of Macacus rhesus and those of the left side of M. cynomolgus are drawn; /.p., fissura prima.

XERVUS TERMIXALIS IX MAX AXD MAMMALS 191

V ^

192 J. B. JOHNSTON

The seven-months foetus had been in formalin for at least six years and had not been fresh enough for histological study when preserved. The brain was rather soft and the tissues tough, so that the attempt to trace the nerve into the nose had to be given up. The brain was carefully removed and upon examination under the Greenough binocular, two transparent nerve strands were seen (fig. 6) upon the orbital surface of the gyrus rectus which were cut off opposite the anterior end of the olfactory bulb as in the forms above described. The apparent change in the position of the ner^'e since the five month stage is due to the

.nt

bulh.olf.

triqolf.

Fig. 6 Seven months human foetus, basal surface of the frontal lobes showing the nervus terminalis.

rapid development of the frontal lobe, which has expanded mesad producing a gyrus rectus medial to the olfactory peduncle. The pre-chiasmatic space is filled with a gossamer-like fibrous tissue which had to be removed patiently in order to follow the strands to their point of entering the brain. On the left side one of the strands pierced the rostral border of the medial olfactory tract near the trigon. The other strand divided into two rootlets which ran deeper into the fissura prima (fig. 6). On the right side the nerves were not fully dissected, the anterior cerebral artery being left in position to show the relations.

In the full-term foetus the attempt was made to trace the peripheral course of the nerve. The dissection was made from the face in order to expose the orbital surface of the frontal lobe. The

NERVUS TERMIXALIS IX MAX AXD MA.M.MALS 193

nerve of the left side was found on the gjTus rectus as in other cases. It was a single thick strand readily visible to the naked eye. Traced forw^ard it entered the median fissure opposite the anterior end of the olfactory bulb. Curving somewhat dorsad in the fissure the nerve makes a gentle curve ventrad again and at the same time leaves the surface of the brain, with which it is in contact, and enters the pia mater. At the same time the nerve divides into several strands which flatten out hke a fan. These thin flat strands pierce the pia and enter the tissue of the cribriform plate close to the median plane among the most anterior strands of the olfactory nerve. Here the connective ti-ssue was so tough, owing to the formalin preservation, that the thin strands could not be followed far. Some of them were followed without doubt into the septum, and some appeared to go toward the lateral wall of the nasal chamber, but this was uncertain. The point at which these strands pierce the pia mater is the place where the nerve is cut off when a brain is removed from the skull. The fact that at this point the nerves in the adult brains dissected were either within or very near to the median fissure and imbedded in the pia, suggested the possibility that the nerves might be distributed to the meninges, but the dissection of this specimen was carried far enough to show conclusively that they go down into the septum, and to explain their position in the adult brain.

The brain of a baby of four months showed two strands on the left and three on the right. On both sides the roots entered the brain beneath the medial and rostral border of the medial olfactory tract. The nerve of the left side was stained and mounted, but no ganglion cells were found.

Fourteen adult human brains have been examined and the nervus terminalis found in all. In most cases the nerve is visible under the lowest power of the Greenough binocular without any dissection. It is only necessary that the pia mater shall be intact in the region between the olfactory peduncles and rostral to the optic chiasma. In only one of the fourteen brains was the nerve so small as to be at all difficult to follow. The nerve strands lie just beneath the pia and are visible through it because slightly

194 J. B. JOHNSTON

more whitish opaque than the pia. They are distinguished from small blood vessels because the vessels, even when apparently empty, have a slightly yellowish color. Moreover, small blood vessels are readily traced to the larger ones from which they arise. It is more difficult to distinguish the nervus terminalis from thin bands of connective tissue which lie in or beneath the pia. Most of the connective tissue strands in this region are inserted in the -thick tissue surrounding the anterior cerebral artery or some of its branches in the median fissure, from which they stretch obliquely forward and laterad. The connective tissue strands can be detected by pulling this way and that upon the pia with fine forceps. The strands of connective tissue will be distorted and the appearance of strands will be produced parallel with the direction of tension, while the nerve strands, if present in the area pulled upon, will not be distorted, nor obscured. When the pia mater is pricked through, lifted up with forceps and dissected away it is found that the nerve strands lie beneath the pia but are attached to it more or less closely. The attachment is by means of slender connective tissue strands and in some instances by small bands which pass beneath the nerve in the form of loops or straps. In some, cases the length of the nerve was drawn through one of these loops in order to free it from the pia. With a little care the nerve is separated from the pia and a few minutes suffice to expose the nerve through the greater part of its intracranial course. The dissection of the roots where they bend around the heel-like convexity of the gyrus rectus just in front of the optic chiasma requires more care, especially when the nerve divides into several slender rootlets.

Figures 7, 8 and 9 show the course of the nerve in three adult brains. It runs over the orbital surface of the gyrus rectus and

Fig. 7 Part of the basal aspect of the left frontal lobe in the adult human brain . The blood vessel is a small vein greatly distended with blood. X marks a root broken in dissecting.

Fig. 8 Basal aspect of the right frontal lobe in the adult human brain. Anastomosis of rootlets.

Fig. 9 Similar to figure 8. Nervus terminalis, a single strand with five rootlets on the surface of the medial olfactory tract.

NERVUS TERMINALIS IN MAN AND MAMMALS

195

bulb.olf.4

\ nt.\

/ 1 ■•

chop.

trig-olf.

196 J. B. JOHNSTON

enters the median fissure or lies near it at the level of the anterior end of the olfactory bulb, where the nerve is cut off in removing the brain. As seen- in the figures, the nerve in these cases consisted of one, two, three or four strands. In one case (fig. 7) one of the strands divided into three strands which again united into one. In another case (fig. 8) a slender strand crossed obliquely from one of the main strands to another. It is entirely possible that slender strands would be overlooked or destroj-ed in dissecting and two or three minute strands were seen which are not included in the drawings. In the fourteen brains the type of nerve most frequently met with is that shown in figure 8. In one case the subdivision and reuniting of strands seen in figure 7 was present, together with a large number of very slender strands which ran along the medial border of the olfactory peduncle and bulb. When the nerve consists of a single strand, as in figure 9, it is large enough to be seen and dissected without the use of a lens. In one case it appeared larger than some of the rootlets of the IX and X nerves; but, being a broad thin band, it probably contains fewer fibers than those rootlets.

The point of attachment of the roots to the brain varies considerably. In all cases thus far examined it is in the region of the basal end of the fissura prima, either upon or in front of or behind the medial olfactory tract. In figure 8 the roots are seen converging toward the olfactory trigon, where they seemed to dip beneath the anterior and medial border of the olfactory tract. In figure 9 the single root divides into five rootlets which pierce the medial olfactory tract. The two roots of the other side of this brain had the same position. Two of the three roots in figure 7 have nearly the same position but one of them passes farther toward the median plane.

In position these strands correspond very closely to the nervus terminalis of lower animals and of human embryos previously described. Proof of the nervous character of the strands was sought, however, by removing and staining some of them. In one brain the nerve was found on only the right side. Its two rootlets entered the brain just at the rostral border of the medial olfactory tract where that bends from the orbital to the medial

XERVUS TERMIXALIS IX MAX AXD MAMMALS 197

surface. The roots were pulled out and the entire nerve was stained in neutral red and mounted in damar. It consists of some fifteen or sixteen small bundles of non-meduUated fibers and has imbedded in its course about twelve ganglion cells. These cells occur singly or in twos. There is no larger collection. Each cell has a large nucleus and prominent nucleolus and stains deeply with neutral red. Unfortunately the material was not fresh enough to give a good stain of the Nissl substance.

The nerve on the right side of the brain from which figure 9 was taken was removed and stained as was also the left nerve of the four months baby brain, but no nerve cells were found in either. From the brain shown in figure 8 the ner^-e of the left side was stained in neutral red, while that of the right side was treated with vom Rath's fluid and afterward stained with carmalum. Neither meduUated fibers nor nerve cells were found in this case. The largest nerve found was treated in the same way and teased out carefully. After clearing and mounting in damar there were found four ganglion cells surrounded by numerous sheathcell nuclei. Two cells were in the middle part of the nerve, two at the distal extremity. No medullated fibers were found. Failure to find ganglion cells in some of the other cases may have been due to the fact that the ner\'es were not as well teased out.

From the above facts it appears that a nerve corresponding to the nervus temiinalis of lower vertebrates exists in adult man and several other mammals. This nerve contains some medullated fibers at least in the sheep, horse and monkey, and in the monkey these fibers increase in number distally. In the sheep, horse, monkey and man the nerve contains ganglion cells in at least some individuals. In the sheep and horse there are distinct ganglionic enlargements of the nerve. The failure to find ganglion cells in the other cases here reported has little significance, since only the intra-pial course of the ner\e could be examined. The probability that ganglion cells would be situated farther distally is suggested b}' the condition in the rabbit (Huber and Guild) and by the presence of a large ganglion in the sheep t fig. 2) just at the point where the nerve pierces the pia. rostral to the olfactory bull). The presence and large size of the nervus termi

198 J. B. JOHNSTON

nalis in the porpoise serves to emphasize its independence of the olfactory nerve, which has been abundantly estabUshed by previous work.

The nerve has usually been regarded as a vestigeal structure, but it is an interesting fact that it is larger in man than in many fishes and amphibians. The question suggests itself, for how many million years has the nerve persisted in a vestigeal condition? Further studies are desirable upon the central relations of the ner\-us terminalis and upon its structure and distribution in the nasal septum.

LITERATURE CITED

Brookover, Charles 1910 The olfactorj'^ nerve, the ncivus terminalis and the

preoptic sjinpathetic system in Amia calva L. Jour. Comp. Ncur., vol.

20, no. 2. Fritsch, G. 1878 Untersuchungcn iibcr den feincrcii Bau des Fischgehirns.

Berlin. Herrick, C. Judson 1909 The nervus terminalis (nerve of Pinkus) in the frog.

. Jour. Comp. Xeur., vol. 19, no. 2. HuBER, G. Carl, and Guild, Stacy R. 1913 Observations on the peripheral

distribution of the nervus terminalis in Mammalia. Anat. Rec, vol.

7, no. 8. Johnston, J. B. 1913 Nervus terminalis in reptiles and mannnals. Jour. Comp.

Neur., vol. 23, no. 2. McCotter, R. E. 1913 The nervus terminalis in the adidt dog and cat. Jour.

Comp. Neur., vol. 23, no. 2. McKiBBEN, Paul S. 1011 The nervus terminalis in urodelc Amphibia. Jour.

Comp. Neur., vol. 21, no. 3. PiXKUS, Felix 1894 Uber einen noch nicht beschriebenen Hirnnerven des

Protopterus annectens. Anat. Anz., Bd. 9. Sheldon, R. E, 1909 The nervus terminalis in the carj*. Jour. Comp. Neur.,

vol. 19, no. 2.

A NOTE ON THE CIRCULATION OF THE CORNU

AMMONLS

SAMUEL T. ORTOX From the Laboratory of the Worcester State Hospital, Worcester, Massachusetts

TWO FIGURES

In the course of a study of the distribution of the lesions of general paralysis^ some injection experiments were carried out to determine how great a factor the blood from the carotid s^'stera of cerebral vessels plays in the supply of the cornu ammonis and its associated structures, and the results seem worthy of record.

Six brains in all were injected. Four of these received an injection of a simple aqueous solution of a dye, and two were injected with colored gelatin masses. Immediatel}- on removal of the brain from the body, cannulae were inserted into the basilar and two carotid arteries and normal salt solution from a 5-gallon bottle was allowed to run through the vessels by means of a gravity syphon and under a comparatively low pressure. In one each of the aqueous and gelatine group, the injection was made through the carotid system without opposition from the basilar group. In the others, Beevor's method of simultaneous injection into both trunks under equal pressure was employed.

It frequently happened that the carotid arteries were cut too close to the brain on removal, to permit the introduction of a cannula and in this circumstance the cannula was inserted into either the anterior or middle cerebral and the carotid opening tied, as well as all branches of the carotid system except the anterior choroid. The posterior communicating artery was tied in all instances. In one brain of the six the anterior carotid artery arose from the posterior communicating.

The path of communication from the carotid system to the hippocampal region is hy a l>ianch of the anterior choroid artery

'To appear in (lio American Journal of Insanity.

199

200 SAMUEL T. ORTON

whicli has been found to be of constant occurrence, though variable in size, in both hemispheres of all of a series of twenty-five brains examined, and which reaches the uncus hippocampus to which it gives cortical branches and then, as is apparent in the injected specimens, deeply penetrates the white matter of the cornu for a variable distance.

In all instances there was definite staining by the color carried through the anterior choroid arterj^ of the cortex of the uncus hippocampi and of the central white core of the cornu and while the extent of this coloration varied somewhat in the different specimens of the opposed series, in none of them was it as great as in the brains in which the injection was made unopposed through the anterior choroid.

This discrepancy in the size of the injected area may of course be due to individual variations in the supply which happened to be of greater importance in the two with unbalanced injections, but the explanation also seems tenable that in the unopposed injections the mass penetrated into portions of the field supplied bj^ the posterior cerebrals by means of anastomotic pathways. This type of anastomosis of neighboring cortical fields has been described in areas of the neopallium, that is, between branches of the anterior and middle cerebrals on the dome where the circulation is by no means so strictly endarterial as is the case in the basal ganglia, and the same may be true in this archipallial region.

The accompanying illustrations show the distribution of an unopposed injection in a brain obtained from a case of general paresis about three hours after death. Some clotting had occurred in the large vessels before washing, but the smaller vessels give little or no evidence of plugging.

Figure 1 shows the right temporal pole and hippocampal region with the planes of section and the distribution of the injection mass in these planes. In this case the injection was made through the anterior choroid by way of the anterior cerebral and without a balancing posterior cerebral injection. The posterior communicating artery was tied near its posterior cerebral end and some gelatin found its way into the brain stem through branches of this vessel.

CIRCULATION OF CORNU AMMONIS

201

C

B

Figure 1

THE ANATOMICAL RECORD, VOL. S, NO. 4

202

SAMUEL T. OKTON

amina' ganglionarjs

Figure 2

Figure 2 is a projection drawing of a paraffin section from the specimen shown in figure 1 and illustrates in the larger drawing the relation of the injected material to the various cell and fiber layers and in the smaller the relative richness of the capillar}network containing the gelatin.

EXPEROIEXTS OX THE DEVELOPMEXT OF BLOOD

VESSELS IX THE .\REA PELLUCIDA AXD

EMBRYOXIC BODY OF THE CHICK

ADAM M. MILLER Anatomical Laboratory, Columbia University

JOHN E. McWHORTER Surgical Laboratory, Columbia University

THIRTEEX FIGURES

Those who have studied the early development of blood vessels in the amniote embryo agree that the formation of blood islands in the area opaca of the blastoderm represents the first stage in vascularization. The first blood islands appear about the time the primitive streak reaches the height of its development, in the peripheral part of the mesoderm that hes caudal to the primitive streak. Then, as the 'head process' (primitive axis) develops, they extend forward in the peripheral part of the mesoderm that lies lateral to the primitive streak and 'head process.' The blood islands thus outline a crescentshaped area in the blastoderm — the area vasculosa. Subsequently the cells of these blood islands differentiate into primitive blood cells and the endothelium of the prhnitive blood vessels.

While it is clear that the first blood vessels, namely, those in the area opaca of the blastoderm, arise in situ, the manner in which the region within the concavity of the crescentic area vasculosa, constituting the area pellucida and embryonic body, becomes vascularized has been the subject of much controversy. The views expressed by difTerent investigators can be grouped under two heads, as follows: (1) The vessels that appear in the area pellucida and embryo subsequent to vessel formation in the area opaca are derived from sprouts which grow in

•J03

204 A. M. MILLER AND J. E. McWHORTER

from the already formed vessels or islands. (2) They arise in situ in a manner essentially like that in which the vessels in the area opaca are formed.

The view that vascularization of the area pellucida and embryonic body is the result of ingrowth from the islands or vessels already present in the area opaca has associated with it primarily the name of His (1). This view was acquiesced in by Tiirstig (2), Vialleton (3), and others, and in recent years Evans (4), ^linot (5), and Bremer (6) also have asserted their belief in ingrowth of vessels from the area opaca.

The second view, namely, that the blood vessels of the area pellucida and embryonic body arise in situ and are not the result of ingrowth from antecedent vessels or islands in the area opaca, is most strongly advocated by Riickert and ]\Iollier (7). The recent work of McWTiorter and Whipple (8) on the growth of chick blastoderm in vitro also supports this view.

The writers have here attempted to derive from experimentation on the living blastoderm of the chick some evidence bearing on the question of vascularization of the area pellucida and embr\'onic body. It seemed reasonable to assume that, if the lateral half of the entire area opaca was cut off or in some way removed from the blastoderm at a time when no blood vessels or angioblast (in the sense of Minot and Bremer) had appeared in the area pellucida or embryonic body, and the blastoderm was then allowed to proceed in development, it would be possible to test the validity of the view that blood vessels in the area pellucida and embryo arise in situ and not as ingrowths or sprouts from the antecedent angioblast, blood islands or vessels in the area opaca.

The first step in our study was, therefore, to determine the time to operate on blastoderms in order to exclude the possibility of ingrowth of angioblast, if such there might be, from the area opaca. This was done by examining serial transverse sections of blastoderms from a stage prior to the appearance of the primitive streak up to a stage in which one or two pairs of somites were present. This examination showed that up to the stage in which the 'head process' was clearly visible on surface

DEVELOPMENT OF BLOOD VESSELS IN THE CHICK 205

view there were no cells between mesoderm and entoderm in the area pellucida or embryonic body.

In vievi' of this fact, therefore, we sought to remove the lateral half of the area opaca at a stage not later than the complete formation of the primitive streak, thus allowing a considerable interval between the time of operation and the normal time of appearance of blood vessel anlagen in the area pellucida and embryonic bx)dy. In brief, our aim was to prevent any possible ingrowth of 'angioblast' from the lateral portion of the area opaca of one side. This accomplished, it would follow that any vessels which appeared subsequent to operation, in the remnant of the area pellucida or in the same side of the embryonic body, must have arisen in situ.

TECHNIQUE

Eggs of the common fowl were incubated for twenty hours at a temperature of SS'^C. On removal from the incubator a sufficient quantity of shell was removed to expose the whole upper surface of the yolk. With the aid of the binocular microscope, the stage to which the blastoderm had developed was ascertained and if it was found not to have progressed beyond the primitive streak stage an incision was made with a pair of ver\' fine scissors parallel to its long axis. This incision was made to extend well beyond the periphery of the blastoderm and as close to the primitive streak as possible, without injuring it. In a number of embryos, in addition to the incision already mentioned, another cut was made at an angle of 45 degrees with the first, beginning at the caudal end of the primitive streak and extending diagonally across behind it, as indicated in figure 1. This second cut was made in order to prevent possible vasofactive cells on this side from proceeding fonA'ard along the prunitive streak. As soon as the incision has been made the wound gapes widely, thus very effectively separating the two portions of the blastoderm. At the same time other blastoderms of the same stage were removed from the j'olk, fixed, sectioned serially and stained. A section of one of these control specimens is represented in figure 2.

206 A. M. MlLLKi; AND J. E. McWHORTER

The blastoderm being ready for further incubation, the eggs were carefully placed in small specimen dishes, with loosely fitting glass covers, and surrounded by cotton. The cotton was saturated with some solution, usually Ringer's, the object of this being to keep the exposed surface of the yolk moist and thus to prevent destruction of the blastoderm by drying. These dishes were placed in the incubator and the blastoderms allowed to incubate from sixteen to seventy-two hours longer at a temperature of 38°C. In the majority of cases the incubation period was from twenty to twenty-two hours.

Approximately fifty blastoderms were operated upon. Subsequent development in the incubator took place with remarkably few losses. Not more than 10 per cent of the blastoderms died and these apparently- from excessive drj^ness in the dishes and not from the injury inflicted.

On completion of a given period of incubation, the egg was removed from the incubator and a circular incision was made in the blastoderm beyond the sinus terminahs. With a spatula the embryo, with its adherent membranes, was lifted from its position on the yolk and immersed in Ringer's solution at incubation temperature. Yolk granules and vitelline membrane were removed by gently squirting, through a small pipette, jets of the solution against the embryo. The embryo was then transferred to a glass slide and fixed in either Zenker's or ]\Iann's fluid.

All specimens were photographed in dorsal ^'iew before embedding, for purposes of comparison in the study of sections and in making reconstructions. The specimens were then embedded in paraffin and cut in serial sections of from 5 to 6 microns in thickness. The sections were mounted on slides in the usual manner and then stained by one of the following methods: Heidonhain's or Weigert's hematoxylin, Giemsa's eosin and azur II. or Dominici's toluidin blue, eosin and orange G.

DEVELOPMENT OF BLOOD VESSELS IN THE CHICK 207

GROSS EXAMINATION

After removal from the yolk, some of the blast oderm^s were examined in the warm Ringer's solution under the binocular microscope. Apart from a slight retardation, dev^elopment of the embryonic body had gone on in many cases in an apparently normal manner up to from twenty to twenty-four hours after operation, and the growth of the extra-embryonic area on the uninjured side had followed the usual course. In other cases, in which the incision had been made too close to the primitive streak, the embryo was abnormal in that it lacked a neural fold and mesodermic somites in part on the injured side. The heart could always be clearly seen, and under sufficient magnification the blood cells could be seen circulating in the vessels that had ah-eady joined with the heart.

Embryos that were allowed to develop for more than twentyfour hours after operation usually became abnormal in contour, or even monstrous, although the extra-embryonic area with its blood vessels continued to develop fairly regularly. The heart continued to beat and the circulation went on as usual up to seventy-two hours after operation, the longest period we allowed any of the blastoderms to develop. In the living specimens it was difficult, on account of the thickness of the tissues, to detennine the conditions between the embryonic body and the line of incision. Blood islands were usually \'isible and, in later stages, faint outlines of blood vessels.

In figure 3, taken from a photograph of a fresh specimen twentyfour hours after operation, the embryonic body and the mesodermic somites (9), of which ten pairs are present, are plainly visible. This shows especially well the advance in development during the first day after operation. Compare with figure 1, taken from a blastoderm at the stage of a fully developed primiti\e streak (1) — the stage at which we operated. On the uninjured side in figure 3 the blood islands (10) show distinctly in the peripheral part of the area vasculosa (//). While the vessels in the area pellucida (through which b ood was passing freely) do not

208 A. M. MILLER AND J. E. MeWHORTER

show, the heart {12) is seen at the right of the head region. On the injured side, between the embryonic body and the line of incision, the darker shading represents blood islands (10a).

Figure 4, taken from a specimen in the clearing fluid (cedar oil), shows an embryo which had been allowed to develop fortyeight hours after operation and had grown for that period in a fairly normal manner. The embryo itself is well outlined and exhibits the various parts of the developing ner\^ous system as well as the somites {9), of which 15 pairs are present. The extraembryonic area, with its clearly marked blood vessels {11), is relatively smaller than in most of the other specimens. The heart {12) is very distinct, and, as shown by subsequent study of sections, is unilateral; that is, formed from the anlage of the right side, the left anlage being wholly lacking. On the mjured side the darker areas {11a) between the line of somites and the line of incision represent large aggregations of developing blood cells within developing vessels.

MICROSCOPIC STUDY AND RECONSTRUCTIONS

The reconstructions were made by the graphic method from drawings of serial transverse sections. The drawings were made with the aid of the Edinger projection apparatus, and each section was then carefully studied under high magnification and the corresponding drawing thus verified before being plotted.

In figure 5 is reproduced a partial reconstruction of the vessels and masses of developing blood cells in an embryo which had been allowed to develop twenty-four hours after removal of the left half of the area opaca. All the vessels and blood cells on the injured side are represented. On the uninjured side only the aorta and its branches are shown, the plexus of vessels m the extra-embryonic area being omitted.

On the right (uninjured) side the dorsal aorta {14) follows the usual course. Near its caudal end it sends branches (15) to the extra-embryonic area. These branches constitute the part of the original plexus out of which the vitelhne artery, as well as the aorta, is formed. Two small branches farther cephalad

DEVELOPMENT OF BLOOD VESSELS IN THE CHICK 209

also represent remnants of this plexus. So far as conditions in general are concerned, therefore, the aorta and its branches on the uninjured side developed normally. At its extreme caudal end the aorta becomes continuous with a small solid cord of cells which resemble the cells of a blood island, the endotheUum merging with the superficial elements of the mass.

On the injured side, the dorsal aorta {L'iO) is much smaller than its neighbor of the uninjured side. Through the major part of its course it is a perfectly distinct vessel and possesses a complete endothelial wall (fig. 6, 1/i.a). It contains but few free blood cells. The caudal third is composed in large part of a solid cellular cord (figs. 5 and 7, ll^h). In this cord are four distinct and separate spaces (figs. 5 and 8, IJ^c), which represent the lumen of the vessel. The solid portion is composed of cells which, considering their structure and their reaction to dyes, are identical with the cells in the blood islands of the normal area opaca. It is, therefore, justifiable to conclude that this cord is comparable to a blood island. This seems all the more justifiable in \'iew of the fact that the cells surrounding the spaces in the cord are flattened, unquestionably representing endothelium (figs. 5 and 8, He), and merge with the superficial cells of the solid masses.

From these conditions we may conclude that the caudal third of the aorta on the injured side is in process of formation from a structure identical with a blood island in the same manner as a vessel is formed from a blood island in the area opaca.

The somites and intermediate cell masses on the injured s^ide in the embryo apparently developed in a normal manner (fig. 7, P, 15). The coelom {16), while somewliat irregular, is well formed. The incised edges of the ectoderm and entoderm have fused, the cut thus being healed. The fusion of these two layers is not only interesting in itself but also shows the slight degree of injury inflicted in cutting the blastoderm (flg. 7, x).

Just mesial to the line of incision, in the splanchnic mesoderm, a large blood island extends in an unbroken line from about the middle of the oml^ryo to its caudal end (fig. 5, 10a). Cephalad it is continuous with a small but distinct vessel which opens into

2$$) A. M. MILLElt AND J. E. McWHORTER the caudal (muI of the heart ami is therefore probably analogous to the vitelline vein. The blood island is in every respect similar to the ordinary blood island of the area opaca. The cells are rounded, closely packed together, and possess strongly basophilic cytoplasm. In a few places the superficial cells are somewhat flattened, thus indicating the formation of endothelium. Near the cephalic end of the island are three distinct and separate spaces with perfect endothelial walls. From a point near the caudal end of the island a much smaller cord of cells extends obliquely forw^ard toward the aorta. In this cord are several spaces walled by flattened cells. Between this extensive blood island and the aorta no direct connection could be discerned even under high magnification. Near the caudal end of the large blood island (lOa) are several small isolated islands (10b) and one isolated space (10c) hned with endothelium. In figure 9 is reproduced a reconstruction of the vessels in an embryo which has been allowed to develop for forty-eight hours after removal of the left half of the area opaca. In this specimen the germ layers did not close in ventrally to form a bod}^ wall and gut (see fig. 4; cf. figs. 10, 11 and 12), probably as a result of the proximity of the incision to the axial line. On the uninjured side the extra-embryonic vascular area developed normally, excepting its less than normal size. The dorsal aorta (14) also developed normally, and near its caudal end becomes continuous with the general plexus of vessels in the extra-embryonic area. The vessels of the cephahc portion of the extra-embryonic plexus converge to form a main trunk, which opens into the caudal end of the heart (12) and represents the vitelline vein. The heart itself (12) is unilateral, that is, not fused with a corresponding anlage of the opposite side, and is situated in the splanchnopleure some distance from the medial Hne (fig. 10, 12). This is about the position the lateral anlage of the heart occupies in earlier stages in normal embryos, before it meets its fellow of the opposite side. Examination of this embryo in warm Ringer's solution showed the heart to be beating regularly. The direction of circulation is indicated by the arrows in figure 9. DEVELOPMENT OF BLOOD VESSELS IN THE CHICK 211 On the uninjured side the heart is continuous cephalad with the ventral aorta ffig. 9, 19) which lies close to the entoderm within the embryo proper (fig. 10, 19). In its course the ventral aorta gives off three aortic arches (fig. 9, 20, 21, 22) which open into a vessel lying quite close to the ventro-lateral wall of the neural tube. This vessel, the cephalic portion of the dorsal aorta (figs. 9 and 10, "23), becomes continuous with the dorsal aorta of the trunk (fig. 9, 14)' The dorsal aorta at its cephalic end also communicates with the lateral vein of the head (fig. 9, 24) which lies along the dorso-lateral aspect of the neural tube (fig. 10, 24). The lateral vein of the head (figs. 9 and 10, 24) extends from the fore-brain region, where it receives a branch from the opposite side (fig. 9, 24a), along the dorso-lateral aspect of the neural tube to the level of the caudal end of the heart (12). At this point it expands laterally in the somatopleure into a rather extensive plexus which lies in the region of the amnio-embr^'onic angle. This plexus undoubtedly represents the beginning of the umbilical vein (figs. 9 and 11, 25). At the dotted circles in figure 9 it opens into the caudal end of the heart through two small channels which pass around the coelomic angle. In line with the lateral vein of the head, but farther fonA'ard in the forebrain region, is a large sinus which does not communicate with any other vessel (fig. 9, 24b). The dorsal aorta (fig. 9, 14) along the cephalic part of its course gives off a number of dorsal branches. Some of these apparently terminate in the mesenchymal intercellular spaces along the neural tube. Others pass to the lateral side of the mesodermic somites and terminate in intercellular spaces. Still others passing lateral to the somites, expand at their distal ends, especially in the longitudinal direction, and in a few cavses join one another to form a longitudinal channel. This longitudinal channel, together with the expanded ends of the other laterally directed brandies of the aorta ajiparentl}' represent the beginning of the cardinal vein (figs. 9 and 12, 20). On the injured side of this embryo the conditions in some respects are notably similar to those on the uninjured side; in 212 A. M. MILLER AND J. E. McWHORTER other respects there are certain dififerences which can be accounted for only on the basis of the different circumstances due to the injury. The dorsal aorta (fig. 9, IJ^a) in the major part of the course is a well-formed vessel occupying the same relative position as, but smaller than, its fellow of the opposite side {ilj)', (see also figs. 11, 12 and 13, ll^a). In the caudal region it expands laterally into a plexus of vessels in the remaining portion of the extra-embryonic splanchnopleure (fig. 9, 11a). Cephalad it is continued in a dilated vessel {23a) which is probably the cephalic aorta (23). This is connected with a more dorsally situated sinus (figs. 9 and 10, 2I^c), which represents the lateral vein of the head {2/f). The two dilated vessels together form a relatively enormous sinus which extends along the lateral aspect of the brain almost to the extreme cephalic end of the embryo. The aorta of this side ill^a) is fused with that of the opposite side illi) in three places, as indicated in figure 9; (see also fig. 11, U, 14a). The lateral vein of the head on the injured side (fig. 9, 24.0) is continued caudad by a series of vessels situated lateral to the mesodermic somites and probably equivalent to the cardinal vein of the opposite side (figs. 9, 11 and 12, 26a). At two levels, as represented in figure 9, this series {26a) communicates with the aorta {14^). While for the most part these vessels are lined with a distinct endothelium, near or at their ends they apparently open freely into the* surrounding mesenchymal intercellular spaces, the endothelium merging with the undifferentiated mesenchj'mal cells. A number of isolated lacunae (27), in part lined with endothelium and in part opening into the surrounding tissue spaces, are situated along the lateral aspect of the neural tube. Several other lacunae of a similar character, one especially large (28), are situated more peripherally. The vessels and lacunae on the injured side thus far described are almost destitute of blood cells, a few being present in the large sinus of the head region. The plexus of developing vessels {11 a) in the extra-embryonic splanchnopleure contains, however, DEVELOPMENT OF BLOOD VESSELS IX THE CHICK 213 a great number of blood cells, as shown in figure 13 (11a). In some localities the endothelial wall of the vessel is completely formed, the blood cells being contained within the luman (fig. 13, 11 a). In other localities the conditions resemble those of a blood island in which the superficial cells are just in process of flattening. In figure 9 (29) there is represented a blood island that in section consists merely of an accumulation of round cells with basophilic cytoplasm. Typical blood island structure is also present in the caudal portion of the extra-embryonic plexus (fig. 9, 11 a). In this embryo, as in the 24-hour embryo, the cut edges of the ectoderm and entoderm have fused (figs. 10, 11, 12 and 13). The coelom on the injured side has developed in the form of irregular communicating spaces, which appear distended and suggest an accumulation of fluid here in a region not as freely drained as on the opposite side, where there was uninterrupted circulation in the blood vessels (fig. 7, 16). These two embryos, which we have described in detail, have been selected as typical of the whole of our series of experiments, in all of which we found active vasculogenesis in the area pellucida and embryonic body mesial to our incision. The gap formed as a result of operation remained permanently open, and definitely precludes the possibility of continuous ingrowth of angioblast cords such as Bremer has described in the rabbit. The conditions described show that the removal of the entire lateral half of the area opaca at a stage prior to the appearance of recognizable vasofactive cells or vessel rudiments in the area pellucida does not prevent subsequent development of blood cells and blood vessels in the remaining portion of the area pellucida or in the embryonic body on the same side. On the other hand, it has been found that after this injury blood islands appear in the remaining portion of the extra-embryonic mesoderm and even in the embryonic body: that from these blood islands both endothelium and blood cells are evolved in the usual manner; and that, in adtlition, blood vessels destitute of blood cells doveloj) in l)oth localities. 214 A. M. MILLER AND J. E. MrWHORTER We conclude, therefore, that the same processes are at work in the formation of endotheUum in the embryo and in its membranes, and that the blood vessels of the embryo do not result from the ingrowth of a formed endothelium, but arise in situ from an indifferent mesenchyme. ADDENDUM While this article was in press there came to our attention the work of H. Hahn (Experimentelle Studien iiber die Entstehung des Blutes und der ersten Gefasse beim Huhnchen. I. Teil. Intraembryonale Gefasse. Arch. f. Ent.-Mech. d. Organismen. 27 Bd. 1909). Hahn's briUiant investigation, it seems to us, has not received due credit, if we may judge from the fact that the hematological literature which has appeared since the publication of his work has almost entirely disregarded his conclusions and the evidence on which they are based. It is an agreeable duty for us here to acknowledge the full value of Hahn's prior investigations and results which were obtained through a long series of painstaking experiments and with which our conclusions are in complete harmony. It may be noted, however, that three points of difference obtain in the methods employed in the two cases. (1) Hahn used the electric cautery to destroy the caudal portion of a lateral half of the blastoderm at the early primitive streak stage. We cut off with scissors the entire lateral portion of the blastoderm, making the incision as close to the primitive streak as possible. This procedure reduced to a minimum the amount of damage, thus lessening interference with subsequent development of the germ layers. The probability is that the incision more effectively removes the lateral portion of the blastoderm, with less general injury than burning; and thus the conclusion that the vessels which su])sequently develop within the embryo arise in loco is rendered even more certain. (2) By Hahn's method the site of origin of the heart was probably not destroyed. Bj' the cutting method, if the incision is made close enough to the primitive streak, the site of heart development is removed. In many of our specimens no heart rudiment appeared on the injured side; yet the intraembryonic vessels developed. The view, tlKTcfore, that these vessels are derived from the heart rudiment (Rabl) is no longer tenable. (3) While Halm made in toto graphic reconstructions of some of his blastoderms, lie did not reconstruct the intraembryonic vessels, although figuring th(>m b(>autifully in sections. Graphic reconstructions were made of the vessels in our embryos in a number of cases, from which a more comprehensive view of the vascular system can be obtained. These differences in method have led, however, not to different results, bat to conclusions which are wholly in accord and which seem to leave but little doubt as to the validity of the view tliat intraembryonic vessels are not derived from extrinsic vascular anlagen hut arise in situ. DEVELOPMENT OF BLOOD VESSELS IN THE CHICK 215 LITERATURE CITED (1) His, \V. 1900 Lecithoblast und Angioblast der Wirbeltiere. Abhandl. d. math.-natur. KI. d. K. sachs. Ges. d. Wiss., Bd. 26. Die Lehre vom Bindesubstanzkeim. Arch. f. Anat. u. Physiol., 1882. (2) TtJRSTiG 1884 Untersuchungen iiber die Entwickelung der primitiven Aorten. Schrift. herausgegeben v. d. Xaturf.-Ges. bei d. Univ. Dorpat, Bd. 1. (3) ViALLETOX 1892 Developpement des aortes chez Tembryon de poulet. Journ. d I'Anat., T. 28. (4) EvAXS, H. M. 1911 Die Entwicklung des Blutgefasssystems. Handb. d. Entwicklungsgeschichte des Menschen (Keibel-Mall). Bd. 2, pp. 551-722. (5) AIixoT, C. S. 1911 Die Entstehung des Angioblastes und die Entwickelung des Blutes. Handb. d. Entwickelungsgeschichte des Menschen (Keibel-Mall j. Bd. 2, pp. 483-517. (6) Bremer, J. L. 1912 The development of the aorta and aortic arches in rabbits. Am. Jour. Anat., vol. 13, no. 2. (7) RucKERT AND MoLLiER 1906 Handbuch d. vergl. u. exp. Entwick elungslehre d. Wirbeltiere. Herausg. v. O. Hertwig. Bd. 1, T. 1., pp. 1164-1272. (8) McWhorter, J. E., AND Whipple, A. O. 1912 The development of the blastoderm of the chick in vitro. Anat. Rec, vol. 6. 216 A. M. MILLER AND J. E. McWHORTER Fig. 1 Dorsal view of a chick blastoderm of twentj' hours incubation, showing the fulh' formed primitive streak (1), primitive node (2), area pellucida (3), and area opaca (4). Photomicrograph. (Columbia Embryological Collection, series No. 602.) The line A-B indicates the direction of the main incision made to remove the area opaca on one side. The line projected to C indicates the second incision made in some cases. P"ig. 2 From a transverse section through the primitive streak (/), area pellucida (5), and area opaca (4), of a chick blastoderm of twenty hours incubation (stage of fully formed primitive streak). Photomicrograph. (Columbia Embry ological Collection, series Xo. 611, slide VI, section 40.) 5, Ectoderm ; 6, mesoderm 7, entoderm; 8, germ wall. The Une A-B indicates the main incision made to remove the area opaca (4) ■ ■ ?' rf->-. "T LM7 THK ANATOMICAL RECORD. VOL. 8. SO. 4 218 A. iM. MILLER AND J. E. McWHORTER Fig. 3 Dorsal view of a chick blastoderm which had been allowed to develop for twenty-four hours after removal of the left half of the area opaca in the manner indicated in figures 1 and 2. Photomicrograph of fresh specimen. (Columbia Embryological Collection, series No. 600.) 9, Mesodermic somites; 10, blood islands in splanchnic mesoderm on uninjured side; 10a, blood islands in splanchnic mesoderm on injured side; 11, area vasculosa on uninjured side; IS, heart. Levels at which sections shown in figures 6, 7 and 8 were taken are shown at left of figure. DEVELOPMENT OF BLOOD VESSELS IN THE CHICK 219 Fig. 4 Dorsal viru ul ;i clui-k bhi^iudtiUi uliuh had been allowed to dovelop for forty-eight hours after removal of the left half of the area opaca in the manner indieated in figures 1 and 2. Photomicrograph. (Columbia Embryological Collection, .series No. G13.) 9, Mesodermic somites; //, area vjisculosa on uninjured side; Ua, developing blood vessels in splanchnic mesoderm on injured side; 12, heart; IS, sinus terminalis. Ix-vels at which sections shown in figures 10, II. 12 and 13 were taken are shown at the left. 220 A. M. MILLER AND J. E. MrWHORTER Fig. 5 From a partial reconstruction of the blood vessels and developing blood cells in an embryo which had been allowed to develop for twentj'-four hours after operation. Same embryo as in figure 3. Dorsal view. 10a, Large blood island in splanchnic mesoderm on injured side (cf. figs. 6, 7 and 8, 10a); 106, small isolated blood islands; 10c, small isolated lacuna; 14, aorta on uninjured side; 14a, 14b, 14c, aorta on injured side. Dotted line A-B indicates line of cut edge of germ layers (cf . figs. 6, 7 and 8) ; dotted line D-E lies in mesial sagittal plane of embryo. Levels at which sections shown in figures 6, 7 and 8 were taken are indicated at left of figure. •2-21 222 A. M. MILLER AND J, E. McWHORTER Figs. 6, 7 and 8 From transverse sections of same embryo as in figures 3 and 5 in wiiich the levels of these sections are indicated at the left. Photomicrographs, slide XI, section 12 and slide XII, sections 7 and 35, respectively. 9, Mesodermic somites; 10a, blood island in splanchnic mesoderm on injured side; H, aorta on uninjured side; Ha, 14b, He, aorta on injured side (see fig. 5); 15, intermediate cell mass; 16, coelom; 17, neural tube; 18, notochord. At the point A" in figure 7 the incised edges of the ectoderm and entoderm are shown to be fused. rs- * -*> I •-^1.8 ... Ha,: 14 18 14b 224 A. M. MILLER AXD J. E. McWHORTER Fig. 9 From a reconstruction of the blood vessels in an embryo which had been allowed to develop for forty-eight hours after operation. Same embryo as in figure 4. Dorsal view. //, Vessels in extra-embryonic splanchnic mesoderm (area vasculosa) on uninjured side; 11a, developing blood vessels in splanchnic mesoderm on injured side; 12, heart (unilateral); 14, aorta on uninjured side; 14(1, aorta on injured side; 19, ventral aortic root; 10, 21, 22, aortic arches; 23, dorsal aortic root on uninjured side; 23a, dorsal aortic root (?) on injured side: 24, lateral vein of head on uninjured side; 24a, branch of same from opposite side; 24b, isolated portion of same; 24c, lateral vein of head on injured side; 25, umbilical plexus; 26, cardinal vein; 26a, cardinal vein on injured side; 27, small lacunae lateral to neural tube; 28, large lacunae in splanchnic mesoderm; 29, large tj'pical blood island in somatic mesoderm. Dotted line A-B indicates line of cut edge of germ layers (cf. figs. 10, 11, 12 and 13). Levels at which sections shown in figures 10. 11, 12 and 13 were taken are shown at the left. 22() A. -M. .MILLER AND J. E. McWHORTER Fif?. 10, n. 12 and 13 From transverse sections of same embryo as in figures 4 and 9 in which the levels of these sections are indicated at the left. Photomicrographs. Slide V, section 54, slide VI, section 53, slide VII, section 22, slide VIII, section 38, respectively. 11a, Blood vessels in splanchnic mesoderm on injured side; 12. heart; H, aorta on uninjured side; l^a, aorta on injured side (fused with IJf, in fig. 11); 16, coelom; 17, neural tube (lacking left half in fig. 13) ; 18, notochord; 19, ventral aortic root; ^il aortic arch; 23, dorsal aortic root on uninjured side; 23a, dorsal aortic root on injured side; 2Jt, lateral vein of head on uninjured side; 2IfC, lateral vein of head on injured side; 25, umbilical plexus; 26, cardinal vein on uninjured side; 26a, cardinal vein on injured side; 28, portion of large lacuna represented in figure 9. DEVELOPMENT OF BLOOD VESSELS IN THE CHICK 227 REPRODUCTION OF -MODELS BY THE WISTAR INSTITUTE In ])ractically all the anatomical laboratories where research is conducted, the Born method of wax plate reconstruction has been resorted to as one of the most satisfactory methods of investigating the form and relations of minute anatomical structures. Each anatomical laboratory thus produces a number of models, many of them in\'aluable in teaching the subject to which they relate. Unfortunately, however, there is usuall}' but one model of a given structure in existence, and only the laboratory possessing this model may use it for purposes of instruction. Of late years there has been an increasing demand for replicas of original models, so that each laboratory- might use for teaching purposes not onl}^ the original models of its own production but also those produced in other laboratories. Heretofore it has been necessary to send original models abroad in order to secure replicas. The trouble and expense incurred and the accidents in transporting such fragile articles in connection with conditions difficult to meet have discouraged those desirous of securing models in this manner. In order to overcome these difficulties and make the acquisition of replicas of original anatomical models possible, The Wistar Institute has established a department for what might be called the publication of original models. The work of this department will be done by or under the personal supervision of Dr. B. Eric Dahlgren, a well known expert of wide experience in the production of biological models. The first replica of each model will be made under the supervision of the author. This model will be retained at The Wistar Institute as a guide for the production of others. The Wistar Institute will receive original anatomical models, produce as many replicas as may be subscribed for and distribute them for the actual cost of production. It is believed that this service to anatomy will be appreciated by anatomists engaged in teaching, and that it will be a direct benefit to the students of anatomy who may thus be able to examine more of the original models resulting from the research in our best laboratories. 228 AMERICAN ASSOCIATION OF ANATOMISTS OFFICERS AND LIST OF MEMBERS Officers President G. Carl Huber Vice-President F"rederic T. Lewis Secretary-Treasurer Charles R. Stockard Executive Committee For term expiring 1914 Clarence M. JArKSo.v. Abram T. Kerr For term expiring 1915 Henry MrE. Knower, Irving Hardesty For term expiring 1916 Arthur W. Meyer, Charles F. \V. McClure For term expiring 1917 W arren H. Lewis. C. Judsox Herrick Honorary Members S. Ram6x y Cajal Madrid, Spain JoHX Clelaxd Glasgow, Scotland Camillo Golgi Pavia, Italy Oscar Hertwig Berlin, Germany Alexander INIacallister Cambridge, England A. Nicholas Paris, France MoRiTZ NcssBAUM Bonn, Germany L. Ranvier Paris, France GrsTAV Retzius Stockholm, Sweden WiLHELM Roux Halle, Germauy Carl Toldt Vienna, A ustria Sir William Turner Edinburgh , Scotland WiLHELM Waldeyer Berlin , Germany Members Addison, William Henry Fitzgerald. li.A., M.R.. Assistant Professor of Normal Histology and Emhryology, I'nivcrsity of Pennsylvania. 39S2 Pine Street, Philadelphia, I'n. Allen, Bennet Mills, PliO., Professor of Zocilogy, University of Kansas, Lawrence, Kansas. Allen, William F., A.^L, Instructor in Histology and Embryology. Institute of Anatomy, Cniversity of Minnesota, Minneapolis, Minn. 229 230 AMERICAN ASSOCIATION OF ANATOMISTS Allis, Edward Phelps, Jr., LL.D., Palais de Carnolh, Mentone, France. Haker, Fraxk, A.M., M.D., Ph.D. (Vice-Pros. '88-'91, Pros. '96-'97), Professor of Anatom}', University of Georgetown, 1901 BiUmore Street, Washington, D. C. Baldwin, Wesley Manning,A.B., M.D., Instructor in Anatomy, Cornell I'niver sity Medical College, First Avenue and 28th Street, New York, N. Y. Hardeen, Charles Russell, A.B., M.D. (Ex. Com. '06-'00.) Professor of Anatomy and Dean of Medical School, University of Wisconsin, Science Hall, Madison, Wis. Badert.scher, J.\cob A., Ph.M., Ph.D., Instructor in Anatomy, Indiana University School of Medicine, 512 E. Fourth Street, Bloominglon, Ind. Bartelmez, George W., Ph.D., Instructor in Anatomy, Chicago University, Chicago, III. Bates, George Andrew, M.S., Professor of Histology and Embryology, Tufts College Medical School, Huntington Avenue, Boston, Mass. Baumgartner, Edwin A., A.M., Instructor in Anatomy, Institute of Anatomy. University of Minnesota, Minneapolis, Minn. Baumgartner, William J., A.M. Assistant Professor of Histology and Zoology, Univcr.'iity of Kansas, Lawrence, Kons. Bayon, Henry, B.A., M.D., Associate Professor of Anatomy, Tulane Universitj-, 2212 Napoleon Avenue, New Orleans, La. Bean, Robert Bennett, B.S., M.D., Associate Professor of Anatomy, Tulane University of Louisiana, Station 20, New Orleans, La. Begg, Alexander S., M.D., Harvard Medical School, Boston, Mass. Bell, Elexious Thompson, B.S., M.D., Assistant Professor of Pathology, University of Minnesota, 222 Harvard Street, Minneapolis, Minn. Bensley, Benjamin .\rthur, Ph.D., Associate Professor of Zoology, University of Toronto, 316 Brunswick Avenue, Toronto, Can. Bensley, Robert Russell, A.B., M.B. (Second Vice-Pres. '06-'07, Ex. Com. '08'12), Professor of Anatomy, University of Chicago, Chicago, III. Be VAN, Arthur Dean, M.D. (Ex. Com. '96-'98), Professor of Surgery, University of Chicago, 2917 Michigan Avenue, Chicago, III. BiGELow, Robert P., Ph.D., Assistant Professor of Zoology and Parasitologj'^, Massachusetts Institute of Technology, Boston, Mass. Black, Davidson, B.A., M.B., Assistant Professor of Anatomy, Western Reserve University, Medical Department, 1353 East 9th Street, Cleveland, 0. Blair, Vilray Papin, A.M., M.D., Clinical Professor of Surgery, Medical Department, Washington University, Metropolitan Building, St. Louis, Mo. Blaisdell, Frank Ellsworth, M.D., Assistant Professor of Surgery, Medical Department of Stanford University, 1520 Lake Street, San Francisco, Calif. Blake, Joseph Augustus, A.B., M.D., 108 East 65th Street, New York, N. Y. Blood(;()ou, Joseph C, A.B., M.D., Associate Professor of Surgery, Johns Hopkins Hospital, 904 North Cluirlcs Street, Baltimore, Md. BoYDEN, Edward Allen, Teaching fellow. Histology and Embryology, Harvard Medical School, Boston, Mass. IJitKMER, John Lewis, M.D., Demonstrator of Histology, Harvard Medical School, 4^6 Beacon Street, Boston, Mass. MEMBERS 231 Brodel, Max, Associate Professor of Art as Applied to Medicine, Johns Hopkins University, Johns Hopkins Honpilal, Baltimore, Md. Brooks, William Allen, A.M., M.D., 167 Beacon Street, Boston, Mass. Brown, A. J., M.D., Demonstrator of Anatomy, Columbia University, 437 W. 69th Street, New York, N. Y. Browning, William, Ph.B., M.D., Professor of Nervous and Mental Diseases, Long Island College Hospital, 54 Lefferls Place, Brooklyn, N. Y. Bryce, Thomas H., M.A., M.D., Professor of Anatomy, University of Glasgow, No. 2, The University, Glasgorv, Scotland. BuLLARD, H. Hays, A.M., Ph.D., Instructor in Anatomy and Neurology, University of Pittsburgh Medical School, Pittsburgh, Pa. Bunting, Charles Henry, B.S., M.D., Professor of Pathology, University of Wisconsin, 1804 Madison Street, Madison, Wis. Burrows, Montrose T., A.B., M.D., Instructor in Anatomy, Cornell University Medical College, New York, N. Y. Campbell, William Francis, A.B., M.D., Professor of Anatomy and Histology, Long Island College Hospital, 394 Clinton Avenue, Brooklyn, N . Y. Carpenter, Frederick Walton, Ph.D., Professor of Zoology, Trinity College, Hartford, Conn. Chase, Martin Rist, M.S., Assistant in Anatomy, Northwestern University Medical School, 2431 Dearborn Street, Chicago, HI. Cheever, David, M.D., Assistant Professor of Surgical Anatomj', Harvard Medical School, 355 Marlborough Street, Boston, Mass. Chidester, Floyd E., Ph.D., Instructor in Zoology, Rutgers College, New Brunswick, N. J. Chillingworth, Felix P., M.D., Assistant Professor of Physiology and Pharmacology, Tulane University, New Orlcajis, La. Clapp, Cornelia Maria, Ph.D., Professor of Zoology, Mount Holyoke College, South Hadlcy, Mass. Clark, Elbert, B.S., Associate Professor of Anatomj-, University of Chicago, Chicago, HI. Clark, Eleanor Linton, A.M., Research Worker, Department of Anatomy, Johns Hopkins University, Baltimore, Md. Clauk, Eliot R., A.B., M.D., Associate in Anatomy, Johns Hopkins University, Anatomical Laboratory, Wolfe and Monument Streets, Baltimore, Md. CoGHiLL, George E., Ph.D., A.ssociate Professor of Anatomy, [University of Kansas Medical School, 338 Illinois Street. Lawrence, Kansas. CoHN, Alfred E., M.D., Associate in Medicine, Rockefeller Institute for Medical Research, 315 Central Park West, New York, N. Y. Cohoe, Benson A., A.B., M.B.. Assistant Professor of Medicine, University of Pittsburgh, 705 North Highland Avenue, Pittsbtirgh, Pa. CONANT, William Merritt, M.D., Instructor in Anatomy in Harvard Medical School, 48fi Commontvcalth Avenue, Bostoti, Mass. Conklin, Edwin Grant, A.M., Ph.D., Sc.D., Professor of Zoology, Princeton University, 139 Broadmcad .\vcnuc, Princeton, N. J. Corner, Georcje W., M.D., Assistant in Anatomy. Johns Hopkins I'uiversity, Johns Hopkins Medical School, Baltimore, Md. Corning, II. K., M.B., Professor of Anatomy, Buudesstr 17, Basel, Switzerland. 232 AMERICAN ASSOCIATION OF ANATOMISTS CoiisoN'. Eugene Rullix, 13. S., M.D., Surgeon, Lecturer on Anatomj-, Savannah Hospital Training School for Nurses, 10 Jones Street, West, Savattnah, Gn. CowDRY, Edmund V., Ph.D., Associate in Anatomj', Anatomical Laboratory, Johns Hopkins Medical School, Baltimore, Md. Cr.\ig, Joseph D.wls, A.^L, ]\LD., Professor of Anatomy, Albany Medical College, 12 Ten Drocck Street, Albany, X. Y. Chile, George W., ^LD., Professor of Surgery, Western Reserve University, 1021 Prospect Arenue, Cleveland, 0. Cullen, Thom.\s S., ^LB., Associate Professor of Gynecology, Johns Hopkins University, 3 West Preston Street, Baltimore, Md. Cunningham, Robert S., B.S., A.M., Johns Hopkins Medical School, 716 X. Broadway, Baltimore, Md. CuRTi.s, George ]\L, A.B., A.M.. Assistant Professor of Anatomy, Medical Department of the Vandcrbilt Unirersity, 907 Fir.'^t Avenue, Nashville, Tcnn. D.^HLGREN, Ulric, I\LS., Professor of Biology, Princeton Uniiersity, 204 Guyot Hall, Princeton, X. J. Danforth, Charles Haskell, A.^L, Ph.D., Instructor in Anatomy, Medical Department, Washington University, 1806 Locust Street. St. Louis, Mo. Darrach, William, A.M., ISLD., Junior Surgeon Roosevelt Hospital, Instructor in Clinical Surgery, Columbia University, 47 West 50th Street, New York, X. Y. Davidson, Alvin, M.A., Ph.D., Professor of Biology, Lafayette College, Easton, Pa. Davis, David ]\I., B.S., Johns Hopkins Medical School, Baltimore, Md. Dawburn, Robert H. Mackay, ^I.D., Professor jf Anatomy, New York Polyclinic Medical School and Hospital, 105 West 74th Street, Xew York, N. Y. Dean, Bashford, Ph.D.. Professor of Vertebrate Zoology', Columbia University, Curator of Fishes and Reptiles, American Museum Natural History, Riverdale-on-Hudson, New York. Dexter, Franklin, M.D., 247 Marlborough Street, Boston, Mass. Dixon, A. Francis, M.B., Sc.D., University Professor of Anatomy, Trinity College, 73 Grosvenor Road, Dublin, Ireland. DoDSON, JohnMilton, A.INL, M.D., Professor of Medicine, University of Chicago, 5806 Washington Boulevard, Chicago, HI. Donaldson, Henry Herbert, Ph.D., D.Sc. (Ex. Com. '09-' 13), Professor of Neurology, the Wistar Institute of Anatomy and Biology, Woodland Avenue and 36th Street, Philadelphia, Pa. Downey, Hal, M.A., Ph.D., Associate Professor of Histology, Department of Animal Biology, University of Minnesota, Minneapolis, Minn. Dunn, Elizabeth Hopki.vs, A.M., M.D., Nelson Morris Laboratory for Medical Re.search, 4760 Lake Park Avenue, Chicago, III. EccLES, Robert G.. M.D., Phar.D., 681 Tenth Street, Brooklyn, X. Y. Edwards, Charles Lincoln, Ph.D., Director of Nature Study, Los Angeles City Schools, 1032 West 39th Place, Los Angeles, Calif. Elliot, Gilbert M., A.M., M.D., Demonstrator of Anatomy, Medical School of Maine, 162 Maine Street, Brunswick, Me. Emmel, Victor E., M.S. Ph.D., Associate in Anatomy, Washington University Mcdiral Srhiiol, St. Louis, Mo. MEMBERS 233 Erdmax, Charles Andrew, M.D., Professor of Gross and Applied Anatomy, University of Minnesota, Institute of Anatomy, University of Minnesota, Minneapolis, Minn. EssiCK, Charles Rheix, B.A., M.D., Instructor in Anatomy, Johns Hopkins University, 1807 Xorth Caroline Street, Baltimore, Md. Evans, Herbert McLean, B.S., M.D., Research Associate in Embryology. Carnegie Institution, Johns Hopkins Medical School, Baltimore, Md. Evatt, Evelyn John, B.S., M.B., Professor of Anatomy, Royal College of Surgeons, Dublin, Ireland. Eycleshymer, Albert Chauncey, Ph.D., M.D., Professor of Anatomy, Medical Department, University of Illinois, Chicago, III. Ferris, Harry Burr, A.B., M.D., Hunt Professor of Anatomy and Head of the Department of Anatomy, Medical Department, Yale University, 393 St. Ronan Street, New Haven, Conn. Fetterolf, George, A.B., M.D., Sc.D., Assistant Professor of Anatomy, University of Pennsylvania, 330 South 16th Street, Philadelphia, Pa. FiscHELis, Philip, M.D., Associate Professor of Histology and Demonstrator of Embryolog}', Medico-Chirurgical College, 828 Xorth 5th Street, Philadelphia, Pa. Flint, Joseph Marshall, B.S., A.M., M.D. (Second Vice-Pres. '03-'04), Professor of Surgery, Yale University, 320 Temple Street, Xew Haven, Conn. Frost, Gilman Dubois, A.M., M.D., Professor of Clinical Medicine, Dartmouth Medico'. School, Hanover, N. H. Gage, Simon Henry, B.S. (Ex. Com. '06-'ll), Emeritus Professor of Histologjand Embryology, Cornell University, Ithaca, X. Y. Gage, Mrs. Susanna Phelps, B.Ph., 4 South Avenue, Ithaca, X. Y. Gallaudet, Bern Budd, A.M., M.D., Assistant Professor of Anatomy, Columbia University, Consulting Surgeon Bellevue Hospital, 110 East 16th Street, Xew York, X. Y. Geddes, a. Campbell, M.D., Professor of Anatomy, McGill University, Montreal Canada. Gerrish, Frederick Henry, A.M., M.D., LL.D. (Ex. Com. '93-'95, '97-'99, '02'06, Vice Pres. 'OO-'Ol), Professor of Surgery, Bowdoin College. 675 Congress Street, Portland, Me. Gibson, James A., M.D., Professor of Anatomy, Medical Department, University of Buffalo, 24 High Street, Buffalo, X. Y. Gilman, Philip Kingsworth, B..\., M.D., Philippine General Hospital, Manila, P. I. Goetsch, Emil, Ph.D., M.D., Department of Surgery, Harvard Medical School, Boston, Mass. Greene, Charles W., Ph.D., Professor of Physiologj- and Pharmacology-, University of Missouri, Columbia, Mo. Greenman, Milton J., Ph.B., M.D., Sc.D., Director of the Wistar Institute of Atiaiomy and Biology, S6th Street and Woodland Avenue, Philadelphia, Pa. Guild, St.\cy R., A.B., Instructor in Histologj' and Embryologj-, University of Michigan. 1237 Volland Street, Ann Arbor, Mich. Guyer, Michael F., Ph.D., Professor of Zoology, Uiiiv.M^iix .,f Wisconsin, 138 Prospect Avenue, Madison, Wis. TBK AJ^ATOmCAX. RECORD, VOL. 8, NO. 4 234 AMERICAN ASSOCIATION OF ANATOMISTS Halsted, William Stewart, M.D., Professor of Surgery, Johns Hopkins University, 1201 Eutcnv Place, Baltimore, Md. JTamaxx, Caul A., M.D., (Ex. Com. '02-'04), Professor of Applied Anatomy and Clinical Surgerj', Western Ile.serve University, 416 Osborn Building, Cleveland, Ohio. Hardesty, Irving, A.B., Ph.D., (Ex. Com. '10 and '12-' 15), Professor of Anatomy, Tulane University of Louisiana, Station 20, New Orleans, La. Hare, Earl R., A.B., M.D., Instructor in Surgery, University of Minnesota, 623 Syndicate Building, Minneapolis, Minn. Harper, Eugene Howard, Ph.D., Assistant Professor of Zoology, Northwestern University, 1420 Maple Street, Evanston, III. Harrison, Ross Granville, Ph.D., M.D. (Pres. '12-' 13), Bronson Professor of Comparative Anatomy, Yale University, New Hnven, Conn. Harvey, Basil Coleman Hyatt, A.B., M.B., Associate Professor of Anatomy, University of Chicago, Department of Anatomy , University of Chicago, Chicago, III. Harvey, Richard Warren, M.S., Instructor in Anatomy, Universitj' of California, 23 Panoramic Way, Berkeley, Calif. Hatai, Shinkishi, Ph.D., Associate in Neurologj', Wistar Institute of Anatomy and Biology, Philadelphia, Pa. Hathaway, Joseph H., A.M., M.D., Professor of Anatomy, Anatomical Department, Detroit Medical College, Detroit, Mich. Haynes, Irving Samuel, Ph.B., M.D., Professor of Applied Anatomy and Clinical Surgery, Cornell University INIedical College, 107 West 85th Street, New York, N. Y. Hazen, Charles Morse, A.M., M.D., Professor of Physiology, Medical College of Virginia, Richmond, Bon Air, Va. Heisler, John C, M.D., Professor of Anatomj', Medico-Chirurgical College, 3829 Walnut Street, Philadelphia, Pa. Heldt, Thomas Johanes, Assistant in Anatomy, University of Missouri, Columbia Mo. Herrick, Charles Judson, Ph.D., (Ex. Com. 1913-) Professor of Neurology, University of Chicago, Laboratory of Anatomy , University of Chicago, Chicago, III. Hertzler, Arthur E., M.D., F.A.C.S., Associate in Surgery, University of Kansas, 1004 Rialto Building, Kansas City, Mo. Herzog, Maximilian, M.D., Professor of Pathology and Bacteriology Chicago Veterinary College, 64 West Randolph Street, Chicago, III. Heuer, George Julius, B.S., M.D., Resident-Surgeon, Johns Hopkins Hospital, and Instructor in Surgery, Johns Hopkins Hospital, Baltimore, Md. Heuser, Chester H., A.M., Ph.D., Fellow in Anatomy, Wistar Institute of Anatomy, 36th Street and Woodland Avenue, Philadelphia, Pa. Hewson, Addinell, A.M., M.D., Professor of Anatomy, Philadelphia Polyclinic for Graduates in Medicine, 2120 Spruce Street, Philadelphia, Pa. Hill, Howard, M.D., 1010 Rialto Building, Kansas City, Mo. Hilton, William A., Ph.D., Professor of Zoology, Pomona College, Claremont, Calif. Hodge, C. F., Ph.D., Professor of Biology, Extension Division, Department of Social Biolojjy, Slate University, Eugene, Oregon. MEMBERS 235 HoEVE, HuBERTus H. J., M,D., Meherrin Hospital, Meherrin, Virginia. Hooker, Davenport, M.A., Ph.D., Instructor in Anatomy, Medical Department, Yale University, 1S8 Conner Street, New Haven, Conn. Hopkins, Grant Sherman, Sc.D., D.V.M., Professor of Veterinary Anatomy, Cornell Uuiver.nty, Ithaca, N. Y. Howard, Wm. T., M.D., Professor of General Pathology, Pathological Anatomy and Bacteriology, Western Reserve University, Cleveland, Ohio. HrdliCka, Ales, M.D., Curator of the Division of Physical Anthropology, United States National Museum, Washington, D. C. Huber, G. Carl, M.D. (Second Vice-Pres. 'OO-'Ol, Secretary-Treasurer '02-'13, Pres. '14-) Professor of Histology and Embryology and Director of the Histological Laboratory, University of Michigan, 1330 Hill Street, Ann Arbor, Mich. Huntington, George S., A.M., M.D., D.Sc, LL.D. (Ex. Com. '95-97, '04-'07, Pres. '99-'03), Professor of Anatomy, Columbia University, J^37 West 59th Street, New York, N. Y. Ingalls, N. William, M.D., Associate Professor of Anatomy, Medical College, Western Reserve University, Cleveland, Ohio. Jackson, Clarence M., M.S., M.D., (Ex. Com. '10-'14), Professor and Head of the- Department of Anatomy, University of Minnesota, Institute of Anatomy, Minneapolis, Minn. Jenkins, George B., M.D., Professor of Anatomy, Department of Anatomy, University of Louisville, Louisville, Ky. Johnson, Franklin P., A.M., Assistant Professor of Anatomy, University of Missouri, Columbia, Mo. Johnston, John B., Ph.D., Professor of Comparative Neurology, University of Minnesota, Institute of Anatomy, University of Minnesota, Minneapolis, Mi7in. Jordan, Harvey Ernest, Ph.D., Professor of Histology and Embryology, University of Virginia, University, Va. Kampmeier, Otto Frederick, Ph.D., Department of Anatomy, University of Pittsburgh Medical School, Pittsburgh, Pa. Kappers, Cornelius, Ubbo Ariens, Director of the Central Institute for Brain Research of Holland, Maurilskade 61. Amsterdam, Holland. Keiller, William, L.R.C.P. and F.R.C.S.Ed. (Second Vice-Pres. '98-'99), Professor of Anatomy, Medical Department University of Texas, State Medical College, Galveston, Texas. Kelly, Howard Atwood, A.B., M.D., LL.D., Professor of Gynecology, Johns Hopkins University, I4I8 Eutaw Place, Baltimore, Md. Kerr, Abram T., B.S., M.D., (Ex. Com. 10-14), Professor of Anatomy, Cornell University Medical College, Ithaca, N. Y. Kingsbury, Benjamin F., Ph.D., ^LD., Professor of Histology and Embryology, Cornell I'niversity, 802 University Avenue, Ilhac<i, N. Y. Kingsley, John Sterling, Sc.D., Professor of Zoology, University of Illinois, Urbana, III. King, Helen Dean, .V.B., Ph.D., Assistant Professor of Embryolog.v, Wistar Institute of Anatomy, 36th Street and Woodland Avenue, Philadelphia, Pa. Knower, Henry McE., A.B., Ph.D., (Ex. Com. '11-15), Professor of Anatomy, Medical Department, University of Cincinnati, Station V, Cincinnati, Ohio. 236 AMERICAN ASSOCIATION OF ANATOMISTS KoFoiD. Charles Atwood, Ph.D., Professor of Zoology University of California. Assistant Director San Diego Marine Biological Station, 3616 Etna Street, Berkeley, Calif. KuNTZ, Albert, Ph.D., Department of Anatomy, University of St. Louis, 3911 Castleman Avenue, St. Louis, Mo. KuTCHix, Harriet Lehmann, A.M., Assistant in Biology, University of Montana, 527 Ford Street, Missoula, Mont. Kyes, Prestox, A.M., M.D., Assistant Professor of Experimental Pathology, Department of Pathology, University of Chicago, Chicago, III. Lamb, Daniel Smith, A.]\I., M.D., LL.D., (Secretary-Treasurer '90-'01,Vice-Pres. '02-'03) Pathologist Army Medical Museum, Professor of Anatomy, Howard Universitj', Medical Department, 2114 18th Street N. W., Washington, B.C. Lambert, Adrian V.S., A.B., M.D., Associate Professor of Surgery, Columbia University, 168 East 71st Street, New York, N. Y. La.vd.acre Fr.ancis Leroy, A.B., Professor of Zoologj-, Ohio State L'niversitj', and Professor of Histology and Embryology, Starling Ohio Medical College, 2026 Inka Ave., Columbus, Ohio. Lane, Michael Andrew, B.S., 122 S. California Avenue, Chicago, III. Lee, Thom.^s G., B.S., M.D. (Ex. Com. '08-'10, Vice Pres. '12-'13), Professor of Anatomy, University of Minnesota, Institute of Anatomy, University of Minnesota, Minneapolis, Minn. Lefevre, George, Ph.D., Professor of Zoology, University of Missouri, Columbia, Mo. Leidy, Joseph, Jr., A.M., M.D., 1319 Locust Street, Philadelphia, Pa. Lempe, George Gustave, A.B., M.D., Lecturer on Anatomy, Albany Medical College, 702 Madison avenue, Albany, N. Y. Lewis, Dean D., M.D., Assistant Professor of Surgery, Rush Medical College, People's Gas Building, Chicago, III. Lewis, Frederick T., A.M., M.D., (Vice-Pres. '14), Assistant Professor of Embryology, Harvard Medical School, Boston, .Mass. Lewis, Warren H.armon, B.S., M.D., (Ex.Com. '09-11, '14- ), Professor of Physiological Anatomy, Johns Hopkins University, Medical School, Baltimore, Md. Lillie, Frank Rathay, Ph.D., Professor of Embryology, Chairman of Department of Zoology, University of Chicago; Director Marine Biological Laboratory, Woods Hole, Mass., University of Chicago, Chicago, III. Locy, William A., Ph.D., Sc.D., Professor of Zoology and Director of the Zoological Laboratory, NorthwesternUniversity, 1745 Orrington Averiue, Evanston, 111. LoEB, Hanau Wolf, A.M., M.D., Professor and Director of the Department of the Diseases of the Ear, Nose and Throat, St. Louis University, 537 North Grand Avenue, St. Louis, Mo. Lord, Frederick P., M.D., Professor of Anatomy, Dartmouth Medical School, Hanover, N. H. Lowrey, Lawson Gentry, A.M., Harvard Medical School, Boston, Mass. McCarthy, John George, M.D., Formerly Assistant Professor of Anatomy, McGill University, 112 St. Mark Street, Montreal, Canada. McClure, Charles Freeman Williams, A.AL, Sc.D. (Vice Pres. 'lO-'ll, Ex. Com. '12-'16), Professor of Comparative Anatomy, Princeton University, Princeton, N. J. MEMBERS 237 McCoTTER. RoLLO E., M.D., Professor of Anatomy, Medical Department, Vanderbilt University, Xashville, Tenn. McFarlaxd, Frank Mace, Ph.D., Professor of Histology, Leland Stanford Junior University, Stanford, Calif. McGiLL, CAROLINE, A.M., Ph.D., Pathologist, Murray Hospital, Butte, Montana. McKiBBEN", Paul S., Ph.D., Professor of Anatomy, Department of Anatomy, Western University, London, Canada. McMuRRiCH, James Platfair, A.M., Ph.D. (Ex. Com. '06-'07, Pres. '08-'O9), Professor of Anatomy, University of Toronto, 75 Forest Hill Road, Toronto, Canada. McWhorter, JohS" E., M.D., Worker under George Crocker Research Fund, College of Physicians and Surgeons, Columbia University, 205 West 107th Street, Xew York, X. Y. Mall, Fraxklix P., A.M., M.D., LL.D., D.Sc. (Ex.Com.'00-'05, Pres. '06-'07) Professor of Anatomy, Johns Hopkins Medical School, Baltimore, Md. Maxgum, Charles S., A.B., M.D., Professor of Anatomy, University of Xorth Carolina, Chapel Hill, X. C. Maloxe, Edward Fall, A.B., M.D., Assistant Professor of Anatomy, University of Cincinnati, Station V, Cincinnati, 0. Maxx, Gustave, B.Sc, M.D., Professor of Physiologj', Tulane University, Xew Orleans, La. Mark, Edward Laurexs, Ph.D., LL.D., Hersej- Professor of Anatomy and Director of the Zoological Laboratory, Harvard University, 109 Irving Street, Cambridge, Mass. Martix, Waltox, Ph.B., ^LD., Professor of Clinical Surgerj', Columbia University, 25 West 50lh Street, Xeic York, X. Y. Matas, Rudolph, ^LD., Professor of Surgery, Tulane University, 2255 St. Charlet Avenue, Xeic Orleans, Ln. Maximow, ALEX.iXDER, ^LD., Professor of Histologj' and Embryology at the Imperial Military Academy of Medicine, St. Petersburg, Russia, Botkinskaja 2, St. Petersburg, Russia. Mellus, Edward Lixdox, ^LD., 10 Sewcdl Avenue, Brookline, Mass. Mercer, William F., Ph.D., Professor of Biology, Ohio Universitj'. 200 Eatt State Street, Athens, Ohio. Meyer, Adolf, M.D., LL.D., Professor of Psychiatrj' and Director of the Henry Phipps Psychiatric Clinic, Johns Hopkins Hospital, Baltimore, .Md. Meyer, Arthur W., S.B., M.D., (Ex. Com. '12-'16). Professor of Human Anatomy, Leland Stanford Junior University, Stanford University, Calif. Miller, Adam M., A.^L, Instructor in Anatomy. Columbia University, 4^ West 59th Street, Xew York, X. Y. Miller, William Sxow, M.D. (Vice-Pres. '08-'09), Associate Professor of Anatomy, University of Wisconsin, 415 West Wihon Street. Madison, Wis. MiNOT, Charles Sedgwick, S.B. (Cheni.), S.D., LL.D., D.Sc. (Ex.Com. '99-'a2, '0&-'08, Pres. '(H-'Oo), Professor of Comparative Anatomy and Director of the Anatomical Laboratories, Harvard .Medical School, Boston, Mass. MiXTER, Samlel Jasox, B.S., M.D., Visiting Surgeon Massachusetts General Hospital, 180 Marlboro Street, Boston, .Mass. 238 AMERICAN ASSOCIATION OF ANATOMISTS Moody, Robert Ortex, B.S., M.D., Assistant Professor of Anatomy, University of California, 2836 Garber Street, Berkeley, Calif. MoRGAX, James Dudley, A.B., M.D., Physician, Garfield Hospital, 919 15th Street, McPhcrson Square, Washington, D. C. MoRRiL, Charles V., Ph.D, Instructor in Anatomy, New York University, University and Bellevue Medical College, 538 East 26lh Street, New York, X. y. MuNsox, John P., Ph.D., Head of the Department of Biologj-, Washington State Xormal School, 706 North Anderson Street, Ellensburg, Washington. Murphy, Howard S., D.V.M., Professor of Anatomy and Histology, Ames, la. 519 Welch Avenue, Station A., Ames, la. Myers, Burton D., A.M., M.D., Professor of Anatomy and Secretary of the Indiana Universitj-^ School of Medicine, Indiana University, Bloomington, Ind. Nachtuieb, Henry Francis, B.S., Professor of Animal Biology and Head of the Department, University of Minnesota, 905 S. E. 6th Street, Minneapolis, Minn. Neal, Herbert Vincent, Ph.D., Professor of Zoology, Tufts College, Tufts College, Mass. Newman, Horatio Hackett, Ph.D., Associate Professor of Zoology and Embrj-ology, University of Chicago, Department of Zoology, University of Chicago, Chicago, III. Noble, Harriet Isabel, 262 Putnam Avenue, Brooklyn, N. Y. Parker, George Howard, D.Sc, Professor of Zoology, Harvard University, 16 Berkeley Street, Cambridge, Mass. Paton, Stewart, A.B., M.D., Lecturer in Biology, Princeton University, Princeton, N. J. Patten, William, Ph.D.. Professor of Zoology, Dartmouth College, Hanover, N.H. Paterson, A.m., Professor of Anatomy, University of Liverpool, Liverpool, England. Patterson, John Thomas, Ph.D., Professor and Chairman of the School of Zoology, University of Texas, University Station, Austin, Texas. PiERSOL, George A., M.D., Sc.D. (Vice-Pres. '53-'94, '98-'99, '06-'07, Pres. 'lO-'ll) Professor of Anatomy, University of Pennsylvania, 4724 Chester Avenue, Philadelphia, I' a. PiERSOL, William Hunter, A.B., M.B., Associate Professor of Histology and Embryology, Biolngical Department University of Toronto, Toronto, Canada. PoHLMAN, Augustus G., M.D., Professor of Anatomy, Medical Department, University of St. Louis, St. Louis, Mo. Potter, Peter, M.S., M.D., Oculist and Aurist, Murray Hospital, Butte, Montana, 4II-4IS Ilennessy Building, Butte, Montana. Prentiss, Charles W., Northwestern University Medical School, Chicago, III. Prentiss, II. J., M.D., M.E., Professor of Anatomy, University of Iowa, Iowa City, Iowa. Pri.mrose, Alexander, M.B., C.M.Ed., M.R.C.S.Eng., Associate Professor of Clinical Surgery, University of Toronto, 100 College Street, Toronto, Canada. Pryor, Joseph William, M.D., Professor of Anatomy and Physiology, State College of Kentucky, 261 North Broadway, Lexington, Ky. MEMBERS 239 Radasch, Henry E., M.S., M.D., Assistant Professor of Histology and Embryology, Jeflferson Medical College, Daniel Baugh Institute of Anatomy, 11th and Clinton Streets, Philadelphia, Pa. Ran'son, Stephen- W., M.D., Ph.D., Professor of Anatomy, Northwestern University Medical School, 2431 Dearborn Street, Chicago, III. Reed, Hugh Daxiel, Ph.D., Assistant Professor of Zoology, Cornell University, 108 Brandon Place, Ithaca, N. Y. Reese, Albert Moore, A.B., Ph.D., Professor of Zoologj', West Virginia University, Morgantown, W. Va. Retzer, Robert, M.D., Assistant Professor of Anatcmj', University of Chicago, Department of Anatomy, University of Chicago, Chicago, III. Revell, Daxiel Graisberry, A.B., M.B., Provincial Pathologist, Bacteriologist and Analyst of the Provincial Laboratory, Strathcona, Alberta, Canada. Rhixehart, M.A., M.D., Instructor in Anatomy, Indiana University, 315 X. Walnut Street, Bloomington, Indiana. Rice, Edward Loranus, Ph.D., Professor of Zoology, Ohio Wesleyan University, Delaware, Ohio. RoBiNSox, Arthur, M.D., F.R.C.S. (Edinburg) Professor of Anatomy, University of Edinburg, The University, Edinburgh, Scotland. Ruth, Edward S., M.D., Professor of Anatomy, Southern Methodist University Medical Department, 4i^3 Bryan Street, Dallas, Texas. Sabin, Florence R., B.S., M.D., (Second Vice-Pres. '08-'09), Associate Professor of Anatomy, Johns Hopkins University, Medical Department, Baltimore, Md. S.A.CHS, Ernest, A.B., M.D., Associate in Surgerj^, Washington University Medical School, 1806 Locust Street, St. Louis, Mo. Sampson, John Albertson, A.B., M.D., Professor of Gynecology, Albany Medical College, 180 Washington Avenue, Albany, N. Y. Santee, Harris E., Ph.D., M.D., Professor of Anatomy, Jenner Medical College, and Professor of Neural Anatomy, Chicago College of Medicine and Surgery, 2806 Warren Avenue, Chicago, III. Sc.AMMON, Richard E., Ph.D., Associate Professor of Anatomy, Institute of Anatomy, University of Minnesota, Minneapolis, Minn. Schaefer, Marie Charlotte, M.D., Associate Professor of Biologj-, Histology and Embryology, Medical Department, University of Texas, Galveston, Texas. Schaeffer, Jacob Parsons, A.M., M.D., Ph.D., Professor of Anatomy, Medical Department of the Yale University, 150 York Street, Xcw Haven, Conn. ScHOEMAKER, Daniel M., B.S., M.D., Profcssor of Anatomy, Medical Department, St. Louis University, 1402 South Grand Avenue, Si. Louis, Mo. Schulte, Hermann von W., A.B., M.D., Assistant Professor of Anatomy, Columbia University, 176 West 87th Street, New York, A'. Y. Schmitter, Ferdinand, A.B., M.D., Captain Medical Corps, U. S. Army, Manila, P.I. Scott, Katherine Julia, A.B., Johns Hopkins Medical School, Baltimore, Md. Seeliq, Major G., A.B., M.D., Professor of Surgery, St. Louis University, Humboldt Building, 5S7 Xorth Grand Avenue, St. Louis, Mo. Selling, Lawrf.nce, A.B., M.D., 4S4 Main Street, Portland, Oregon. 240 AMERICAN ASSOCIATION OF ANATOMISTS Senior, Harold D., M.B., F.R.C.S., D.Sc, Professor of Anatomy, New York University, University and Bellevue Hospital Medical College, 338 East 26th Street, Neiv York, N. Y. Sheldon, Ralph Edward, A.M., M.S., Ph.D., Associate Professor of Anatomy, Unirersity of Piltfiburgh Medical School, Grant Boulevard, Pittsburgh, Pa. Shepherd, Francis John, M.D., CM., LL.D. (Second Vice-Pres. '94-'97, Ex. Com. '97-'02), Professor of Anatomy, McGill University, 152 Mansfield Street, Montreal, Canada. Shipley, Paul G., M.D., Assistant in Anatonij*, John Hopkins University, Johns Hopkins Medical School, Baltimore, Md. Shufeldt, R. W., M.D., Major Medical Corps, U. S. A. (Retired)., 5356 Eighteenth Street, N. W., Washington, D. C. Silvester, Charles Frederick, Curator of the Zoological Museum and Assistant in Anatomj', Princeton University, 10 Nassau Hall, Princeton, N. J. Simpson, Sutherland, M.D., D.Sc, F.R.S.E. (Edin.), Professor of Phj'siology, Cornell University, Ithaca, N. Y. SissoN, Septimus, B.S., V.S., Professor of Comparative Anatomy, Ohio State University, 318 West 9th Avenue, Columbus, Ohio. Sludek, Greenfield, M.D. , Clinical Professor of Diseases of the Nose and Throat , Washington University Medical School, 354^ Washington Avenue, St. Louis, Mo. Smith, Charles Dennison, A.M., M.D., Superintendent Maine General Hospital, Professor of Physiology, Medical School of Maine, Maine General Hospital, Portland, Me. Smith, George Milton, A. B., M.D. , Associate in Pathology, Washington University Medical School, 1806 Locust Street, St. Louis, Mo. Smith, Grafton Elliot, M.A., M.D., F.R.S., Professor of Anatomy, University of Manchester, 4 Willow Bank, Fallmofield, Manchester, England. Smith, J. Holmes, M.D., Professor of Anatomy, University of Maryland, Green and Lombard Streets, Baltimore, Md. Smith, Philip Edward, M.S., Department of Anatomy, University of California, Berkeley, Calif. Snow, Perry G., A.B., Professor of Anatomy, School of Medicine, University of Utah, Salt Lake City, Utah. Spitzka, Edward Anthony, M.D., Professor of General Anatomy, and Director of the Daniel Baugh Institute of Anatomy, Jefferson Medical College, 11th and Clinton Streets, Philadelphia, Pa. Steensland, Halhert Severin, B.S., M.D., Professor of Pathology and Bacteriology, and Director of the Pathological Laboratory, College of Medicine, Syracuse University, 309 Orange Street, Syracuse, N. Y. Stiles, Henry Wilson, M.D., Professor of Anatomy, College of Medicine, Syracuse University, Syracuse, N. Y. Stockard, Charles Rupert, M.S., Ph.D., (Secretary-Treasurer '14- ) Professor of Anatomy, Cornell University Medical College, New York, N.Y. Stotsenburg, James M., M.D., Associate in Anatomy, Wistar Institute of Anatomy and Biology, Philadelphia, Pa. Streeter, George L., A.M., M.D., Professor of Anatomy and Director of the Anatomical Laboratory, University of Michigan, 1025 Martin Place, Ann Arbor, Mich. MEMBERS 241 Stromsten, Frank Albert, D.Sc, Assistant Professor of Animal Biology, University of Iowa, 943 Iowa Avenue, Iowa City, Iowa. Strong, Oliver S., A.M., Ph.D., Instructor in Anatomy, Columbia University, 437 West 59th Street, New York, N. Y. Strong, Reuben Myron, Ph.D., Instructor in Zoologj', University of Chicago, Chicago, III. SuDLER, Mervin T., M.D., Ph.D., Professor of Surgery and Associate Dean, School of Medicine, University of Kansas, Rosendale, corner of College and Broad Streets, Kansas. SuNDWALL, John, Ph.D., Professor of Anatomy, University of Kansas, Lawrence, Kansas. Symington, Johnson, M.D., F.R.S., Professor of Anatomy, Queens University, Belfast, Ireland. Swift, Charles H., M.D., Ph.D., Associate in Anatomy, Department of Anatomy, University of Chicago, Chicago, III. Taussig, Frederick Joseph, A.B., M.D., Lecturer in Gynecology, Washington University Medical School, 4^06 Maryland Avenue, St. Louis, Mo. Taylor, Edward W., A.M., M.D., Instructor in Neurology, Harvard Medical School, 457 Marlboro Street, Boston, Mass. Terry, Robert J.wies, A.B., M.D. Professor of Anatomy, Washington University Medical School, St. Louis, Mo. Thompson, Arthur, M.A., M.B., F.R.C.S., Professor of Anatomy, University of Oxford, Department of Human Anatomy, Museum, Oxford, England. Thorkelson, Jacob, M.D., Professor of Anatomy, College of Physiciaiis and Surgeons, Baltimore, Md. Thro, William C, A.M., M.D. , Assistant Professor of Clinical Pathology, Cornell University Medical College, 28th Street and 1st Avenue, New York, .V. 1'. Thyng, Frederick Wilbur, Ph.D., Assistant Professor of Anatomy in the University and Bellevue Hospital Medical College, 26th Street and 1st Avenue, New York, N. Y. Tilney, Frederick, A.B., M.D., Associate in Anatomy, Columbia University, 161 Henry Street, Brooklyn, N. I'. ToBiE, Walter E., M.D., Professor of Anatomy, Medical School of Maine, 5 Dfering Street, Portland, Me. Todd, Thomas Wingate, M.B., Ch.B. (Mane), F.R.C.S. (Eng.) Professor of Anatomy, Medical Department, Western Reserve University, Cleveland, 0. Tr.\cy, Henry C, A.M., Ph.D., Professor of Anatomy, Marquette UniversitjSchool of Medicine, Fourth and Reservoir Street, Milwaukee, Wis. Tuckerman, Frederick, M.D., Ph.D., 16 College Street, Amherst, Mass. TuppER, PaulYoer, M.D., Professor of Applied Anatomy and Operative Surgery. Washington University Medical School, Linmar Building. St. Louis, Mo. Waite, Frederick Clayton, A.M., Ph.D., Professor of Histology and Embryology, Western Reserve University, 1S5S East 9th Street, Cleveland, Ohio. Walker, George, M.D., Instructor in Surgery, Johns Hopkins University, corner Charles and Centre Streets, Baltimore, Md. Wallin, IvanE., Department of Anatomy, University of Louisville, Louisville, Ky. Warren, John, M.D., Assistant Professor of Anatoni\, Harvard Mtdical School, Boston, Mass. 242 AMERICAN ASSOCIATION OF ANATOMISTS Waterstox, David, M. a., M.D., F.R. C.S.Ed., Professor of Anatomy, Utiivcrsity of Lituloti, Kings College, London, W. C, England. We.st. Randolph, A.M., Student, College of Physicians and Surgeons, Columbia University, U West 59th Street, New York, N. Y. Weed, Lewis Hill, A.M., M.D., Cabot Fellow in charge of Laboratory of Surgical Research, Harvard Medical School, Boston, Mass. Weidexreich Franz, M.D., a.o. Professor and Prosector of Anatomy, /S Vogesen Street, Strassburg, i. Els. Germany. Weisse, Faxeuil D., M.D. (Second Vice-Pres. '88-'89), Professor of Anatomy, New York College of Dentistry, 108 East 30th Street,, New York, N. Y. Werber, Ernest I., Ph.D., Northwestern University, Department of Anatomy, Chicago, III. West, Charles Ignatius, I\LD., Associate Professor of Anatomy, Medical Department of Howard University, 92^ M Street N. W., Washington, D. C. Weysse, Arthur Wisslaxd, A.]\L, M.D., Ph.D., Professor of Biology and of Experimental Physiology, Boston University, 688 Boylston Street, Boston, Mass. Whipple, Allen O., B.S., M.D., Instructor in Clinical Surgery, Columbia University, 981 Madison Avenue, Neiv York, jV. Y. Whitehead, Richard Henry, A.B.,M.D., LL.D., Professorof Anatomj', University of Virginia, University P.O., Va. WiEMAN, Harry Lewis, Ph.D., Assistant Professor of Zoolog}- University of Cincinnati, Cincinnati, Ohio. Wilder, Harris Hawthorne, Ph.D., Professor of Zoology, Smith College, Plymouth Inn, Northampton, Mass. Williams, Stephen Riggs, Ph.D., Professor of Zoology, Miami University, 300 East Church Street, Oxford, 0. WiLLARD, Stephen A., Professor of Histology and Embryology, University of Nebraska, Lincoln, N^ehraska. Wilson, J. Gordp:n, M.A., M.B., CM. (Edin.), Professor of Otology, Northwestern University Medical School, 2437 Dearborn Street, Chicago, III. Wilson, James Meredith, Ph.D., M.D., Assistant Professor of Histology and Embryology, St. Louis University, St. Louis, Mo. Wilson, James Thomas, M.B., F.R.S., Challis Professor of Anatomy, University of Sydney, Australia. Wilson, Louis Blanchard, M.D., Director of Laboratories, Mayo Clinic, 830 West College Street, Rochester, Minn. WiNSLOw, Guy Monroe, Ph.D., Instructor in Histology, Tufts Medical College, 145 Woodland Road, Auburndale, Mass. Wituerspoon, Thomas Casey, M.D., 307 Granite Street, Butte, Montana. S(^^ THE DLSTRIBUTIOX OF NERVES TO THE ARTERIES OF THE AR:\I J. (;. KHAMKK WITH A DISCUSSION OF THE CFINKAL AALUE OF RESULTS T. WIXGATE TODD FiDin the Annlomicnl Lahnrntory, W'eslern Reserve University. Cleveland FIVK FKiCRES I. IXTRODUCTIOX Our knowledge concerning the vascular nerves of the body is exceedingly scanty. The standard textbooks contain only scattered and incomplete references to the nerve-supply of bloodvessels. The few isolated papers dealing with the subject are inadequate and do not give clear accounts which can be utilized in clinical practice. For these reasons Mr. Wingate Todd has advised the reinvestigation of the vascular nerves in homo and at his suggestion I have undertaken the dissection of the nervesupply to the arteries in the arm. The importance of the work was first impressed on Mr. Todd by Prof. Ellliot Smith of Manchester, whose description of a vascular nerve to the axillary artery formed the starting jioint of the present restnirch and to which reference will be made later. The following is a brief al)stract of the statements made in various standard textbooks regartling the nerve-supply of the bloodves.sels of the arm: « Hamann, writing in Piersol's Anatomy (1). nuMitioiis (a) the !>upply of fibers to the sulx-iavian artery and its bram-hc-? from the ansa subclavia (p. 13()2). the distrihution of filamrnts (b) to the volar intoros-seous artery from the correspoiKhii^ nerve (p. 1801) and le) to the ulnar artery in the forearm from the palmar eutaneous Itranch of the uhiar nerve i p. 1805). THE AVA.TOMI0M. KEOIRU, VOL. S, S"0. .1 244 J. (J. KRAMER PatiTson ill Cunningluim's Textbook, (2) refers to the brancli supplied by the niusculo-cutaneous nerve to the brachial artery (p. 705) and mentions the first and third groups of filaments in Hamann's description. In (^uain's textbook Syminjjton (3) describes, in addition to those mentioned l)v Hamann, a l)i-anch from the musculo-cutaneous nerve to the l)raciiial artery (p. 75). The irrefi;ularity in precise origin of this nerve is intlicated by the fact tliat it was found b}^ Testut coming from the ])ran('h to the M. brachialis. The textbooks known as Morris' (4) and Gray's (5) Anatomies do not give any further information regarding the vascular nerves of the arm. Hauber's textbook also was consulted without obtaining further information (6). Soulie's descrij^tion in Poirier's treatise (7) mentions the distribution of filaments (a) to tiie ])rachial artery from th{> median nerve (p. 907), (b) to the volar ulnar recurrent artery from the volar interosseous nerve near its origin (p. 908), (c) to the ulnar artery in the forearm from the palmer cutaneous branch of the ulnar nerve (p. 919), and (d) to tiie radial arter\' and vein from the volar terminal branch of the musculocutaneous nerve. He also describes the direct supply of filaments to the subclavian artery and its branches from the inferior cervical ganglion (p. 1094). From the preceding abstract it is clear that the references scattered through the various descriptions are by no means connected or complete. While one expects variations to be found in the origin f)f supply from the sympathetic chain to the subclavian artery, one would like to know whether the same irregularity is to be encountered in the nerve-supply to the other arteries of the arm. The fact that Elliot Smith describes a nerve twig, arising from the lateral antei'ior thoracic nerve, to the axillary artery in a case exhibiting nmltiple anomalies of nerves (8), illustrates the contention that variation is to be noticed among vascular nerves as among nerves to muscle and skin. It is, of course, plain from the outset that the view that the sym])athotic vascular nerves pass along the main l)l()od channels to their distribution on the peripheral vessels, is (juite inaccurate. This view and the evidence for its refutation have already been discussed by Mr. Todd (9), hence I may, without further delay, set down my own observations on the vascular nerves of the arm. DISTRIBUTION OF NERVES TO ARTERIES 245 II. PERSONAL OHSERVATIOXS The dissections were made on six upper limbs. Five of these came from cadavera in the Anatomical Department. One hand and forearm was obtained from Dr. Hamann's operating theatre. This last was dissected within a day or so of amputation in order to confirm the observations made on the cadavera. It may be well to remark at this stage that the dissection of nerves to bloodvessels is much easier on freshly obtained material and also that the embalming of the subject with more than a small percentage of formalin renders difficult the identification of these small nerves from bundles of fascia or connective tissue. The nerves mentioned in this paper were readily identifiable by the naked eye, all doubtful filaments being rejected. As the work progressed it became plain that the recording of every individual nerve filament is impossible and also that there is considerable variation in the exact site of origin of the filament from the nerve and in the situation where it reaches the artery in different arms. That is, the sympathetic fibers to the vessels of the limb are as erratic in their precise origin and distribution as are those in the trunk.. The subclavian and ])roximal part of the axillary arteries receive a nerve-supply directly from the sympathetic chain, between or including the middle and inferior cervical ganglia. In the specimens I have examined, the nerve was moderate in size and reached the artery on its inferior aspect, proximal to the passage of the vessel over the first ril). It accompanied the artery in the interval between the M. scalenus anterior and the bone (fig. 1). The portion of the subclavian artery inunetliately adjacent to its origin was supplied by twigs fron\ the ansa subclavia. I did not find further branches of supply to tlie axillary artery from the lat(M-al anterior cutaneous nerve (see Elliot Smith '9.")). The brachial artery was supplied by a varying number of twigs from the nuisculo-cutaneous nerv(\ In one case, I met witii an exaniiiU* of liigli division of tlic bi-achial arttM'v. which is depicted in figure 2. The n(M-ve-supply in tlie illustration differs in no essential point from tliat of normal brachial arteries. 24«i J. C. KKAMKK CommflA msptfultry MEDIAN NERVE BRACHIAL ARTERY MUSCULO CUTANEOUS NERVE M BICEPS BRACHII cut* RADIAL ARTERY I'in. ! i'inlil siil)cla\ian Mitcry. to sliow iicrx'c-supplN'. in I liis case t lie conipiirativcly larjic fil:tiiiciit arose hy two roots fiom the infciior cervical nanfilioii and the syiiipat liet ic chain iiiiiiiediately :il)ove. Kin. 2 Diagram of nerve-s\ipply to the l)rachial artery. This example showed hijih division of the vessel, hut illustrates as well as a normal specimen the suj)|)ly from the nnisculo-cutaneous nerve. Note that the same nerve supi)Iies an ariditional branch to the proximal part of the radial artery. Ktieh fij^ure represents an individual instance, hut may he taken as a fairly typical illustration of the general i)lan of vascular nerves. The illustrations .are reijiicrd 1(1 one-fourth n(u-mal size. DISTRIBUTION OF NERVES TO ARTERIES 247 The radial artery, as can be seen from figure 3 received a nerve-sup])ly from the superficial ramus of the radial nerve. The dorsal carpal arch and its l)ranches also received twigs from this nerve (fig. ")i. ULNAR NERVE ULNAR ARTERY MEDIAN NERVE RADIAL NERVE (Superficial ramus I RADIAL ARTERY li{^. 3 niafir.un to illustrate the nerve-supply to the radial ami ulnar arteries and to the sui)crficial volar arch. The radial artery, though sometimes receiving a branch from the musculo-cutaneous nerve, obtains branches from thesupcrHcial terminal ramus of the radial nerve. The ulnar nerve supplies its companion artery by twigs from its main trunk and from its palmar cutaneous branch. The complicated supply from median and idnar nerves to the superficial volar arch and digital v(>ssels is also shown. It is to he ronienilHMVil that, as in figiwo 2. the radial artery near its origin may I'ccoivc^ a liranch front the nuisculo-cutaneous nerve. 24S J. t;. KHAMEK The ulnar artery obtained its supjily from the ulnar nerve in the forearm, several twigs arising from tlie iialnuir cutaneous branch (fig. 3). The superficial volar arch and the digital vessels received a complicated sup]ily from the median and ulnar nerves (fig. 3). It will be observed that the distribution of nerves to vessels corresponds fairly exactly with the nerve-supply to the skin of the fingers. Also there is a much more plentiful supply of twigs to the vessels in the more distal parts of the limb. ULNAR NERVE ULNAR ARTERY ULNAR NERVE 'deep ramus' DEEP VOLAR ARCH Fig. i Diugraiii of the branches of th(^ raimis profundus of I he; ulnar nerve to the deep volar arch. The deep volar arch and its branches received their supply from the deep branch of the ulnar nerve (fig. 4). The portion of the dorsal carjjal arch associated with the little and ring fingers was supplied by the dorsal cutaneous branch of the ulnar nerve but the major portion of the arch, as already mentioned, received its supply from the superficial ramus of the radial nerve (fig. 5). I was unsuccessful in identifying nerve fibers to the v'olar interosseous artery and other minor xessels which 1 have not named. DISTRIBUTION OF NERVES TO ARTERIES 249 This, however, does not imply that no nerves are given off to these vessels. Had time permitted the making of a greater number of dissections, filaments undoubtedly would have been ultimately isolated in some instances. RADIAL NERVE (deep ramus RADIAL NERVE (superficial ramus I DORSAL INTER OSSEOUS ARTERY DORSAL CARPAL ARCH r.Z'^' '] n'^T\ '" "'"■ '^'^ ••^"•"'tion ..f bra,u-luvs fn.m the doop terminal and of flu. rad.al an.l ulnar unves to .ho ar.ori.s .>„ tlu- ha.-k of ,h. h^nd. " On the back of the forcvirm sexeral branches were distributed rom the dorsal interosseous nerve (deep ramus of radial nerve) to the dorsal mterosseous artery and its branches (fig o) 2')() T. WIMiATK TODD Alth()Uj»;li tho iiumlKM" of limbs dissocted was not larjj;o. it was sufficient to show that while considerable individual \ariation exists in the precise situation and origin of the nerve-supply of any given vessel, yet the general vascular nervous supply follows a certain well-defined plan. The proximal vessel of the limb (subclavian artery) receixes its nerve-sui)ply directly from the sympathetic chain. The more distal arteries are supi)lied by sympathetic fibers which have traveled to their distribution along special nerve-ti'unks and not along main vessels. These twigs are distributed to the vessels from the nerve-trunks at intervals; the int(M\als jrrowing shorter as the more distal portions of the limb are r(niched, as though a grc^ater wealth of nerves was needed in these parts. Possibh' the diminishing size of the member and consequently the greater need for constant regulation in .size of vessels may be associated with this fact. Again the distribution of nerves to vessels corresponds jDretty closely with the distribution of nerves to the skin and nmsculature of the same area. III. Discrssiox OF KKsri;i"s T. WIN(i.\TK iODD That the nerve-supply of the bloodvessels presents considerable clinical significance has been illustrated by recently recorded ca.ses of cervical rib (e.g., 10). The clinical appearanc(> of the vessels in this disease has' been noted in many cases by xarious writers. Hence it is possible to gi\'e briefly the cliaracteristics. \'ascular symptoms connnence in the fingers and sj)i-ead upwards into the forearm: the radial or ulnar arteries or both may be entirely obliterated. The obliteration may ]iroceed witli considerable rapidity uj) the brachial artery. Occasionally the obliteration readies the sulx-lavian artery, as in the case of ('. F. L., described by Keen (11). The rapidity of the process is illustrated by the following notes of a case in a single woman twentynine years of age, which came under my observation last year. Kxfoliatiou by dry gangnMie of the tij) of the right index finger occurfcd oil .luly \. \$$\2. H_\- the third week in August the pul.se could no loiigei- be \'v\\ ;it tli(> elbow. On Se|)teml)er 10

DLSTKIBUTIOX OF XBK\ES TO ARTERIES 251

the pulse ceased at the level of the insertion of the M. coracobrachiahs. The pulse in the brachial artery became weaker until September 2(), but could still be felt below the posterior fold of the axilla and the pathological change in the arterial wall remained stationary' from that date.

The subclavian artery be^'ond the M. scalenus anterior, if not obliterated, appears frequently dilated. This was so in cases recorded by Keen (11) and Hamann (12).

The hiterference with the circulation in the large vessels is not shared by the smaller arteries in every instance. In Keen's ca.se, (". F. L.. the circulation in the arm generally was unaffected in spite of the fact that no pulse could be detected in any of the large vessels from the subclavian arter}' to the wrist (11). In one ease of mine mentioned recently, pulsation could distinctly be felt in some small arteries, although absent in the larger ones (13). This curious phenomenon has been noted experimentally by Lapinski (14). while the lack of tone in the subclavian and axillary \'essels i-eferred to ab()\e has been shown by Cehanovic to occur- in experimental lesions do). The delay of the pulse so often noted in the disease was found l)v the latter author to be due to the lack of tone in the vessel wall. As regards the early stage of the disease, few exact observations have been made. The clearest statement is that of Osier (l(i). This author found that in one of his cases the radial i)ulse on the two sid^s seemed normal and e(iual during rest. After some exertion the pulse on the affected side (right) became very small, only just perceptilile in fact; the arm becoming congested and cyanotic' As the fallacy of the accepted views on delay in jiulse wave and interference with cii-culation generally has pre\iously been shown \) . it simply i-emains for me to state the view to which Mr. Kranjer and I ha\-e arri\ed by our present study of the anatomical facts.

The subclavian artiM-y. l)(>ing suppliiMl directly by a s\inpathetic twig from the region of the ansa subclavia. is but rarely and secondarily aff(V't(Ml in the disease known as "ctM-vical rib." This twig is iioi caught in the lesion because it lies alongside the

' III a rt'ciMii personal (•omimmiiation. Sir William ( Vsjrr »-t>nfinns this state. iiKMit and assures me thai the faet w.is iioteil l)v main observers in fluscaso.

2o2 T. WIXtiATE TODD

artery which is not locally (lainasoti. The hlaiuents passing to the more distal vessels, especialh' to those of the fingers, become affected in certain instances. For precise information regarding the anatomical facts hearing on this ]ioint. reference must be made to previous papers from this laboratory. From a study of such cases as that of Osier's, already mentioned, the lesion would seem at first to produce stimulation of the vaso-constrictor ner\'es. the pulse becoming temporarih' small and barely j)erceptible. Later, paralysis of the vasoconstrictors is indicated by the dilatation and lack of tone with consequent delay in the pulse shown by Cehanovic's experimental work. This dilatation is sometimes apparent in the axillary and distal subclavian arteries in adA'anced cases. Following on the damage to the nerves, changes occur in the vessel w^all which result in obliteration of the lumen and transformation of the artery into a fibrous cord. This action is selective. For just as some muscles escape, certain vascular areas remain unaffected and. in many cases, carry on the circulation in the limb. The reason for this selective action is not yet apparent. As alreadj- indicated, there is a tendency for large vessels to be affected and for the smaller ones to escape. Doubtless the cause of this will be found in the distribution of the precise fibers to the several vessels. But at j)resent no definite statement can be made. There is certainlya kind of plexus formation throughout the length of the limb, produced by the interchange of \ascular filaments from one large nerve-trunk to another. F^xceedingly significant, when one considers the origin and distribution of \ascular nerves, is the observation of ^^'eir Mitchell (19) that 'trophic' changes are most prone to follow wounds of the nerves to hand or foot (i.e., lowest cord of brachial plexus in which the majority of the vascular nerves exist) and more rarely occur when the injury has involved nerve branches which supply the upper portion of a limb (p. 38). A .striking instance is cited in Case 29 of Weir Mitchell's series (p. 167).

The veins arc also affected in the disease, but they lie outside the scope of the present paper, and will bo considered on some future occasion.

DISTKIBUTIOX OF NERVES TO ARTERIES 253

The practical bearing of the anatomical research at present being prosecuted on the subject of nerve-supply to bloodvessels has been convincingly shown by my erstwhile colleague. Mr. E. D. Telford, in a recent paper in which are to be fcjund details of two cases of neuro-vascular derangement consecjuent on the presence of cervical ribs, which were subjected to operation with the express purpose of arresting a progressive mechanical lesitjn of the vascular nerves (20).

Not only was the condition reUeved by operation but the symptoms produced by the lesion completely disappeared. In Case II, from which we took a short length of the radial artery, the pulse has not reappeared in the main vessels, but in Case I the radial pulse first returned four months after the operation. Only after our experimental work is finished can we state what happened to the artery in order that the pulse might return. The vessel may have been canalized or a new artery may ha\'e grown in the substance of the obliterated vessel, as occurs in the uterus after child-birth.

It is certainly a suggestive fact that the pulse should return four months after operation, when one associates this with the observations of Head and Rivers, who state that the vascular condition of the limb commenced to return to the normal, in their ex])eriment, in 107 days and was cjuite normal in 190 days after section and primary suture of the superficial ranms of the radial and of the musculo-cutaneous nerves at the level of the fossa cubitalis (21).

In conclusion, it is necessary to point out that a study of the neuro-vascular arrangements in the arm has led me entirely to alter my views from those which I held in 101 1. on the causation of the vascular phenomena in 'cervical' rib ca.ses.

For an account of the circumstances leading to this change of view, Dr. AVood Jones' ])ai)or before the l^>yal Society of Medicine, may be consulted (17). My present views on tlie subject lead me to submit an entirely ditYtMvnt descrijition of the methinl of causation of the pulse characteristics front tiiat given some years ago by Habcock (IS).

2.")4 T. \\IN(;A']"K TODD

1\. SIMMAH^

1. The sulx'lavian aiul axillary arteries differ from the other arteries of the arm in receiving a nerve-supply direct from the sympathetic chain.

2. All other arteries in the ui)per limb obtain their nervesupply from sympathetic filaments which have traveled along the spinal nerves and which are distributed to the various blood\essels at irregular intervals.

3. The distal and ]:)eripheral vessels, more particularly those of the hand, receive nerve filaments at more f refluent intervals than do tlie proximal channels.

4. The distribution of nerves to vessels corresponds roughly with the distribution of nerves to nmscles and skin.

5. The fact that the subclavian trunk derives its nerve-supply direct fi-oin the sympathetic chain accounts for its escape from involvement in tli(> lesion associated with the disease known as 'cervical rib.'

(). Paragraph 4 explains the early involvement of the arteries of the hand in the tyjie of ceixical rib lesion in which the vessels are affected.

7. The process of the l)loodvessel affection appears to be (a) stimulation of vasoconstrictor fibers, (b) paralysis of vasoconstrictors (with undisturbed action of vasodilators ?) (c) pathological changes in the vessel wall consecjuent on the lesion of the nerves.

S. Vol the site and cause of the nei"\'e lesion i)i'e\ious ])ai)(M's fi'oni this lal)nrat()rv must he consulted.

DISTHIIUTIOX OF XEHVES TO ARTERIES 2.5o

LITERATIKE CITElJ

(1) IIamaxx, C. a. I'Jll The i)eripher:il nervous system ; in Human Anatomy.

edited by C. A. Piersol; 3d ed.

(2) J'atkkso.v, A. M. I!tl3 The i)eripheral nervous system; in f 'unninKham's

Text-book of Anatomy, 4th Kd.

(3) Syminj^ton 100!) The pcriphcial nervous system; Quain's Anatomy. 11th

Ed., vol. 3 i)t. 2.

(4) Hakdestv, I. 1!)()7 Tlic ncrvou.^ system: .Morris' Human .\natomv. 4th

Ed.

(5) Gray's Anatomy, 19U1, l.jth Ed.

(6) R.\UBER, .\. l'.J()3 Lehrbueh ik'r Anatomie des Menschen; tjth Ed.. Bri. 2.

(7) SouLiK, A. 11304 Xerfs raehidiens; in Poiricr et Charjjy, Traite d'Ana tomie Humaine, 2"'*= Ed., T. 3, fasc. 3.

(8) Elmot .Smith, G. 1895 \u account of some rare nerve and muscle anom alies. Jour. Anat and Physiol., vol. 29, p. So.

(9) ToDU, T. \V. 1913 Imiieations of nerve lesion in certain pathological

conditions of bloodvessel^. Lancet, vol. 1, j). 1371 (lOj Idem. 1913 Bloodvessel changes consequent on nervous lesions. Jour

Xerv. and Ment. Diseases, vol. 40, p. 439. (llj Ki;i:.\. \V. \\'. 1907 Cervical ribs. .\mer. Jour. .\Ied. .Sciences vf»l. 133

]). i7;5.

(12) Hama.v.v, C. a. 1910 A case of cervical ril). Cleveland Med. Jour., vol.

9, p. 453.

(13) Todd, T. \V. 1912 The vasculai- symptoms of cervical rib. Eancet, vol.

2, p. 362. (14j Lai'i.nski 190S (Quoted by v. Bcclitercu : Die Funktionen dcr Xerven centra, vol. 1, p. 547. (15) Ckua.xovic 1897 Der EinHuss der Durclischiicidung des Halssym|>atheti cus auf das Jiussere Ohr. Dissert. St. Petersburgh; (pioted by v. Bech terew (see ref. 14). (IG) OsLKK, SiK William 1910 Certain vasomotor, sensory and muscular phenomena associated with cervical rib. Amer. Jour. Me<l. ."Sciences, vol.

139, 469. (17) WOon JoNKs. 1". 1913 The anatumy of cervical ribs. Proc. Hoy. ."^oc.

.Mid., vol. (i (Clinical .section), p. 95. (IS) H \U((K K, \\ . W . 1905 Cervical ril) with resulting gangrene of the fingers.

.Viiier. .Medicine, vol. 10. |). (illi.

(19) .MrrcHKLL. S. Wkik 1S72 Injuries of Xerves. Lippincott.

(20) Tklkohd, i;. 1). 1913 Two cases of cervical rib with vascular symptoms.

Lancet, vol. 2, p. 11 16. (21 I Ukai), H., A\n HiVKUs. W . 11. H. l«»OS .\ human (>xperiment in nerve division. Ur.-iin. vol. 31, j). 104.

PRELIMINARY NOTICE International Congress of Anatomy

Thf International Coniniitlce for the International Congress of Anatomy has decided that the next meeting shall be held at Amsterdam during -August, 1915. Formal announcement, giving ■ the exact date and other details, \\ ill be issued later and distributed to the members of the American Association of Anatomists. At the last Congress, held in Brussels in 1910, there was a good attendance of American Anatomists, and it is hoped that the American representation will be even larger at Amsterdam.

THE BRAIN OF A BLACK MONKEY, MACACUS

MAURUS: THE RELATR'E PROMINENCE

OF DIFFERENT GYRI

HARRIS E. SANTEE

Fmni JjdhonUorleH of Jenner Medical College and The Chicago College of Medicine

and Surgery

FOUR FKiURES

This brain measures 7 cm. from frontal to occipital pole. Its greatest transverse measurement is (i.2 cm. ; and 4.5 cm. is the height of a cerebral hemisphere. The entire weight equals 114.95 grams, of which the cerel)rum comprises 103.29 grams and the rhombencephalon 11.66 grams. The measurements are approximately proportional to the corresponding dimensions of the human brain; but the relative weight of the cerebrum is nine-tenths of the whole brain. In man the cerebrum constitutes se\'en-eights of the brain.

Upon examining this brain, one familiar with the Innnan brain is impressed with the probable significance of three facts, namely, a remarkable shortening of the frontal region, an abundant fullness of the occipital and hippocampal regions, and a marked prominence of the central gyri. The central sulcus of Rolando is far from central in i)()siti()ii: it divides the convex surface, above and behind the lateral Hssure of Sylvius, very nearly into an anterior third and a posterior two-thirds, a notable variation from the proportions of the human brain.

These variations from the human proportions shouKl be in perfect harmony with the widely ditTerent psychic functions performed by \\\c brains of man and monkey. Moieover. the high development of the motor and sen.sory nerves of the monkey and theii- very strong resemblance to the peripheral nervous

25S II A inns k. saxtee

systoiu of man aiv facts fully as iiiii)rossivo as the iiionkeys (loftciency in psychic apparatus; they speak for the harmony and unity of cn^ition.

Placed alongside the human ))rain and viewcvl in the lifi;ht of cortical localization, a study of the convolutions and sulci of this i)rain from the Macacus maurus possesses somethinfj; more than its own intrinsic interest.

The central sulcus (Rolandi) is well developed but shortened so that it fails to cut the supero-medial border of the hemisphere (figs. 1 and 'A). It possesses two well marked genua and is bounded l)y two jirominent gyri, the anterior and posterior central, which unite around its extremities.

Below the central sulcus and forming a right angle with its inferior extremity, is the great fissure of the convex surface, the lateral fissure of Sylvius. This fissure is unbranched. there being no anterior rami, and is a single fissure from its beginning in the fossa lateralis, near the ()]3tic chiasma, to its posterior termination in the concavity of the supramarginal gyrus. Its extremity, which is not bent upward as in the human brain, appears to open into the superior temporal sulcus; but in reality a submerged part of the supramarginal gyrus separates it from that sulcus. The prominence of the anterior parietal region appears to account both for this crowding downward and straightening of the fissure and for the partial submergence of the supramarginal gyrus. The absence of the anterior rami of the lateral fi.ssure is to be expected in view of the fact that the lateral fissure is formed by the excessive growth and the consecjuent closing in of the walls of \]\c lateral fossa; and, because the frontal wall does not undergo this redundant growth, the ant(M"ior I'ami of the fissure are not produced.

The frontal lobe is deficient antcMior to tlu^ pn^-cMitral sulcus. The anterior (-(Mitral gyrus is $$M'v large and definite. But the suj)erior. middle and inferior frontal gyri are poorly developcnl: they are gi-eatly shortene(l aiileiioi'ly, and tai)er toward the frontal j)ole. 'I'he inferior frontal gyrus has neitlier the triangular nor the orbital portion, seen in the liuiiian brain; it is flexed over the BRAIN OF A BLACK MONKEY 2.59 orbitofrontal sulcus; at the base, it joins the middle frontal gyrus and, at the anterior end, it is continuous with the superior frontal. The middle and superior frontal g3'ri are imperfectly separated and form a triangular field with its apex at the frontal pole. These facts show, first, a large deficiency of psychic brain, as one would anticipate in the monkey; and, second, a relative redundance of motor brain, which is in keeping with the monkey's enormously developed musculature. The parietal lobe is large. It is subdivided by an interrupted postcentral sulcus and a verj^ deep horizontal sulcus. The latter begins as inferior postcentral sulcus and winds over the summit of the angular gyrus where it opens into the occipitoparietal; it separates the supramarginal and angular g^Ti, which are continuous superficially, from the superior parietal gyrus. The superior postcentral sulcus is parallel with the central sulcus as in man, and it intervenes between a well formed posterior central gyrus and a triangular superior parietal gyrus. The parietal gyri are fully as prominent as in man with the exception of the posterior link of the supramarginal gyrus. This is somewhat suppressed and forms a buried gyrus closing the lateral fissure and connecting the sui)ramarginal with the su})eri()r temporal gyrus. The angular gyrus is a large and sharply flexed convolution bent over the angular portion of the superior temporal sulcus, behind which it descends obliquely in front of the simian sulcus (affenspalte) almost to the inferolateral border of the hemisphere; it becomes continuous with both th(^ middle temporal and the lateral occijiital gyri, as in the chimpanzee. In Dwight's chimpanzee the superior postcentral sulcus is longitudinal in direction and di\'ides the superior parietal g\'rus into two sagittal g\'ri, while the horizontal sulcus opens posteriorly into the simian sulcus (affenspalte) instead of into the occipitoparietal sulcus. The prominent development of the whole parietal lobe is entirely consonant with the fact that this lobe contains the receptive and interpreting centers of connnon sensation. The Macacus maurus has opposable thumbs and great t<ies and perfect prehension in all four hands, which are significant THE ANATOMICAL IlECORD, VOL. S, NO. .1 260 HAIJKIS E. SANTEE facts in tho presence of a well (l('V(4()j)e(I ])faeeuneiis and sujKM'ior parietal ^yrus, the cortex containing the stereonogistic center. Alongside the highly developed motor and common sensory gyri, the anterior and posterior central, we should place another reniarkalile fact, namely, the enormous peripheral nerves, which are almost eciual in diameter to the nerves of man, though this monkej' measures from crown to ischial callosities less than 61 cm. (24 in.) and its entire weight is not over one-fifth that of an average adult of 150 pounds. The temporal lobe appears large in its con\ex exposure at first glance, but upon examination this is found to be caused by the crowding of the fusifoi'm gyrus outward into the infero-lateral border of the hemisi)here. The superior temporal gyrus is of large size, especially at its polar end. It presents on its superior surface, well back toward the posterior end, one transverse tem}:)oral gyrus (of Heschlj. The middle and inferior temporal gyri ai'e fused into one and together form a gyrus no larger than the superior. This fused temporal gyrus is di\'ided posteriorly by the inferior occipital sulcus and thus becomes contiiuious with angular and fusiform gyri. The su]Derior temporal sulcus is a remarkable one. It extends without interruption from the temporal pole far up into the ])arietal lobe, showing no sign of separation between the temporal and angular parts. This does not agree with the suj:)i)osed development of this sulcus in man from two short furrows, a temj)()ral and an angular, which later in uterine life run together. The junction with the lateral fissure is only a]:)parent, the submerged link of the supramarginal gyrus really se]mrates them. The slight indentation below the union of the temporal and angular ])arts probably repn^sents the descending branch of the superior temj)oral sulcus as seen in the orang and the chimpanzee. The satisfactory representation of the receptive acustic region, the transverse and superior temporal gyri, should be noted in this brain. Hut no explanation for the bulky anterior end of the superior temporal gyrus is suggested by the facts at hand. If the centers of 'intonations' and 'naming' occupy the anterior twofouilhs of the middle and inferior teni|)oi\'il coiiN-olutions in man, BRAIN OF A BLACK MONKEY 261 we should expect just such suppression of these gyri in the monkey as this brain presents: such intellectual processes as the accurate recognition of tone, pitch and concord appear to have no place in the mentality of the monkey, and Adam only was enjoined to bestow names upon the various objects in his environment; but on the f)ther hand, the reduction in the posterior two-fourths of these gyri, though partly accounted for by the diminutive psychic auditory requirements, is, nevertheless, very strong evidence against the suggestion made by ]\Iills and others, that in man these parts contain the centers of orientation and equilibrium, since the monkey's sense of direction and sense of equilibrium are certainly equal to man's. The occipital lobe is remarkabke for its size and its boundaries; indeed it protrudes so as to appear folded upward over the end of the parietal lobe. The occipitoparietal sulcus which intervenes between them is thus flexed upward ('fig. 3j. The occipitoparietal sulcus is apparently continued downward on the convex surface almost to the inferolateral border of the hemisphere, the arcus occipitoparietalis being entirely absent (fig. 1). This apparent extension, however, is realh' a distinct sulcus characteristic of the simian brain, called the simian sulcus (affenspalte) ; it is separated from the occipitoparietal sulcus by two intcM-locking gyri profundi, which connect the angular gyrus with the superior occipital. The lateral occipital and the inferior occipital sulci are well developed. They run at right angles to the sulcus simialis and lia\e the same arrangement as in tho Macacus siiiicus of Swimmingtou. The lateral occipital sulcus does not reach the sulcus simialis, tiierefore, between them the triangular superior occipital gyrus joins the anterior end of tiie elongated lateral occipital convolution. The inferior occipital sulcus lies below the lateral extremity of the simian sulcus, the two being separated l)v an arcus ()ccij>itotemj)oralis. What api)ears to be a third or inferioi- occipital gyi-us is in iH>ality the gyrus fusilormis crowded out into the* border of the iiemis|)hen\ Th(^ location of the r(M'e|>tive visual center almost wiioUy on the ('on\e\ sui'l'ac(> of the monkey's brain, exce|>ting the lemuer and marnios(M. (>\|)l;iins the gn^it (Expansion of tiiis j>art of the 262 HARRIS E. SANTEE occipital lobe, l^'his monkey possesses binocular \ision and has a highly developed visual apparatus. On the medial surface of the hemisphere the occipitoparietal sulcus fails to join the calcarine fissure and in this respect it appears to agree with all the higher primates below man, though there is a communication between them in Dwight's cliimj)anzee. The ventral end of the occipitoparietal sulcus is bent sharply upward and then continued forward to the sulcus of the corpus callosum, thus partly isolating a small retro-callosal field in which Flechsig has located the center of taste. It would be interesting to know whether this callosal end of th(^ sulcus is a real sulcus limitans for the gustatory cortex. Mewing the medial and tentorial structures in the occipital region (fig. 3), we note first an unbroken calcarine fissure with its posterior end turned upward instead of downward. It runs parallel with the occipitoparietal sulcus. It is bifurcated posteriorly and both branches end in the medial surface. Below the calcarine fissure are the sulcus of the gyrus lingualis and the posterior part of the collateral fissure. Both of these open into the calcarine fissure in the right hemisphere (fig. 3), but neither does so in the left. The collateral fissure is deep and continuous almost to the temporal pole (fig. 4). The sulcus of th(^ gyrus lingualis is very shallow; it strongly resembles the same sulcus in the human brain, but it is not a sulcus limitans of striate cortex in this brain — in fact no line of Gennari is visible in gross section of any part of the occipital lobe. The lateral and inferior occipital sulci wind around the border of the hemisphere into the medial aspect, as shown in figure 3. The cuneus in this brain is not wedge-shaped at all. J^ounded by occipitoparietal sulcus and calcarine fissure, it is of nearly uniform width and is bent forward near its middle into the form of a capital L, reversed in the right hemisphere. It is directly continuous with the gyrus cinguli; this junction is formed in the human brain by the submerged gyrus cunoi, which is here brought to the surface l)y the ex|)aiision and unfolding of the occipital lol)('. The cuneus is not couiiectcMl with \\\o lingual gyrus. BRAIN OF A BLACK MONKEY 263 The gyrus cuneo-lingualis, present in the human brain, is entirely wanting. The Ungual gyrus is very broad. It is di\aded posteriorly b}' the sulcus of the gyrus lingualis. In the right hemisphere it is shortened and bounded posteriorly by the fusion of the collateral fissure with the calcarine fissure; but on the left side, where these fissures do not fuse, it extends backward to the occipital pole and is bent downward so as to form a rounded prominence. Anteriorly the lingual gyrus is directly continuous with the hippocampal gyrus. The hippocampal gyrus is of remarkable size. Its boundaries are very definite. The well developed uncinate (pyraform) region, bounded anteriorly by a definite sulcus rhinalis. is in keeping with the location of the center of smell in this area. The enormous lateral expansion of the hippocampal and lingual gyri almost crowds the fusiform gjTus off the tentorial surface (fig. 4). The subparietal sulcus is very faint (fig. 3, c). Sulcus cinguli is well developed above the corpus callosum where it intervenes between the cingulate and superior frontal gyri ffig. 3, 6) : but the rostral portion (a) is not continuous with this part, a separation common in the human brain. The parolfactory sulci are xery shallow. The posterior and the more definite sulcus (fig. 3,./) forms the anterior boundary of a well do\-oloped gyrus subcallosus. The slender superior frontal gyrus, particularly in its anterior portion, and the very bulky gyrus hippocampi and gyrus lingualis are the notable features of the medial and tentorial surface of this cerebral hemisphere. They emphasize the predominance of archipallium over neopallium. The base of the forebrain presents an orbital surface modeled almost exactly like the human brain, the olfactory and orbital sulci being similar as to situation, length and direction. There is no indication of medial and lateral olfactory gyri seen in a six months human embryo. Three things are esjiecially noticeable in the basal surface. P^irst, the manunillary liody is median and single, as it is in the human embryo and in the adults of many 204 HAKKIS E. SANTEE lower animals. Second, the presence of the gyrus cunei on the surface, connecting a very narrow cuneus with the gyrus cinguli. The third is a fact already mentioned but further emphasized in this view of the cerel:)rum, namely, the massiveness of the hij^pocampal gyrus, especialh' of its jn'raform area, the uncus hippocampi. So, the cortical center of smell, like all other sensory centers, is abundantly represented in this l)rain of the Macacus maurus. SrMMAPvV All parts of this brain which are sensory or motor infunctioti are largely developed, while there is some deficiency in the posterior parietal and inferior temporal regions and remarkal)le defect in the frontal lobe anterior to the precentral sulcus. These deficiencies lie within the association areas of Hechsig, a** was to be anticipated in the beginning. LITKRATIKE CITED 1)^VI<;HT, Thomas 1895 Anatomy of the cliiinpanzce. Boston Soc. Xat. Hist., vol. 5. Mellu.s, E. Lindox 1907-08 Relations of frontal lobe in the monkey. Am. Jour. Anat., vol. 7, No. 2. Campbell, Alfred W. 1905 Histological studies on the lot-alization of (.•erehral function. Cu.\.\i.\(;ham, D. J. 1892 Cunningham Memoirs. MoTT, ScHU.sTEU AND Shekkington. 1911 Motor localization in the brain of the gibbon. Proc. Roy. Soc, July. Retzius, Magnus Gustaf 1906 Ccrcbra simiarum illustrata. MoTT, F. W., AND Kelley, Agnes 1908 Complete survey of cell lamination in cerebral cortex of the lemur. Proc. Roy. Soc.., B., vol. 80. MoTT, Schuster and Halliberton. 1910 Cortical lamination and localization in the brain of the marmoset. Proc. Roy. Soc. B., vol. 82. Schuster, E. H. J. 1911 Cortical cell lamination in cerebral hemisphere of Papio hamadryas. Quar. Jour. Micr. Sc, June. d e 1 g h Fig. 1 Convex suifac<' of tho left cerehra! ln'inisplu'rc of the Macacus niaurus. A,c. sulcus frontalis inferior; l),d. s. frontalis superior, broken into two parts: e, s. praecentralis inferior, eontinuous above with superior frontal sulcus;/, s. praecentralis superior; (/./», s. postcentralis inferior; g. continued as s. horizontalis; 1, s. centralis with genu superius ami genu inferius opening backward; j. 8. postcentralis superior; k, s. occipitoparietalis. which receives the horizontal and on the surface is continuous with the s. siniialis. The latter runs obliquely downward and forwanl toward the infero-lateral border of the hemisphere (AfTenspaltc or s. lunatus) ; /, s. orbitofrontalis; wi. fissura cerebri lateralis tSylvii i ; 71, s. temporalis superior; o, s. temporalis inferi(»r; />, s. occipitalis lateralis; </• *• occipitalis inferior. Fig. ■_' Insula (Ueilii), the frontal, parietal and temporal opercula being cut awa\-. .1, anterior lobule of insula made up of four very ruilimentary gjri breves; b. posterior lobule of insula. gjTUs longus; r, sulcus centralis insulae. 265 FiK. •"'> Medial surface of ri}j;lit cerebral hemisphere of the Macacus niaurus. A, Hiilcu.s roHtialis, or the anterior part of the cinniiiatc sulcus; b, s. cinguli; c, s. subparietali.s; <l, s. occipitoparietalis; c. fissura calcarina at its posterior end where it bifurcates;/, s. parolfactorius posterior; g, s. rhinalis, very well developed; /), a slot leading to the fissura chorioidea, commonly called hipi)ocampal fissure; /, f. collateralis;./, s. saniftalis gyri linnualis. Fij^. 4 Base of forel)rain of the Macacus maurus, the iiiidliraiii being cut through transversely. .1, sulcus olfactorius and a part of the olfactory tract; h, s. orbitalis, ll-shape; r, gyrus fusiformis; tl, s. occipitalis inferior; e, fissura collateralis;/. s. s.igiltalis gyri lingUMlis; g, f. calcarina; //, s. occipitoparietalis, inferior end, •JdCi AN ADDITIONAL CASE OF PANCREATIC BLADDER IN THE DOMESTIC CAT CHARLES E. JOHXSOX From I he Luhdralorij of Comparative Anatomy of Verlebrnles, Uttivers^ity of Minnesota ONE FIGURE In The Anatomical Record for 1911, Dresbach describes the sixth case of pancreatic bladder in the domestic cat that has been recorded in recent years. iNIiller ('04, '10) had previously reported and described five pancreatic bladders from his laboratory, but prior to his accounts only two such anomalies were on record, one by Alayer in 1815, the other bj- (lag;e in 1.S70. It appears from a footnote in Dresbach's article that Miller has more recently found two additional cases of pancreatic bladder, making a total of seven from his laboratory. As suggested by Dr. ]\Iiller CIO), it would ajijiear that either there existed a breed of cats in his locality among which pancreatic bladders were of relatively frequent occurrence, or else there had been careless observation in other laboratories where cats are generally used for dissection. The fact that three of the cases described by hhn occurred in cats from the same farm-house, two of which were full l^rothers, strongly supports the former alternative, and that the structures were inherited. PYom experience hi the laboratory at Minnesota, I am of the opinion that pancreatic bladders are generally rare. The case here reported was found in this lalioratory a number of years ago, 190() or 1007, by Dr. Jolui C. Brown, of St. Paul, then in charge of the courses in vertebrate anatomy, who later kindly left the specinuMi at my (lisi)i)sal. I'$$ll()wing tlio finding of this i)an('reatic l)ladder it was made a practice to caution all students in cat dissection to examine their specimens care 2t)7

L>()S

CHARLES E. JOHNSON

fully for further occurrence of such structures, and in jiractically e\ery instance the cats were also examined l)y Dr. ]3rown and myself. Howin-er. in the five or six years that have elapsed, no additional cases have ai)iieare(l. During- this time approxi

Gallbl...

Pan

PanU

D.diiod.pan. i .♦^'^^n

een

I'ig. 1 Dniwiiifi showiiifi; ])ancrcatic hhuidcr. Tlio liv(>r is roi)resented as seen from the dorsal side when its free edge has been lifted and thrown forward. />.c/ioL, ductus choledochus; D.d«o(/.pfl«., duct from the duoilenal portion of the l)ancrcas; D.sp.pnu., duct from tlie splenic jiortion; Gnll-hl., gall-bladder; Mes., mesentery holding pancreatic bladder ;/'rj7(.,i)ancreas;/'^/ /(./»/., pancreatic bladder: I'nu.hl.tl.. duct (if pancreatir' Iil.i Idcr.

mately four hiuidred cats have \)vvn di.ssected in the laboratory; and th(> probability that pancreatic bladders have escaped our notice. I believe, is exceedingly small. Our cats have come from various parts of the city of Minneapolis but probably a majority from the same section.

PANX'REATIC BLADDER IX THE (AT 2(59

DESCRIPTIOX

The liver, with the stomach and a portion of the duodenum attached, had been removed from the body before it came into my hands. Surrounding tissues had been dissected away and the ducts of the hver and the pancreas exposed. The duodenal division of the pancreas had in large part been cut away, but leaving the portion adjacent to the ampulla of \'ater intact. The whole had been preserved in formalin.

270 CHARLES E. JOHNSON

BIliLKXiUAPHY

I)RF:sn.H. M. liUl An iiistaiicp of jjancroatic bladder in the cat. Anat. liec, vol. 5. G.\GE, S. H. 1879 The ainpuUa of \'ater and the pancreatic ducts in the ilomestic cat. .\nier. Quart. Mic. Journ., vol. 1. Maykr. a. C. ISliJ Blase fiir den Saft dos Pancreas. Arch. f. Anat. u. Phj's., Hd. 1. Miller. W . S. 1904 Three cases of pancreatic bladder occurrinn in the domestic cat. \m. Jour. Anat., vol. 3. 190.5 A pancreatic bladder in the domestic cat. Anat. Anz., Hd. 27. 1910 Pancreatic bladders. Anat. Rec, vol. 4. ON THE RELATIVE GROWTH OF THE ORGANS AND PARTS OF THE EMBRYONIC AND YOUNG DOGFISH (MUSTELUS CANISj HAROLD LESLIE KEARXEY From the Audtovucdl Lahf)riilury, University of }fi.<isouri CONTENTS Iiitrodvictioii -71 Materials and methods -72 Discussion of data 270 Growth of head 275 Growth of systems (skin, skeleton, musculature and viscera as a whole) 277 Growth of individual oi'tians 2S0 a. Brain 2S0 b. Spinal cord 281 c. p:yeballs 281 d. Heart 282 e. Pancreas 283 f . Liver 283 g;. Spleen 285 h. Rectal gland 285 i. Kidne5'S . 286 .1 . Gonads 286 k, Slomacli-intcst itu>s 287 Sununary 288 Literature cited 291 ixruoDrcTioN 111 geiuM'al, l)ut little attention ha.s been jiaid to tiie relative growth of the various organs in fishes. Some scattering ol>servations are included in tlu^ woik of Welcker and Brandt ("03). The most complete data are those of Kellicott ('OS) on the dogfish. These, however, deal onl}' with the relations from birth onward. A knowledge of the earlier embryonic conditions is very desirable in orUm- to trace more completely the growth process and to gi\'e a inon^ (^xtendod basis for comparison with _'71 -/- HAROLD LESLIE KEAHXEV higher \ortohratos. l^'horoforo tho purposo of the present paper is to present and discuss some orij^inal ol)servations on the relative p;rowth of tlie viscera and parts of the embryonic dogfish. Some original data on the ))ostnatal relative growth of the young dogfish are included for comparison with embryonic growth and with postnatal data already- in the literature. The relative growth of the dogfish is briefly compared in a general way with the data in the literature on the relative* growth of higher vertebrates, esi)ecially mammals. l"'his work was done in the Anatomical Laboratory of the Tni\ersity of Missouri under the direction of Dr. C. ]\1. Jackson, to whom I am deeply indebted for invaluable criticism and suggestions. ^L\TERIAL AM) METHODS a. Species examined and description of serial weights and lengths The materials used in this paper consisted of 47 dogfish (Mustelus canis). The dogfish ranged in weight from 0.0084 gram to 1498.8 grams, and in length from 16 muL to 800 nmL Of the embryos; lo weighed less than 1 gram, two between 1 and 2 grams, one between 2 and 3 grams, six between 2 and 4 grams, three between 4 and 5 grams, and two weighed a little more than 5 grams. There is a gap in the series between the o-grani embryos and the fish at or a little before birth, the next larger fish weighing 42.075 grams. Three fish weigh l^etween 40 and 50 grams, two between 50 and (50 grams, one (35 grams, one (api)roximatelyj 72 grams, one 82 grams, one 92 grams, and fom- between 100 and 133 grams. Here again there is a gap, the next larger fish weighing 331 grams. Four fish weigh between 3fK) and 400 grams, and the largest of the series 1498.8 grams. Twenty-one of the dogfish were males, seventeen were females, an<l in nine the sex could not l)e ascertained. Sex was detei'mined by the j)resence or absence of claspers, which structures are present in the male of the species as a partly detached portion of the medial edge of the ventral fin. These dogfish were obtained from the Supj)ly Department of the M.irine Biological l.aboratfiF-A-. A\oods Hole. Massachusetts. RELATIVE GROWTH OF ORGAXS OF DOGFISH 273 h. Preservatiofi of the specimens The larger dogfish f42 grams and upj were preserved in 5 per cent formaHn. Formahn causes in general a swelling of the tissues, which, from data by Jackson '09;. amounted to nearly 13 per cent of the total volume of a human fetus of the fifth month, after three months' immersion in 10 per cent formalin solution. Ff)rmalin is also known to cause unequal expansion of the tissues which fact must be recognized as a source of error in relative weights of a specimen preserved in formalin. It is unlikeh', however, that error from this source would be great enough to influence materially the general conclusions regarding relative growth. The embryonic dogfish were fixed in mercuric chloride and preser\-ed in alcohol. Alcohol causes shrinkage in the tissues, and moreover, being \ery \olatile, would give rise to error from e\'aporation. To offset this, the alcoholic specimens were soaked in water for several days before weighing. The replacement of the alcohol by water in addition to diminishing the error by evaporation, also caused the tissues to swell and regain to a certain extent their former volumes. On occount of the possible changes in the various organs due to the effect of pre.ser\-atives, allowance must be made for a certain amount of unavoidable error. c. Measurements and dissecting methods The f:sh were first washed in water, if formalin-j^reserveti. antl then the total length (tip of nose to tip of taili and trunk length (tip of nose to anus), was carefully noted. Then the gross body weight was taken and the sex noted, after which the organs and parts were dissected out and weighed. Organs not being weighed were kept on a moistened filter paper in a dish with a groundglass co\ei-. First, the head was separated from the body just beiiind the mandibular arch, and weighed. Then the eyeballs were removed, the extra-ocular nuiscles dis.sectetl off, and the optic nerve clipped close to the eyeball. The brain was removed l)y removing the roof of the cranium and cutting the cranial nerves close t conl was cut across postcM'iorly at its junrtion with the brain. The heart was separated anteriorly at tlie junction of tlie conus arteriosus and truncus arteriosus, and ])osteriorly at the junction of the auricle and sinus venosus. Organs having a mesentery were renio\'ed by cutting along the line of attachment of the mesentery to the organ. The stomach and intestines were weighed first with contents and then without contents, the difference l)eing subtracted from the gross liody weight to give the net body w(nght. The contents, howe\(M-. were usually slight in amount. The rectal gland was removed at the line where its duct commenced. The skin includes the skin of the entire body and the adherent subcutaneous tissue. The musculature and the skeleton (minus the few remaining structures, gills, esophagus, etc.) were weighed together, and then the musculature was dissected ofT and the skeleton and ligaments alone weighed. The difference gi\-es the weight of the musculature. The organs and parts weighed were: brain, spinal cord, eyeballs, heart, pancreas, liver, spleen, rectal gland, kidneys, gonads, stomach and intestines, skin, musculature, and skeleton and ligaments. This list is more extensive than that of Kellicott, who observed only the following organs: brain, heart, pancreas, spleen, liver, gonads and rectal gland. Any ai)i)arent abnormalities were noted. In the case of an organ containing cavities, such as the heart, the cavities were thoroughly cleansed before weighing. In the specimens preserved in alcohol the blood in the heart was hardened and sometimes could not l)e thoroughly removed, which accounts for some of the large variations in the weight of this oi-gan. In the smaller fish the weights were recorded to the ten-thousandth of a gram (tenth of a milligram), with the exception of a few instances in wliicii tlic weights wove recorded to the onethousandtli of a gram. In the larger lisli. w(Mghts were recorded to the one-thousandth of a gram, except in the case of total body weights and structures too large to be safely weighed on such delicate balances. As a lule, liowever, in referring to the body weights ill the following paper, the figures are carried only to thr' first decimal place Menth of a gram). The ])erc(Mitages are RELATIVE GROWTH OF ORGANS OF DOGFISH 275 likewise given, unless it is necessary to carry to further decimal places in order to give two significant figures. The organs were first rolled gently on filter paper to remove superfluous moisture and were then placed in a closed dish for weighing to prevent loss by evaporation. DISCUSSION OF DATA To reduce the range of individual variation and thus give a more nearly correct idea of the average relative size of the parts and organs at various periods, figures representing the averages of several individuals of approximately the same body weight are used largely in the discussion instead of considering each individual separately. The individual data are included in the general table at the end of the paper. The group of dogfish whose body weights range between 42 and 82 grams, are considered to represent approximately the conditions found at birth. All these fish appeared to be free living. Kellicott found the average weight of 13 dogfish at birth to be 76.2 grams (maximum 84, minimum 69.5). These fish were born of a single female weighing 8434 grams and this also is the maximum number of young recorded for this fish; so Kellicott says the weights maj^ not represent the precise conditions found at birth. 1. Growth of the head An inspection of the general table of obser\ations shows, as has been repeatedly observed in many different species of animals, that the head is relatively largest early in embryonic life. In the series of fish under discussion, three dogfish embryos with an a\erage body weight of 0.034() gram ha\e an average percentage head weight of 20 per cent. In an a\erage of three slightly lai-ger fish weigliing about 0.0804 gram the average per('entug(^ head weight is 38.9 per cent, in one case reaching 40.5 per cent. The percentage now tlecreases, at first sharply and then more gradually, to 19.5 per cent in an individual with a body weight of 2.() grains. From heiv it rises unexpectedly to 23 THB AN.VTOMK-\l. KECORP, VOL. S, NO. 5 276 HAROLD LESLIE KEARNEY j)er cent iii an average of six specimens with an average body weiglit of 3.7 grams. The average relative weight of l)oth the eyeballs and the brain also rises at this point. The percentage weight of the head now drops to an average of 21 per cent in five individuals having an 'average body weight of 5 grams. Thus on the whole, the relative weight of the head in this series of dogfish becomes less as the fish increases in body weight. In the case of the young dogfish, the table of averages indicates that in general, the percentage weight of the head decreases with age. The variations that exist are small. The percentage weight at about birth is about 17.5 per cent. From this figure, the percentage weight drops rapidly to 12.1 per cent in an average of four individuals with an average body weight of 347 grams. The fluctuations that exist probably represent individual \'ariations. The largest fish weighed 1499 grams and had a percentage head weight of 12.9 per cent. Kellicott's ('08) data do not include the head. From the above series of data it is evident that the percentage weight of the head is highest in the early stages of embryonic growth; that in general it may be said that the head becomes relatively smaller with age. Jackson has found this true in the human embryo, the head reaching its maximum relative size of about 45 per cent of the total body volume during the latter half of the second month. Lowrey finds the same thing true in the pig, the 18 mm. pig having a relative head weight of 29.69 per cent. The relative head weight of the pig thereafter decreases to 6.26 per cent of the total body weight in the adult. The adult human head forms about 6 to 9 per cent of the total body weight. The adult dogfish apparently has a percentage head weight of about 12 per cent. Jackson and Lowrey have observed in the white rat that the head increases in relative size shortly after birth, reaching its maximum (postnatal) in the second week. So far as I have been able to ascertain, this is the only species in wliich this has been observed. RELATIVE GROWTft OF ORGANS OF DOGFISH 277 2. Relative growth of systems a. Skin. Dissection of the skin in small fish embryos is difficult, and the liability of error greater than in some of the other measurements. From the data of the general table, it is evident that the growth of the skin is rather variable. In 20 embryos up to 5 grams, it forms an average of 6.7 per cent of the total body weight (range 5 to 8.7 per cent), with no distinct change according to age. In 13 young dogfish from 43 to 133 grams, the percentage weight of the skin averages 11.3 per cent (7.4-14.5 per cent). Then it drops somewhat gradually to 7.3 per cent in the fish weighing 1499 grams. b. Skeleton {including cartilages and ligaments). The smallest dogfish embryo in which the percentage weight of the skeleton was determined weighed 2.6 grams, and the relative weight of the skeleton was 7.8 per cent. In a heavier individual with a body weight of 3.8 grams, the percentage weight of the skeleton was 4.5. Two individuals averaging 5.1 grams in body weight had an average percentage skeleton weight of 5.5 per cent. The data on the embryos are meager and variable, but seem to indicate that the percentage weight of the skeleton is smaller than in the later stages. In the young dogfish the data on the skeleton are somewhat more complete. In twelve individuals weighing from 42 grams to 133 grams, the average percentage weight of the skeleton was 8.6 per cent, varying from 6.8 per cent to 10.5 per cent. In the five largest fish the average was 9.2 per cent. Individual variations make the general trend uncertain. c. Musrulaturv. Owing to the difficulty of dissecting out the skeleton in such small fish, the musculature and skeleton were weighed together in most of the embryos, and to make the percentages comj)arable, the j^ercentage weight of the musculatiu^ is considered plus the skeleton in nearly all the embryos. Tliis makes the figure higlier than that for the musculature alone, whicli must bo bonio in mind. 278 HAROLD LESLIE IvEARNEY In an average of 20 dogfish embryos, the percentage weight of the musculature and skeleton is about 44 per cent. Allowing 6 per cent for the skeleton would leave 38 per cent of the body weight for musculature. In the young dogfish the musculature is considered apart from the skeleton. In 11 fish ranging in body weight from 42 to 133 grams, the percentage weight of the musculature averages 45.4 per cent. From here it rises rather sharply to 58.1 per cent in an average of 4 fish weighing 347 grams, and then more slowly to 63 per cent in a fish weighing 1499 grams. From the above data it is evident that, in general, the relative weight of the musculature of the dogfish embryo (for the stages observed) is somewhat smaller than at birth. Also that after birth the musculature tends in general to increase in relative weight. Compared with other animals, the dogfish has a very large proportion of musculature. In the white rat, Jackson and Lowrey have found that the musculature forms about 24.4 per cent of the total body at birth. This percentage decreases to 22.8 per cent at one week, and thereafter increases to 45 per cent in the adult rat. For the human newborn, Mtihlmann estimates the percentage weight of the musculature to be 22.4 per cent, increasing to 43.2 per cent at forty-one to fifty years, and thereafter decreasing to 18.6 per cent in old age. In the dogfish the musculature probably increases in percentage weight throughout life. This is due to the fact that the dogfish apparently does not reach a definite adult condition such as that found in manmials. Growth probably continues (according to Kellicott) until the animal dies. In reptiles, Welcker and Brandt find the percentage weight of the musculature to vary from 19 to 57 per cent, in amphibia, from 43 to 54 per cent and in fishes from 49 to 59 per cent. d. Viscera (as a whole). Under this head are included the central nervous system, thoracic and abdominal viscera. The percentage is computed by adding the percentage weights of the individual organs. In an average of 3 dogfish embryos the body weight is 0.34 gram, and the percentage- weight of the viscera 18.9 per cent. RELATIVE GROWTH OF ORGAXS OF DOGFISH 279 This percentage rises to 19.2 per cent in two individuals having an average body weight of 0.67 gram. In the average of the next group of two fish, the body weight is 1.44 grams and the percentage weight of the viscera 17 per cent. The next fish weighs 2.6 grams, and the percentage weight of the viscera is 14 per cent. From here the percentage rises slightly to 14.4 per. cent in five fishes having an average body weight of .3.7 grams. In the average of the next three fish the bod}^ weight is 4.8 grams and the visceral percentage 15.2 per cent. The foregoing figures indicate that the visceral group in the earlier embryos is relatively large, but that it diminishes in relative size as growth progresses. In the earher embryos the high figure is due to the high percentage weight of the central nervous system at this period. As the central nervous system grows relatively smaller, some of the other organs (principally the kidneys) grow relatively larger but do not counterbalance the drop in the nervous system. In the young dogfish the percentage weights of the viscera at about birth are somewhat lower than in the embrj'os ob.served. In a fish weighing 42 grams the relative weight of the viscera is 12 per cent. In the next larger fish the body weight is 47 grams and the relative weight of the viscera is 13.5 per cent. In an average of two larger fish the body weight is 62 grams and the percentage weight of the viscera 11.5 per cent. The next fish weighs 72 grams, of which weight the viscera form 10.6 per cent (the foregoing fish are at or about birth, and in an average of the entire group the percentage weight of the viscera is 12.1 per cent). In the next group of averages, the percentage weight of the viscera in fishes whose body weights range from 92 to 128 grams remains constantly a little over 12 per cent. In an average of the next group of three fish the body weight is 347 grams antl the relative weight of the viscera 14.3 per cent. This figure declines to 9.8 per cent in a fish weighing 1499 grams. From the foregoing it may be seen that the visceral jiercentage is relatively high in the earlier stages of the embryo and that it drops as the general growth of the embryo progresses. At birth the percentage has dropped to about 12.1 per cent. In general, 280 HAROLD LESLIE KEARNEY the percentage apparently increases after birth to a certain point (14.3 per cent in 347-gram fish) and thereafter decreases. Percentage weights of the viscera in the adult dogfish are variable on account of the variability of the liver, in which, as Kellicott has observed, the variability is due to the amount of fat present in the organ. In the white rat, Jackson and Lowrey find the visceral percentage at birth to be 18.05 per cent, which figure increases to a maximum of 21.28 per cent at three weeks and thereafter decreases to 13.3 per cent at one year. This corresponds in general with the visceral growth in the dogfish. Relative growth of individual organs a. Brain. The relative size of the brain is large in the early dogfish embryo, but decreases through embryonic as well as postnatal life. In six embryos having an average body weight of 0.06 gram, the average percentage weight of the brain is 11.4 per cent (range 7.8 to 15.5 per cent). In general, this decreases in the embryos observed at first rapidly and then more slowly to an average of 2.2 per cent in five embr3'os having an average body weight of 4.9 grams. At birth the percentage weight of the brain is between 1 and 2 per cent. Kellicott finds it to be 1.116 per cent, which percentage decreases at first rapidly and then more slowly throughout life. Although there are some fluctuations (the percentage weight of 2,2 per cent recorded for an individual weighing 102 grams is probably either an error or an abnormality), my data (for the weights observed) show likewise a decrease. In a fish weighing 42 grams the percentage weight of the brain is 1.9 per cent; in a fish weighing 1499 grams it is 0.42 per cent. The relative weight of the brain has been more extensively studied than that of any other organ, and in general, has always been found to decrease with increase in body weight. Jackson ('09j finds that in the early human embryo the brain increases in relative weight to a maximum of 20 per cent in the second month, thereafter decreasing to an average of 12.8 per cent in the Rtill-born, and 14.6 per cent in the live-born fetus. Lowrey RELATIVE GROWTH OF ORGANS OF DOGFISH 281 finds the brain in the early pig embryo attaining a maximum relative weight of 9 per cent at 18 mm., thereafter decreasing to about 4 per cent at birth and 0.087 per cent in the adult. Jackson ('13) finds the maximum postnatal relative size of the brain in the white rat to occur, not at birth, but a short time later, reaching 6.7 per cent. b. Spinal cord. An inspection of the table of relative growth of the spinal cord of the embryonic dogfish will show that the spinal cord is relatively large in the early embryo. In a fish weighing 0.1867 gram, the relative weight of the spinal cord is 1.76 per cent. From here it falls at first rapidly and then more slowly to an average of 0.24 per cent in five fish with an average body weight of 3.7 grams. It apparently rises finally to an average of 0.34 per cent in four embryos with an average body weight of 4.8 grams. At some stage between the embryos examined and birth, the relative weight of the cord apparently rises, for in a fish weighing 42 grams it averages 0.50 per cent. As the body weight of the young dogfish increases, the relative weight of the cord fluctuates but on the whole diminishes, and finally drops to 0.17 per cent in a fish weighing 1499 grams. In the human embryo, Jackson ('09) finds that in the fifth week the percentage weight of the cord is 4.85 per cent, and that it diminishes at first rapidly and then more slowly, to about 0.15 per cent at birth. Vierordt gives 0.18 per cent for the relative weight of the cord at birth and 0.06 per cent for the adult. In the pig, Lowrey finds the relative weight of the cord to decrease from 1.87 per cent at 18 mm. to 0.33 per cent at birth and to 0.04 per cent in the adult. In their observations on amphibia and reptiles, Welcker and Brandt find that the cord approaches or exceeds the brain in relative weight. In the dogfish embryo the spinal cord is usually only about one-tenth as large as the brain, while in the adult it is about one-third as large. c. Eyebnlls. In the early dogfish embryo the relative weight of the eyeballs increases rapidly to a maximum of 9.4 per cent in an embryo of 0.06 gram body weight. This percentage drops with irregular variations to an average of 3.6 per cent in four 282 HAROLD LESLIE KEARNEY cn.bryos with budy weight of about 5 grains. At birth the eyeballs form about 2 per cent of the body weight. In the young dogfish, the relative w^eight of the eyeballs drops from about 2 jior cent at birth to 1.1 per cent in four fish averaging 347 grams in body weight. At 1499 grams bod}' weight, the eyeballs form about 0.64 per cent of the body. Throughout postnatal life the eyeballs are as large as the brain and spinal cord combined. In the pig, Lowrey finds that the eyeballs reach a maximum of 1.15 per cent in relative size when the embryo is 86 mm. in length, decreasing to 0.41 per cent at birth and to 0.011 per cent in the adult. In three human fetuses of about the sixth month, Jackson ('09) finds the eyeballs to form 0.45 per cent, 0.40 per cent, and 0.39 per cent of the total body w^eight. According to \'iorordt, the eyeballs form 0.24 per cent of the total human body weight at birth and 0.02 per cent in the adult. Welcker and Brandt give data on percentage weight of the (adult) eyeballs showing the following ranges: fishes, 0.17 per cent to 2.52 per cent; amphibia, 0.56 per cent to 0.85 per cent; reptiles, 0.02 per cent to 0.56 per cent. The eyeballs of the dogfish embryo appear to be unusually large in relative size. They are, however, relatively smaller than in tlie chick. In this animal they reach a maximum of about 25 per cent of the body in the embryo, decreasing to 3 per cent in the newborn, and to 0.3 per cent in the adult. d. Heart. In the two youngest embryos examined, the heart of the dogfish has a percentage weight of 2.4 per cent and 4.3 per cent of the body weight. Earlier stages might show a higher maximum. This high percentage falls rapidly, with irregular variations to 0.21 per cent in four embryos averaging 4.9 grams in body weight. In the dogfish at birth, Kellicott finds the average relative weight of the heart to be 0.11 per cent. In the series presented in this paj)cr (which are of course subject to variation from the small number of observations) the relative weight of the heart at a})out birth averages somewhat higher, being 0.15 per cent. This jKTcentage may be higher than Kellicott's, partly from the RELATIVE GROWTH OF ORGANS OF DOGFISH 283 fact that he did not weigh the complete heart, but only the ventricle and conus arteriosus. Shortly after birth the percentage weight of the heart rises slightly, reaching a maximum of 0.21 per cent in an individual weighing 92 grams. From here it falls, with fluctuations, to 0.2 per cent in a fish weighing 1499 grams. This last figure is probably too high, since Kellicott, in a larger series, finds the percentage weight of the heart in fish of this size to be 0.087 per cent. In the early human embryo, Jackson ('09) has estimated the relative weight of the heart to be more than 5 per cent of the total body. He finds that it decreases rapidly and reaches about 0.7 per cent at birth. In the newborn, Merordt estimates the relative weight of the heart to be 0.76 per cent, and in the adult, 0.46 per cent. Lowrey finds the curve of growth of the embryonic and adult pig heart to be similar to that of the human. e. Pancreas. The pancreas in the embryos weighed was relatively small, forming, in six fish with an average body weight of 0.31 gram, 0.072 per cent of the total body weight. Throughout the series of embryos the pancreas is exceedingh' variable. In three averaging 4.9 grams in body weight the percentage weight of the pancreas is 0.064 per cent. In the young dogfish the pancreas forms at about birth approximately 0.06 per cent of the body weight. In a group of four fish averaging 347 grams in body weight, the percentage weight of the pancreas has increased to 0.14 per cent. Kellicott finds the percentage weight of the pancreas in the dogfish at birth to be 0.08 per cent; this he finds increasing to a maximum of 0.137 per cent in fish weighing about 200 grams, and decreasing thereafter to about 0.075 per cent. In the human embryo, Jackson finds the percentage weight of the pancreas small at first, being 0,032 per cent in a spechnen of the sixth week, while at birth it is 0.145 per cent in the live-born. Merordt gives 0.11 per cent of the total body weight for the pancreas in the newborn, and 0.15 per cent for the adult. Lowrey finds the curve of relative growth of the pancreas in the pig similar to that of the human. 284 HAROLD LESLIE KEARNEY /. Liver. In the earlier stages of embryonic life the Uver of the dogfish is relatively small, forming in four embryos with an average body weight of 0.0752 gram but 2,4 per cent of the total body weight. This percentage rises very suddenly to an average of 5.8 per cent in six fish with an average body weight of 0.3109 gram and then falls very gradually to 4.6 per cent in five embryos with an average body weight of 4.9 grams. The maximum observed was 7.7 per cent. At about birth the average percentage weight of the liver is 4.8 per cent. This is somewhat higher than the figure (3.12 per cent) given by Kellicott. This, of course, may be due to the variations in the smaller number of specimens in this series. .\fter birth the relative weight of the Uver apparently rises to a maximum of 6.9 per cent in four fish with an average body weight of 347 grams. In a fish weighing 1499 grams this has decreased to 5.9 per cent of the total body weight. The relative size of the Uver in the dogfish is variable. KeUicott thinks that this variability is due to the presence of fat in the organ. He finds that in livers of high percentage weight the percentage of fat is also higher, and vice versa. In six of the largest dogfish he measured, Kellicott finds the percentage weight of the liver to be 5.5 per cent, considerably more than in the human adult. In the human embryo, figures by Jackson show that the Uver attains a somewhat higher maximum of percentage weight than in the dogfish, reaching an average of about 7.5 per cent in the second and third months. At birth the percentage is decreasing but is still higher than in the dogfish, being 5.23 per cent in the live-born (Jackson). In the adult human, \lorordt estimates that the liver forms 2.75 per cent of the total body weight. In the liver of the albino rat, Jackson finds the percentage weight to decrease from 4.74 per cent at birth to 3.39 per cent at seven days, thereafter increasing to a maximum of 6.78 per cent at six weeks. This author finds the variability of the liver of the albino rat to be large and irregular. In the pig embryo, Lowrey finds the liver to reach a maximum of 15.88 per cent of the total body weight at 25 mm. Welcker and Brandt give data on the percentage weight of the (adult) liver with RELATIVE GROWTH OF ORGANS OF DOGFISH 285 ranges as follows: of fishes, 1.57 per cent to 3.85 per cent: amphibia, 2.63 per cent to 6.79 per cent; reptiles, 3.33 per cent to 5.78 per cent. g. Spleen. In the dogfish embryo the spleen is relatively .small, and exceedingly variable, the average in the series of twenty-two embryos observed being 0.049 per cent of the total body (range 0.025 to 0.105 per cent). At about birth the average percentage weight of the spleen is 0.098 per cent, somewhat lower than that observed by Kellicott (0.126 per cent). This increases rapidly with some fluctuations to 0.378 per cent at 347 grams body weight and then falls more gradually to 0.185 per cent in a fish weighing 1499 grams. The variabihty of the spleen is striking. In two given individuals of approximately the same body weight the spleen of one may be twice or three times as large as the other. This is in agreement with the great variability of the spleen in higher forms. In the human, Jackson has found the spleen to increase slowly in relative size up to the seventh month; thereafter it increases rapidly, averaging 0.43 per cent in the live-born. Merordt gives 0.25 per cent for the spleen in the adult hmiian. Lowrey finds the prenatal growth curve of the spleen in the pig similar to that of the human. In the white rat, Jackson finds the relative weight at birth to be 0.22 per cent, increasing to a maximum of 0.41 per cent at one week and thereafter decreasing. Welcker and Brandt give data on the relative weight of the (adult) spleen with ranges as follows: of fishes, 0.15 per cent to 0.34 per cent: amphibia, 0.05 per cent to 0.28 per cent; reptiles, 0.04 per cent to 0.11 per cent. h. Rectal gland. The rectal gland, like most of the organs, is relatively heavier in the embryo than after birth. The average of twenty- three embryos gives 0.105 per cent of the body weight. The extreme variations (0.031 to 0.239 per cent) are probably duo largely to difiiculty in dissection. At about birth the relative size of the rectal gland has diminished to an average of 0.032 per cent of the total body weight. Kellicott's figures place this a trifle higher, 0.0398 per cent. The rectal gland appears to increase slightly in relative size after 286 HAROLD LESLIE KEARNEY bii'th, reaching 0.040 per cent in a fish weighing 92 grams, and thereafter decreasing grackially to 0.022 per cent in a fish weighing 1409 grams. KoHirott finds no such increase after birth, the curve of percentage weight falUng throughout hfe. i. Kidneys. In the dogfish embryo the kidneys (mesonephroi) increase from 1.3 per cent to 4.8 per cent at 0.83 grams body weight. At about 5 grams body weight the relative weight of the mesonephroi is 3.8 per cent. At about birth the kidneys form 1.1 per cent of the total body weight. This decreases slowly throughout the series observed and probably throughout life. In a fish weighing 1499 grams the percentage weight of the kidneys is 0.38 per cent. In the human embryo the mesonephroi form only 0.6 per cent of the body at 11 mm., rapidly decreasing thereafter and practically disappearing at about 30 mm. (Jackson). Lowrey finds the mesonephroi of the pig relatively much larger, reaching a maximum relative size of 12 per cent of the body in the early embryo (15 mm.), decreasing thereafter and practically disappearing at about 125 mm. j. Gonads. (1). Female. In the embryonic dogfish the ovaries are relatively small. In an embrj^o weighing 0.412 gram the percentage weight of the ovaries is 0.048 per cent. This increases to a maximum of 0.065 per cent in an embryo weighing 2.6 grams. At about 5 grams body weight the percentage averages 0.057 per cent (0.019-0.092). In the young dogfish the ovaries are relatively much heavier than in the embryo. At about birth the relative weight of the ovaries is 0.4 per cent. At 345 grams body weight this percentage has increased to a maxinmm of 0.81 per cent. At 1499 grams body weight the percentage is 0.28 per cent. None of the ovaries examined contained large yolk-filled ova. ('2). Male. In the dogfish embryo and at birth the testes are relatively of about the same weight as the ovaries. The percentage increases from about 0.4 per cent at birth to a maximum (for the series) of 1.04 per cent at 133 grams body weight. At 352 grams the percentage is 0.74 per cent. Kellicott finds the relative weight of the ovaries of the dogfish to rise after birth to a primary maximum of 0.675 per cent in RELATIVE GROWTH OF ORGANS OF DOGFISH 287 fish of 400 grams. This percentage decreases to 0.43 per cent in fish of about 1700 grams and thereafter tends to rise to a second maximum. In the male he finds the testes to rise from 0.358 per cent at birth to a primary maximum of 0.775 per cent at about 400 grams. This percentage decreases to 0.60 per cent at 900 grams and then rises throughout hfe to a final maxunum ratio of 1.15 per cent: In the human, Jackson finds the sexual gland relatively larger in the embryo than in the later fetal stages and the testis much larger than the ovary at corresponding stages. k. Stomach-intestines. The following data refer to the empty stomach and intestine. In twenty-five dogfish embryos, the stomach and intestines form an average of 2.43 per cent (range 1.5 to 4.5 per cent) of the total body weight. At about birth the percentage weight of the stomach and intestines averages 2.9 per cent. After birth this percentage increases, reaching a maximum of 5,5 per cent at 331 grams body weight and thereafter decreasing probably throughout life, being 2.3 per cent at 1499 grams. This postnatal rise is probably directly due to the change from the embryonic to the free living condition — the response to the demand on the digestive system for the digestion of an entirely different diet. In the human embryo, Jackson finds the stomach and intestines variable. In the newborn, Vierordt estimates that the empty stomach and intestines form 2.1 per cent of the total body weight, and in the adult, 2.06 per cent. In the albino rat. Jackson finds the percentage weight of the empty stomach and intestines in the newborn to be 2.4 per cent, increasing to a maximum of 8 per cent at six weeks and decreasing thereafter to 5 per cent at 1 year. In the pig, Lowrey finds the percentage weight of the stomach and intestines to increase tliroughout the prenatal period, being (empty) about 3.6 per cent at about full term. In the adult they increase to 4.79 jicr cent empty. Welcker and Brandt give data on the percentage weight of the adult intestinal tract showing ranges as follows: of fishes, 2.31 per cent to 5.15 per cent; amphibia, 4.32 per cent to 6.05 per cent: reptiles, 4.84 per cent to 5.()S ]ier cent. 288 HAROLD LESLIE KEARNEY SUMMARY 1. Hie head attains a maximum rolati\'o size of about 40 per cent of the l)ody in the dogfish eml)ryo at 0.09 gram body weight. At birth this has decreased to about 17.5 per cent and continues to fall thereafter, i)robably throughout life. At 1500 grams body weight, it has dropped to nearly 12 per cent. 2. In general the skin rises through embryonic life to about 11.3 per cent at Inrth; thereafter it decreases in relative weight to about 7 per cent of the total body weight. 3. At birth the relative weight of the skeleton has risen to about 8.6 per cent. The maximum (about 10 per cent) occurs shortly after birth, and thereafter the relative weight of the skeleton apparently decreases somewhat. 4. The curve of the relati\'e growth of the musculature and skeleton of the embryo is variable and uncertain. At birth the relative weight of the musculature alone is about 45 per cent of the total body; this increases to nearly 63 per cent at a body weight of 1500 grams. 5. In the embryo the viscera decrease in relative size from over 19 per cent of the body at an early period to about 12 per cent at bu*th. After birth the percentage weight of the viscera attains a maximum of 14.3 per cent (average) at about 350 grams body weight and thereafter decreases to 9.8 per cent at about 1500 grams. The high figures for the early embryos are due chiefly to the relatively large size of the brain. 6. The relative size of the embryonic brain decreases from a maxinmm of about 15 per cent in the early embryo, at first rapidly and then more slowly to about 1.6 per cent at birth. After birth the relative weight of the brain decreases more slowly, but continues to fall throughout the series and probably throughout life. 7. The spinal cord decreases in relative size in the embryo much like the brain, but it is more variable (probably due to error from difficulty in dissection) ; in the early embryo it forms 1.76 per cent. At about birth the percentage weight of the spinal cord is about 0.50 per cent. This figure thereafter de RELATIVE GROWTH OF ORGANS OF DOGFISH 289 creases slowly to about 1.7 per cent. In the embryo the spinal cord is usually only about one-tenth as large as the brain, while in the adult it is about one-third as large. 8. The relative weight of the eyeballs of the embryonic dogfish is variable, but in general it decreases from an early maximum of about 9 per cent. At birth it is about 2 per cent and thereafter it decreases slowly. At 1500 grams body weight, the eyeballs form about 0.(54 per cent of the body. Throughout postnatal life the eyeballs are as large as the brain and spinal cord combined. 9. In general the heart of the dogfish embryo decreases in relative size from a maximum of about 4 per cent, at first rapidly and then more slowly. At birth it is about 0.15 per cent of the total body weight. After birth it rises to nearly 0.20 per cent and then decreases again. The figure (0.20 per cent) found at about 1500 grams is probably too high, since Kellicott in a larger series finds it much lower. 10. The embryonic pancreas remains at about the same average relative size fO. 06-0. 07 per cent) for the stages examined. .\t about birth it forms 0.06 per cent of the body weight, increasing thereafter to a maximum of 0.14 per cent at about 350 grams body weight. 11. In the early embryo the liver rises to a maximum of about 7 per cent of the body. This percentage falls gradually to about 4.8 per cent at birth. Shortly after birth the liver rises and thereafter decreases in relative weight to about 5.9 per cent at 1500 grams. 12. In the embryo the spleen is variable (average 0.049 per cent) but in general it increases in relative weight. At birth the relative weight of the spleen averages about 0.098 per cent of the total body. This figure increases to a maximum of 0.38 per cent at about 350 grams and thereafter decreases. The spleen is exceedingly \ariable in weight. 13. The rehitixe weight of the rectal gland apjiears variable in the embryo, but falls from an axerage of 0.105 per cent to about 0.032 per cent at birth. Shortly after birth the relative weight increases i^lightly and thereafter decreases. 290 HAROLD LESLIE KEARNEY 14. The relative weight of the embryonic kidneys unesonepliroi) increases to a maximum of 4.8 per cent at 1.8 grams body weight, and then shghtly decreases. At birth it has fallen to about 1.1 per cent and continues to decrease thereafter to 0.38 per cent at a body weight of 1500 grams. 15. The testes and ovaries of the embryo are relatively of about the same weight. At birth the relative weights of the testes and ovaries is about 0.40 per cent of the body. The testes increase to a maxinmm of 1 per cent at about 130 grams body weight.. The maximum for the ovaries (0.81 per cent) occurs at about 350 grams and the relative weight thereafter falls to 0.28 per cent at about 1500 grams body weight. 16. The percentage weight of the stomach and intestines on the whole increases in the embryo from a mininmm of 1.5 per cent to about 2.9 per cent at birth. After birth the stomach and intestines increase to a maximum of 5.5 per cent at about 350 grams body weight and thereafter decrease, probably throughout life. 17. Altheugh many minor differences may be observed, on the whole the course of the relative growth of the various organs and parts in the dogfish is strikingly similar to that which has been observed among the higher vertebrates, including mammals and man. RELATIVE GROWTH OF ORGANS OF DOGFISH 291 LITERATURE CITED Jackson, C. M. 1909 On the prenatal growth of the human body and the relative growth of the various organs and parts. Am. Jour. Anat., vol. 9. 1913 Postnatal growth and variability of the body and of the various organs in the albino rat. Am. Jour. Anat., vol. 14. Jackson, C. M., .\nd Lowrey, L. G. 1912 On the relative growth of the component parts (head, trunk and extremities) and systems (skin, skeleton, musculature and viscera) of the albino rat. The Anat. Rec, vol. 6. Kellicott, W. E. 1908 The growth of the brain and viscera in the smooth dogfish. Am. Jour. Anat., vol. 8, no. 4. LowREY, L. O. 1911 Prenatal growth of the pig. Am. Jour. Anat.. vol. 12. MtJHLMANN, M. 1900 Ueber die Ursache des Alters. Wiesbaden. ViERORDT, H. 1906 Anatomische, physiologische und physikalische Daten und Tabellen. 3 Aufl. Jena. VVelcker, H. und Brandt, A. 1903 Gewichtswerte der Korperorgane bei dem Monschen und den Tieren. Archiv fiir .\nthropologie, Bd. 28. TRE AMATOMICAI. RSCOHD, VOL. 8, NO. 5 TABLE 1 General table of individual observations (Miislelus canis) 8BX f KBT BODY WEiaHT IN URAMB 1498.800 LBNOTH IN Ifli. HBAD fO. Total Trunk Net weicbt | Per cent weicht 1 800.0 385.0 ' 193.000 12.88 2 f 360.472 472.0 215.0 43.792 j 12.15 3 m 352.481 495.0 225.0 45.426 12.89 4 m 344.081 , 452.0 210.0 31.266 9.09 5 f 331.512 1 488.0 218.0 47.746 14.40 6 m 133.439 376.0 168.0 19.771 14.82 1 m ; 131.444 382.0 173.0 19.416 14.77 8 m 121.270 315.0 145.0 16.223 13.38 9 m 102.295 339.0 151.0 17.628 17.23 10 f 92.790 343.0 151.0 15.393 16.59 11 m 82.110 320.0 143.0 13.881 16.91 12 m 72.350 321.0 143.0 11.641 16.09 13 f 65.620 306.0 141.0 11.364 17.32 14 f 59.160 280.0 125.0 9.578 16.19 15 m 53.243 283.0 124.0 8.941 16.79 16 m 48.835 279.0 130.0 7.705 15.78 17 f 47.544 273.0 125.0 9.793 20.60 18 m 42.075 253.0 115.0 8.138 19.34 19 f 5.260 113.0 54.0 0.709 13.48 20 f 5.033 113.0 55.0 1.071 21.28 21 f 4.982 111.5 53.0 1.139 22.85 22 f 4.814 104.0 49.0 1.178 24.47 23 m 4.772 112.0 52.5 1.113 23.32 24 m 3.871 106.0 49.5 0.962 24.86 25 f 3.834 102.0 48.5 0.875 22.83 26 m 3.826 100.0 46.0 0.779 20.37 27 f 3.797 98.5 47.0 0.965 25.43 28 f 3.652 101.0 48.0 0.916 25.07 ?9 f 3.516 93.0 46.0 0.695 19.77 30 f 2.606 85.0 43.0 0.507 19.46 31 m 1.744 70.0 36.0 0.301 17.27 32 m 1.139 65.0 32.0 0.321 28.22 33 m 0.826 59.5 28.0 0.238 28.78 34 m 0.740 54.0 26.0 0.189 25.36 35 m 0.525 49.0 24.0 0.166 31 53 36 f 0.412 43.0 21 .0 0.126 30.63 37 m 0,370 45.0 20.1 0.126 34 30 38 m 0.334 45.0 20.0 0.099 28.91 39 313 40.0 21.0 0.095 30.42 40 0.251 37.0 19.0 0.072 28.76 41 0.187 35.5 18.0 0.059 31.66 42 1 ' 0.104 27.0 16.0 0.039 37.60 43 1 „ 0.092 26.0 15.0 0.037 40.50 44 0.061 25.0 14.0 0.023 38.49 46 ? 0.051 24.0 12.5 0.011 21 .02 46 I 1 045 25 13 016 35.51 47 1 ' (MIS 16 () 0.002 1 21.43 292 General table of individual observations (contintied) SEX SKIK SKELETON BEABT NO. Net weight Per cent Net weight Per cent Net weight Per cent in grams weight in grama weigbt in gnunii weight 1 f i09.007 7.27 136.300 9.09 3.003 0.20 2 f 31.041 8.61 32.446 9.00 0.822 0.23 3 m 30.275 8.59 31.186 8.82 0.700 0.20 4 m 22.403 6.51 24.411 7.09 0.503 0.15 5 f 36.211 10.92 40.231 12.14 0.659 0.20 6 m 11.946 8.95 14.000 10.49 0.273 0.20 7 ra 15.054 11.45 14.106 10.73 0.236 0.18 8 m 8.985 7.41 8.315 6.85 0.233 0.19 9 m 12.571 12.29 9.0.59 8.86 0.176 0.17 10 f 13.484 14.53 7.931 8.55 0.194 0.21 11 m 7.246 8.82 6.849 8.34 0.165 0.20 12 m 8.553 11.82 7.636 10.55 0.078 0.11 13 f 8.182 12.47 5.906 9.00 0.124 0.19 14 f 7.375 12.47 0.073 0.12 15 m 5.416 10.17 4.028 7.57 0.058 0.11 16 m 6.443 13.19 2.972 6.09 0.085 0.17 17 f 6.261 13.17 3.498 7.36 0.091 0.19 18 m 3.991 9.49 3.475 8.26 0.076 0.18 19 f 0.368 7.00 0.216 4.10 20 f 0.430 8.55 0.343 6.82 0.019 0.38 21 f 0.308 6.18 0.007 0.14 22 f 0.364 7.55 0.012 0.26 23 m 0.289 6.06 0.010 0.21 24 m 0.322 8.33 0.007 0.19 25 f 0.278 7.25 010 0.26 26 m 0.289 7.56 0.172 4.50 0.006 0.16 27 f 0.274 7.22 0.009 0.23 28 f 0.218 5.98 0.012 0.33 29 f 0.271 7.71 0.015 0.43 30 f 0.227 8.72 0.203 7.80 0.013 0.51 31 m 0.080 4.60 0.012 0.70 32 ra 0.068 6.01 0.003 0.25 33 m 0.0.-)9 7.08 0.002 0.29 34 m 0.0.37 4.99 0.003 0.43 35 in 0.030 5.62 0.001 0.25 36 f 0.023 5.63 37 in 0.025 6.65 0.001 0.19 38 in 021 6.27 0.001 0.29 39 ? 0.003 1.02 40 ? 0.002 0.88 41 ? 42 ? 0.0003 0.29 43 ? 44 ? 0.0003 0.82 45 ? 46 •> 0002 4.27 47 ? 0.000 J 2 38 •_>«):} General table <»/ individual observations (continued) SPINAL COBD Net weight in grams Per cent weight Net weight in grama 1 f 6.298 2 f 2.327 3 m 2.059 4 m 2.012 5 f 3.099 6 m 1.066 7 m 1.676 8 in 1.457 9 m 2.300 10 f 1.228 11 m 1.073 12 m 0.946 13 f 0.930 14 f 0.893 15 m 0.746 16 m 0.988 17 f 0.874 18 m 0.786 19 f 0.066 20 f 0.109 21 f 0.135 22 f 0.093 23 m 0.132 24 in 0.123 25 f 0.117 26 ni 0.074 27 f 0.114 28 f 0.101 29 f 0.062 30 f 0.066 31 III 0.039 32 in 0.057 33 in 0,050 34 in 0.045 3') in 0.040 3(i f 0.036 37 in 028 38 III 0.027 39 •; 0.017 •U) •> o.oas 41 •) 0.020 42 ? 0.011 43 ■; 0.007 44 7 0.009 45 ? 0.004 46 ? O.oas 47 o (X)l 0.42 0.65 0.58 0.58 0.93 1.25 1.28 1.20 2.25 1.32 1.18 1.31 1.42 1.51 1.40 2.02 1.84 1.87 1.25 2.17 2.70 1.94 2.76 3.18 3.04 1.94 3.01 2.78 1.77 2.54 2.25 5 04 6.06 6.06 7.63 8.79 7.68 7.8.5 5.50 3.27 10.44 10.67 7.75 15.13 8.25 11.24 15.48 2.497 0.786 0.812 0.766 1.260 0.505 0.577 0.468 0.333 0.348 0.284 0.316 0.239 0.208 0.213 0.279 0.171 0.209 0.018 0.014 0.017 0.017 0.010 0.008 0.006 0.009 0.011 0.000 0.011 0.004 0.005 0.003 0.003 0.003 0.004 0.002 003 Per cent wsight 0.17 0.22 0.23 22 0.38 0.38 0.44 0.39 0.33 0.38 0.35 0.44 0.36 0.35 0.40 0.57 0.36 0.50 0.36 0.28 0.36 0.36 0.26 0.22 0.16 0.23 0.29 0.24 0.64 0.33 0.59 0.65 0.78 0.76 1.08 0.70 1.77 Net weight in grams 9.541 3.331 4.003 3.003 5.260 2.432 2.486 2.153 2.130 1.236 1.781 1.030 1.548 0.955 1.243 0.874 1.316 1.134 0.116 0.173 0.243 0.186 0.253 0.190 0.200 0.152 0.189 0.185 0.094 0.075 0.059 0.049 0.045 0.038 0.027 0.019 0.020 0.017 0.018 0.018 0.008 0.006 0.007 0.006 0.002 0.0002 Per cent weight 0.64 0.92 1.14 0.87 1.59 1.82 1.89 1.78 2.08 1.33 2.17 1.42 2.36 1.61 2.33 1.79 2.77 2.70 2.21 3.44 4.87 3.86 5.30 4.91 5.21 3.98 4.98 5.06 2.68 2.89 3.39 4.31 5.46 5.12 5.20 4.66 5.30 5.01 5.81 7.2,5 4.02 5.67 7.42 9 38 3.37 2.38 294 General table of individual observations (continued.) BEX MTJ8CULATUHB PANCREAS LIVKB NO. Net weight Per cent Net weight Per cent Net weighl Percent j in grams weight in grams weight in grams 1 weight 1 i f" 939.600 62.96 88.100 5.88 2 1 f 198.554 55.08 0.592 0.16 31.923 8.86 3 m ! 213.814 60.66 0.432 0.12 21.261 1 6.a3 4 m 1 223.589 64.98 0.444 0.13 29.856 8.68 5. f 171.269 51.66 ' 0.481 0.15 12.964 3.91 6 m 77.146 57.81 0.161 0.12 6.216 4.66 7 m 46.990 35.75 0.191 0.15 4.241 3.23 8 m '. 33.505 27.63 1 0.103 0.08 6.413 5.29 9 m 49.327 48.23 0.065 0.06 5.506 5.38 10 f 49.855 53.73 0.058 0.06 5.431 5.85 11 m 40.087 48.82 0.063 0.08 5.239 6.38 12 m 26.436 36.54 0.023 0.03 3.250 4.49 13 . f 31 .905 48.62 0.041 0.06 3.962 6.04 14 f 0.031 0.05 3.115 5.27 15 m 20.483 38.47 1.666 3.13 16 m 28.360 57.87 2.895 5.93 17 f 22.168 46.42 0.038 0.08 2.513 5.29 18 m 0.032 0.08 1.813 4.31 19 f 1.382 26.25 0.211 4.01 20 f 1.830 36.36 0.003 0.05 0.296 5.89 21 f 2.060* 41.35* 0.224 4.49 22 f 2.445* 50.78* 0.003 0.05 0.237 4.93 23 m 2.211* 46.34* 0.004 0.09 0.183 3.84 24 m 1.636* 42.27* 0.003 0.09 0.161 4.15 25 f 1.774* 46.27* 0.003 0.08 0.151 3.93 26 m 1.890* 49.39* 0.001 0.03 0.203 5.31 27 f 1.346* 35.46* 0.003 0.08 0.163 4.29 28 f 1.991* 54.52* 0.003 0.08 0.181 4.94 29 f 0.002 0.06 0.174 4.95 30 f 0.983* 37.72* 0.001 0.03 129 4.93 31 m 0.748* 42.90* 0.001 04 0.106 6 09 32 m 0.472* 41.36* 0.001 0.07 0.05S 5.a5 33 m 0.362* 43.85* 0.001 0.15 0.054 6.49 34 m 0.261* • 35.01* 0.0002 0.03 0.034 4.58 35 m 0.20S* 39.56* O.OOOJ 0.04 027 5 14 36 f 0.191* 46.41* 0.0001 0.02 025 6.12 37 m 0.157* 42.47* 0003 1 0.08 0.019 5.03 38 111 0.152* 44.(>1* 0004 ^ 0.12 0.014 4 04 39 o 0.145* 46 39* 00)2 ' 0.06 0.024 7.73 40 i •) O.llS* 47.09* 0.0001 ' 04 0.016 6.37 41 , -} 0.091* ; 48.. 58* 1 0.0002 11 0.010 5.52 42 •> 0.003 2 40 43 •) 0.002 1.97 44 ? 002 2.47 45 •? 46 9 1 0.001 2 92 47 •> culature i 1 •MU3 >ius skeleton. 295 General table of individual observations {continued) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 IS 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 30 40 41 42 43 44 45 46 47 f f ni 111 f ni 111 m m f m m f f m m f m f f f f in m f 111 f f f f 111 111 m m III f m in •} ? 7 ? ? ? ? ? 1 BPLBBN STOMACH— IMTBSTDrBS RBCTAL OLAND 1 Net weight In grams Per cent weight Net weight In grants Par cent weight Net weight In graniA Per cent weight 2,778 0.19 43.800 2.26 0.341 0.02 1.412 0.39 17.198 4.77 0.162 0.04 1.249 0.36 13.616 3.86 0.108 0.03 1.385 0.40 16.467 4.79 0.153 0.04 1.191 0.36 18.188 5.49 0.478 0.36 5.701 4.27 0.073 0.05 0.386 0.29 5.846 4.45 0.046 0.03 0.173 0.14 3.985 3.29 0.045 0.04 0.107 0.10 2.990 2.92 0.036 0.04 0.103 0.11 2.621 2.82 0.043 0.05 0.116 0.14 2.100 2.67 0.082 0.11 2.034 2.81 0.010 0.01 0.079 0.12 0.877 1.34 0.027 0.04 0.053 0.09 1.635 2.76 0.014 0.02 0.037 0.07 1 .297 2.44 0.030 0.06 0.053 0.11 2.073 4.24 0.025 0.05 0.056 0.12 1.749 3.66 0.023 0.05 0.034 O.OS 1.468 3.49 0.015 0.04 0.146 2.78 0.002 0.04 0.005 0.11 0.001 1.81 0.006 0.12 0.002 0.04 0.083 1.66 0.005. 0.10 0.002 0.01 0.173 3.60 0.005 0.10 0.002 0.05 0.215 4.50 0.005 0.11 0.001 0.03 0.110 2.59 0.004 0.10 0.001 0.03 0.152 3.96 0.005 0.13 0.001 0.03 0.083 2.17 0.001 0.03 0.001 0.03 0.080 2.34 0.005 0.14 0.001 0.03 0.086 2.36 0.005 0.14 0.001 0.03 0.065 1.85 0.002 0.06 0.002 0.08 0.056 2.16 0.001 0.05 0.001 0.06 0.041 2.36 0.001 0.04 0.001 0.07 0.028 2.42 0.002 0.13 0.0004 0.05 0.015 1.85 0.001 0.13 0.001 O.OS 0.016 2.17 0.001 0.00 0.0002 0.04 0.009 1.68 0.001 0.15 0.0002 0.05 0.006 1.50 0.0002 0.05 0.0002 0.05 0.008 2.22 (1002 0.05 0.0002 0.06 0.007 1.93 0.0001 0.03 0002 0.06 0.006 1.98 0.001 0.22 0.0001 0.04 0.005 2.07 0.001 0.24 O.OMl 0.05 0.004 3.75 0.003 2.73 0.001 2.30 0001 0.16 296 General table of individual observations (continued) SEX EIDNETB GONADB NO. Net weight In grams Per cent weight Net weignt In grams Percent weignt 1 f 5.661 0.38 4.228 0.28 2 f 2.901 j 0.80 3.096 1 0.86 3 m 2.556 ! 0.73 2.621 0.74 4 5 m f 2.556 2.702 0.74 0.82 2.046 2.559 0.59 0.77 6 m 1.188 0.89 1.389 1.04 7 m 1.094 0.83 0.696 53 8 m 0.983 0.80 0.503 0.41 9 m 0.996 0.97 0.524 0.51 10 f 0.888 0.96 0.294 0.32 11 m 0.714 0.87 0.234 0.28 12 m 0.560 0.77 0.363 0.50 13 f 0.981 1.49 0.274 0.42 14 f 0.593 1.00 0.197 0.33 15 m 0.440 0.83 0.128 0.24 16 m 0.693 1.42 0.224 0.46 17 f 0.773 1.61 0.201 0.42 18 m 0.447 1.07 O.lol 0.36 19 f 0.157 2.97 0.001 0.02 20 f 0.167 3.32 0.003 0.06 21 f 0.243 4.88 • 0.005 0.09 22 f 0.200 4.16 0.003 0.05 23 m 0.181 3.80 0.002 0.05 24 m 0.162 4.19 0.003 0.08 25 f 0.136 3.56 0.002 0.05 26 m 0.119 3.12 0.002 0.05 27 f 0.142 3.74 0.002 0.04 28 f 0.135 3.70 0.002 06 29 f 0.095 2.71 0.002 0.06 30 f 0.091 3.50 0.002 07 31 m 0.064 3.68 0.001 0.07 32 m 0.055 4.80 oo;m 0.04 33 m 0.038 4.59 0.001 a*^ 34 m 0.014 1.90 0002 0.03 35 m 0.013 2.49 0004 O.OS 36 f 0.009 2.23 0.0002 05 37 m 0.012 3.11 0.0002 0.05 38 ni 0.005 1.44 0.0002 0.06 39 ? 0.010 3.26 0.0004 13 40 ? 004 1.67 0.0004 0.16 41 42 ? ? 0.004 1.92 0.0001 0.05 43 ? 44 45 ? ? O.OOl l.Sl 46 47 ? 1 ? 0.001 1 1.35 2'.>7 PHILADELPHIA ACADExMY OF SURGERY The .Samuel D. Gross Prize, Fifteen Hundred Dollars. Essays will be received in competition for the prize until January Ist, 1915. The conditions annexed by the testator are that the prize "shall be awarded every five years to the writer of the best original essay, not exceeding one hundred and fifty printed pages, octavo, in length, illustrative of some subject in Surgical Pathology or Surgical Practice, founded upon original investigations, the candidates for the prize to be American citizens." It is expressly stipulated that the competitor who receives the prize, shall publish his essay in book form, and that he shall deposit one copy of the work in the Samuel D. Gross Library of the Philadelphia Academy of Surgery, and that on the title page, it shall be stated that to the essay was awarded the Samuel D. Gross Prize of the Philadelphia Academy of Surgery. The essays, which must be written by a single author in the English language, should be sent to the "Trustees of the Samuel D. Gross Prize of the Philadelphia Academy of Surgfcry, care of the College of Physicians, 19 S. 22nd St., Philadelphia," on or before January 1, 1915. Each essay must be typewritten, distinguished by a motto, and accompanied by a sealed envelope bearing the same motto, containing the name and address of the writer. No envelope will be opened except that which accompanies the successful essay. The Committee will return the unsuccessful essays if reclaimed by their respective writers, or their agents, within one year. The Committee reserves the right to make no award if the essays submitted are not considered worthy of the prize. WILLIAM J. TAYLOR, M.D. RICHARD H. HARTE, M.D. JOHN H. GIBBON, M.D., Trustees. Philadelphia, 1914 THE ERUPTION AND DECAY OF THE PERMANENT TEETH PRELIlvnNARY REPORT ROBERT BENNETT BEAN From (he Annlomical Laboratory, Tulane University Data: 2221 school children 630 Filipino male (five to thirty years) 776 146 Filipino female (five to thirty years) 322 German male 628 306 German female 407 American male (five to eighteen years) 817 410 American female (five to eighteen years) 2221 Tota l GENERAL RESULTS Eruption of the teeth The Filipinos are from one to four years earUer than the Germans and Americans in the eruption of the permanent teeth, and the Americans are slightly carher than the Germans. The females are more precocious than the males in the three groups, but this difference is very shght among the Filipinos, and a little less among the Germans than among the -Americans. The Filipinos are more homogeneous sexually (there is less difference between the sexes) than the .Vmericans, who are more heterogeneous than the Germans. The lower teeth erupt before the upper, except that the upper premolars erupt l)efore the lower. The permanent teeth erupt 299 300 ROBERT BENNETT BEAN at three periods, about the ages of 7, 10 and 18 years, in connection with the eruption of the three sets of molars, and the first two periods alternate with periods of rapid growth in stature. Individual teeth The teeth erupt in the following order: 1. Lower first molars 9. Lower median premolars 2. Lower median incisors 10. Upper lateral premolars 3. Upper first molars U. Upper canines 4. Upper median incisors 12. Lower lateral premolars 5. Lower lateral incisors 13. Lower second molars 6. Upper lateral incisors 14. Upper second molars 7. Upper median premolars 15. Lower third molars 8. Lower canines ^ 16. Upper third molars This order is followed by the Germans and Americans, and also by the Filipinos except that among the Filipinos the canines erupt earlier than the premolars and upper lateral incisors, and the canines erupt from two to four years earlier in the Filipinos than in the Germans and .Ajnericans. The law of alternation in development A law of alternation in development has been deduced, based upon the alternation of periods of acceleration and retardation in the growth of the long bones (stature), upon the periods of acceleration and retardation in the development of the permanent teeth, as well as from a general knowledge of development, especially from the researches of Donaldson, Jackson and others. This law may be formulated somewhat as follows: There are one or more periods of acceleration alternating with periods of retardation in the development of the structures of the body. The periods of acceleration in the development of one structure are synchronous with the periods of retardation in the development of another. The various structural parts, or organs, of the body do not develop synchronously, nor with equal rapidity during the same periods of time, but first one then another develops. Thus the ERUPTION AXD DECAY OF TEETH 301 period of the fi^^.t six months after birth is one of rapid growth in length which is followed by the eruption of the temporary teeth, all of which are through the gums by the end of the third year, after which there is a period of rest. Following this there is another period of rapid growth in length (stature), subsequent to which the permanent teeth begin to erupt, after which the growth of the body is again accelerated, to be followed by a second rapid eruption of the permanent teeth, and then another rapid gi*owtli of the body which is succeeded by puberty. The development of the organs in the embr^^o and the fetus, as well as after birth may be given to illustrate the law of alternation. The early development of the heart precedes that of the lungs, the late development of the Uver precedes that of the stomach and intestine, and the development of the brain and head precedes that of the trunk and extremities. The law is not only applicable to normal development but also seems to apply to abnormal development through a process of compensation. If one structure is unusually precocious in the periods of acceleration in development, its complementary structure will be backward in the periods of acceleration, and vice versa. Thus the upper canines are precocious in the Filipino boys, and the upper lateral incisors are backward, and the upper lateral incisors are precocious in the Fihpino girls and the upper canines are backward. Other examples could be cited but these suffice to illustrate the law. Decay of the teeth The temporary teeth of the Americans are worse than those of the Filipinos which are worse than those of the Germans. The permanent teeth of the Americans' are worse than those of the Germans which are worse than those of the Filipinos. The girls have worse teeth than the boys in all the groups. 302 ROBERT BENNETT BEAN Morphologic form and teeth Those indiv'iduals with long faces, heads and noses, and large occipital circumferences of the head have worse teeth than those individuals with broad heads, faces and noses and large parietal circumferences of the head, and the teeth of the former develop earlier than the teeth of the latter. The long head-face-nose forms with the large occipital region of the head have been called Hyper-onto-morphs by me, and the broad head-face-nose forms with the large parietal region of the head have been called Hypo-onto-morphs. The relative number of Hyper-onto-morphs is greatest among the .Vmericans, least among the Filipinos, and nearly as great among the Germans as among the Americans. Hypo-morphism decreases with age, and Hyper-morphism increases, so that whereas among the Filipinos there are 15.2 Hypos to 1 Hyper between the ages of five and sixteen, there are only 3.8 Hypos to 1 Hyper from 16 to 30 years of age. Hypo-morphism is a condition of less maturity than Hyper-morphism. Apparently the Filipinos mature more slowly than the Americans and Germans in morphologic form, although they mature earlier in stature and in the eruption of their permanent teeth, which, again, may be only another expression of compensation in the law of alternation in development. OSTEOLOGY REDIVIVUS: A CRITICISM ARTHUR WILLIAM MEYER The Dirision of Anatomy of the Department of Medicine, Stanford Uniier.^ily It has been a time-honored custom to introduce the student of medicine to anatomy by a course in osteology. Since this course was, as a rule, prehminary to dissection, the student obtained his first impressions of human anatomy from it. While not underestimating the influence of the individual teacher in the present , the personal element in the past, no doubt, played a far more important part in the presentation of this or of any other laboratory subject, because the laboratory equipment was generally inadequate or more often lacking altogether. Not an extensive equipment was needed for osteology, to be sure, but as long as the student had to go to a laboratory to study bones literally chained to the desk or where he might look at a skeleton through glass doors, none but the most persevering and resolute could be expected to take more than a compulsory or perfmictory interest in the subject, unless, as was fortunately often the case, stimulated by the personality of an inspiring and enthusiastic teacher. The exact nature of the work usually given is known better to others than to myself, but generally the student merely studied a book or manual containing a bare, even if a detailed, description of individual bones; and the instructor failed to present the much broader and far more interesting aspects and relations of the subject. Under such circumstances bones were dry indeed and it is not at all siu-prising that these conditions originated and perpetuated the oft-used phrase di-y as bones." It is to be regretted that the present teaching of osteology has not been wholly liberated from the onus of this phrase or from the burden of such conditions. If the study of osteology must be reduced to the mere memorizing and recognition of the external features of hones, then there is no escape from making it more 304 ARTHUR WaLLIAM MEYER than a more task of memory — a sort of mental gjumastics — the burden of which is not hghtened appreciably by lectures and recitations in which the lecturer recited a textbook description on one day and the student in tm-n recites it the next. The use of cues, or of mnemonic crutches on the part of the student, or of simimaries on the part of the lecturer, stating that there are "eleven points of interest on the inferior surface of the temporal bone" or that there are so many angles or processes on this or that bone, can really not mitigate matters much even if the applicant for licensure passes his examination with a score of one hundred. The latter is an accomplishment wholly within the power of any highschool boy with a good memory, who has never been in an anatomical laboratory. Neither can drawing bones or modelling them in clay, however valuable as adjuncts, do much to relieve such drudgery. Not that the reproduction in clay of the main features of bones is not worth while and may not impress the form of bones more lastingly upon the mind, but until sufficient control over the mechanics of modelling has been acquired the student's attention is occupied largely with the details of a process rather than with the real end to be attained. ^Moreover, most students manifestly cannot obtain sufficient mastery over the art of modelling in the time at their disposal, to be able to reproduce the relief of bones with the necessary detail. Hence only the most obvious things are emphasized while the less obvious and the less evident but often the more significant features, are likely to be overlooked. Besides, the end in view manifestly is not the production of a fine model but the acquisition of knowledge and an acquaintance with the subject. It is the same with drawing. Both must ever remain mere means to an end. One or both may be indispensable for some or even for the majority of students but in any case they can be of value only by sthnulating and assisting in training powers of observation and by increasing interest in and knowledge of a subject. To be sure,* the employment of these aids may also enrich the student's armamentarium and make him a })etter craftsman, but the l)etter-trained, the maturer and the more capable he is, the less will he rely upon such accessories for obtaining a grasp of any subject, however difficult. OSTEOLOGY REDIVIVUS 305 Hence it seems to me that the true attitude on the part of both teacher and student, to these or any other aids, however valuable, during years devoted primarily to dicipline, should be an entirely volitional and not an obligatory one, for this is the time when the mature student should be thrown upon his own responsibility and his creative powers given free play. A plastic and capable mind, I presume, never does end its days of seK- training, but any mature student who prefers to dispense with all prescribed aids, or with his teacher for that matter, should be permitted to do so. Training of the mind must naturally continue but personal guidance should become less and less necessary. This shifts the burden from the instructor's to the student's shoulders and holds women and men preparing for a serious profession, responsible for the consequences of their own acts. And surely young women and young men who have had three or four or more years of college training after passing the highschool, cannot be subjected to pedagogical absolutism without inviting and engendering antagonism, or very seriously thwarting initiative and destroying their interest in a subject. Hence it seems to me that entire freedom — and responsibility should characterize the work of mature students in medical as in graduate work. Freedom on the part of the student to adopt whatever means he prefers in the attainment of a definite or of a given end, is absolutely essential and the attainment of that end should be made the chief rule by which he is measured. But freedom on the part of the instructor from pedagogical routine of all sorts and freedom from responsibility for failure on the part of every student to reach a certain specified end at a certain definite time is just as essential. For however disastrous laissez faire may have been and still is, in the industrial world or in the kindergarten, it is a sine quo nofi for the spontaneous intellectual development of women and men. We may compel scholar.'^hip in boys and girls but the intellects and capacities of women and men who have chosen their life's work. I take it. can be truly developed only where supervision is reduced to a minimum and where in the familiar words of I'lrich von Hutten. "der Wind der Freiheit weht." 306 ARTHUR WILLIAM MEYER If graduate work can prosper only where and when students are freed from pestiferous intermeddhng and allowed or made to assume responsibility for themselves, then neither can medical education be at its best in a highschool atmosphere. And surely in the profession of medicine, we are dealing with women and men and not with girls and boys. It is true that some educated Enghshmen still speak of boys of sixteen who are attending this or that preparatory school, beginning the study of medicine, but that is fast becoming impossible in this country. Girls and boys cannot study medicine to advantage nor prosper in an atmosphere congenial to, and indispensible for the best development of maturer minds. I am well aware that the granting and the assumption of freedom implies a risk; perhaps too great a risk for some medical students, but that is unavoidable. It is a wellknown axiom that we cannot have freedom without risks and that if we are unwilling to take the risk we cannot have freedom or the golden fruit which it alone matures. If the student who is beginning the study of osteology is given free access to abundant material and enabled to see that the many details which he must acquire are only pebl^les on a path which he must travel before the enjoyment of the broader view is possible, his attitude will soon change. He will not simply grind and memorize but think and inc^uire, or at least grind, think and inquire. Lectures in osteology, to be sure, need not be confined to or even include a rehearsal of the detailed descriptions, however excellent, found in our textbooks of human anatomy. For there certainly are manj' aspects of osteology, a i)roi)er discussion of which will not only invite but command the attention of students. I refer to the many interesting (juestions connected with the development, the growth, form, structure, nutrition, regeneration, transplantation and adai)tation of bones and the significance of variations and deformities, not to mention the long and attractive vista ofTered by comparative anatomy, physical anthropology, or even archeology. Here are a nmltitude of things of sufhcient value to challenge the attention and hold the interest of the maturest students. Surely the timely discussion of these matters can easily convert the dry and dead into a living bone, and a grind OSTEOLOGY REDIVIVUS 307 into a not altogether unpleasant task. Moreover, if the attention of the student were directed more to the living than to the dead bone much would be gained by this alone, for it is after all the secrets and the nature of the living that we are trying to learn from a study of the dead. The plea is not for separate courses in osteology. As far as they are concerned, there is no more reason for them that for separate courses on any other system of organs. Nor is there much more reason for modelling bones than hearts, livers, kidneys, the brain or other viscera. It matters little, to be sure, whether the facts in question are presented in a separate course preceding the dissection, or, as is more desirable perhaps, parallel with them and correllated as far as possible with the rest of the subject of anatomy. However, the mere inclusion or omission of a special course on osteology among the courses of anatomy in any institution, no matter how high its standing, does not necessarily imply that the subject is or is not presented as is desirable. But the general considerations on any system of organs are surely of sufficient interest and importance to warrant their presentation in a more or less formal way and separate form. That, however, is purely a matter of individual preferences and of no special moment. The value Ues, not, to be sure, in this or in that method of presentation, but in the value of the facts themselves.' The oldfashioned, separate, preliminary courses in osteology" derived their main use from the fact that the illustrations and descriptions in the texts in use by the students, were often inadequate and that students did not have sufficiently free access to the bones themselves. But these things need no longer be so and it is seriously to be doubted whether many of the oldfashioned lectures were an improvement on the textbook descriptions. Many of those giving them were not trained or interested in anatomy, as a rule, l)ey()nd a knowledge of the elementary facts. They were, after all, professed devotees whose main allegiance was given to the practice of medicine and not to anatomy. It is the wider and the larger outlook that is needed in many places even now. The student nuist learn to Idok behind, not beyond, the facts, for loose generalizations are worse than none. THE ANATOUICAL RECORD VOL, S, NO 5 308 ARTHUR WILLIAM MEYER But unfortunately the suliject-niatter of osteology has been restricted until it is devoid of interest and the study of it has become a repulsive task. But that is not the fault of the subject. Under such conditions it is wise that special courses in it be oinitted. We have an inconiparal)le legacy which deserves the best presentation that time and the abiUty of the instructor permit. There is absolutely no reason why the study of osteology should be limited to the minimum of what is suppof<ed to be needed by the future practitioner. That is indeterminable. To be sure, if anatomists neglect to see to it that students of medicine have the knowledge of anatomy indispensable in practice, then others must and will see to it. But unfortunately a limitation of the subject to what is supposedly needed in practice has very largely been the custom not only in the teaching of osteology, but in the presentation of the entire subject of human anatomy. Any subject in the whole range of the medical or in other sciences would be sterile if so reduced and taught. There is, of course, a certain minimum of information which every medical student nuist have to l)e a safe practitioner of medicine but the presentation of the subject should not therefore be so limited. Not that anatomists cherish the foolish desire to make disciples out of most medical students. Some of them are and may become, good dissectors during their years of training, but an anatomist verily nmst ever be the ]3roduct of longer seasons, of riper years and broader perspectives. This holds, I take it, even if we do not entertain for anatomists the exalted conception of Paracelsus regarding physicians, viz., that they are not made in highschools but are born and made by the Lord himself! While, then, few students can or will ever become anatomists, I see no reason why the subject should not be presented as though all would become anatomists. Nor is it therefore necessary to overlook or to regret the fact that we are training futun^ practitioners. The frank recognition of this fact makes the adoption of the broader view all the more necessary and important to these individuals whose future life's work will be barren and a drudgery without it. There may not be much untilled ground in osteology but the student's conception of and interest in a sul)ject is l)ut rarely determined by such consider OSTEOLOGY REDIVIVUS 309 ations. The latter applies only to the few — the very few — and these will not confine their attention to osteology alone but will claim the whole field of anatomy in which the harvest has already been a rich one even if full many a sheaf lies yet ungarnered. Unfortunately, most of our textbooks have omitted what might be called introductory chapters on general anatomy, in which the fundamental facts regarding the various systems are presented. Some of them contain a few sentences or paragraphs on the general aspects of the various systems but no connected account is given. For a connected account of so simple a thing as the skin or the superficial fascia, for example, the student must search the Uterature or special monographs on the subject. It seems to me that there is every reason why the student should be assisted in welding the discouraging number of details on each subject into a consistent whole, largely through the medium of the many interesting general considerations or special relations. The wealth of these is as great as the need for their presentation is grievous. That is also true of the question of muscular movements, to a knowledge of which practicing neurologists have added so much in recent years by their study of injuries and paralyses. Nevertheless, our textbooks of anatomy continue merely to tabulate muscular activity as though each muscle acted as independently as the enclosure about its name in the customary table would seem to suggest. It is no wonder that the student thinks of independent, isolated motions rather than that of associated common movements, of facts instead of their significance. In this case a subject of surpassing interest and of great practical value is reduced to the level of a table which however useful, gives not the least intimation of the great complexity of muscular movements. Surely the work of Bell, Duchenne, Hunter, Winslow and others, deserves better than this, and while I fully realize that the daj's of Haller and Johannes jMiiller are long passed, yet here is an opportunity for reform. No one pretends ' ' to make all knowledge his province" and I gladly leave to physiologists what is theirs, but there surely is sufficient cause for Koux's criticism that "Die menschlichen Anatomen, welche Funktionen der Gelenke und Muskeln and der Leiche studieren und nach diesen Befunden lehren. sind 310 ARTHUR WILLIAM MEYER in diosein P'alle iinmor schon reine Analytiker gewesen. Doiin sie orforsclien die fndgliclicn Funktionen der einzdnen Gelenke und der einzelnen ]Muskeln. Manche aber erachten dann diese Er^.cbnisse ohne weitere Priifung als fiir die Lebenstatigkeit giiltig, obschon in der Wirklichkeit des Lebens diese einzclen Funktionen numchnial gar nicht vorkommen. ' ' There are those who have long beUeved in the presentation of the whole subject from a functional standpoint, as counselled recently l)y a distinguished investigator. To ask constantlj' how a structure is built without stopping for a moment to inquire why is it built thus or so, would hardly seem possible for intelligent beings and would reduce the stud}' of anatomj' to mere memorizing, for as has been well said; "Und Anatomic allein getrieben, ohne Bezugnahme auf die Funktion, scheint manchmal eine recht sterile Wissenschaft. " There is, to be sure, a limit to the capacity and knowledge of every one of us, yet the embryological, comparative anatomical, and anthropological aspects must not be forgotten, for these things alone can re-in\'igorate what has been reduced to the dead level of detached facts, and make both teaching and learning interesting. For these twm brothers, of course, must ever travel hand in hand even if one or the other, by birth or station or both, is the favored partner of the two. So instead of banishing osteology I would re\'amp and rejuvenate it. I would return to the custom of our great exemj^lars. It is true that the whole subject of human anatomy has some more or less unavoidably forl)i(lding aspects, yet these are purely incidental and in spite of them human anatomy is of sufficient interest to command the attention of other than medical students. Such an achievement is worth while and will do much, I take it, to free anatomy from the onus cast upon it in the past. It has carried the Ijurden of the old dissecting-room atmosphere, oldfashioned lectures and the things that were associated with it and with them, altogether too long, and what a burden it was and is! Externals need no longer ])urden us, for a practically odorless dissecting-room need no longer remain a remote possibility, but may become a present accomplishment. OSTEOLOGY REDIVIVUS 311 It is not a question of making anatomy more interesting. Human anatomy is interesting and those who do not think so should not profess to be its devotees, nor should they who consider teaching a drudgery be permitted to teach. These words are not meant as a dictum but as a statement of fact which needs emphasis and deserves more general acceptance even in these days. I have no ex cathedra opinions to offer on any subject but I ho'pe that this gentle counterblast will not idly vex the air" of a silent night and like the cuckoo in June "be heard but not regarded. " BOOKS RECEIVED The receipt of piihllcntlons that may he sent to any of the five biological Journals published by The Wlatar Institute will be acknowleildcd under this heading. Short reviews of books that are of special Intcnst to a large number of biologists will be published In this journal tiom time to time. DEVELOPMENT AND ANATOMY OF THE NASAL ACCESSORY SINUSES IN MAN. Based on 290 lateral nasal walls, showing various stages and types of development from the sixtieth day of fetal life to advanced maturitj*; by Warren B. Davis, M.D., Corinpa Borden Keen Research Fellow, Jefferson Medical College, Philadelphia. Octavo, 172 pages with 57 original illustrations by Dorothy Peters. Philadelphia and London: W. B. Saunders Company, 1914. Cloth, 3.50 net. Foreword. The literature concerning the embryology, later development, and adult anatomy of the nasal accessory sinuses, is rather abundant, yet the differences in the views expressed — especially concerning the extent of development during the j-ears of childhood — seemed sufficiently great to warrant further study. The author therefore has collected and carefully studied this series of preparations of the accessory sinus areas — which series covers the various stages of development from the sixtieth day of intrauterine life to advanced maturity — hoping to supph' information regarding some few points with which we have been imperfectly acquainted, on account of the scarcity of specimens showing the conditions present during the years of childhood. Deductions drawn from a few observations are open to fallacy, owing to variations in the extent and type of development as found in different specimens of approximate^' the same age. In this series an endeavor has been made to obtain a sufficient number of cases showing the various stages of development to make the general averages of practical value. The bodies of children between the ages of two and sixteen years being seldom obtainable in the dissecting rooms of European institutions as well as in America, it was necessary, in order to complete such a series, to develop a technic by which the accessory sinus areas could be removed en masse at the time of postmortem examinations, and still allow reconstruction of the face without marked disfigurement. Ninety-six of the cases in this series were thus obtained from the postmortem room of the Friedrichshain Krankenhaus, BeMin. The material'for the other post-natal preparations was furnished by the Daniel Baugh Institute of Anatomy of Philadelphia. CARCINOMA OF THE THYROID IN THE SALMONOID FISHES. An investigation and experimental study conducted jointly by the Gratwick Laboratory of the State Institute for the Study of Malignant Diseases, Buffalo, N. Y., and the United States Bureau of Fisheries, Harvey R. Caylord, M.D., Director, State Institute for the Study of Malignant Disease, Buffalo, N. Y., and Millard C. Marsh, Biologist, State Institute for the Study of Malignant Diseaso, formerly Scientific Assistant, United States Bureau of Fisheries, with the collaboration of Frederick C. Busch, M.D., Internist, and Burton T. Simpson, M.D., Pathologist, State Institute for the Study of Malignant Disease; 162 pages and 127 figures (9 in colors); from Bulletin of The Bureau of Fisheries, Volume 32, 1912, Document No. 790, issued April 22. 1914, Government Printing Office, Washington, D. C. 312 113 A TRANSITIONAL TYPE OF CERVKWL RIB BARTON G. DUPRE WITH A co:m:\ient,ary T. WIXGATE TODD From the Anatomical Laboratory, Western Reserve University, Cleveland. Ohio FOUR FIGURES The case of cervical rib about to be described, occurred in the dissecting room of this School, some few months past. Although much literature is available on the subject of cervical ril). we have thought it advisable to give as full a description as possiV^le. of the present instance, because it exhibits certain interesting points which are not clearly dealt with in the majority of previous records. Some facts, however, I have been unable to ascertain, o\\'ing to dissection having been performed on the subject previous to the discovery of the condition. DESCRIPTION OF SPECIMEN Subject VI: ]\lale, white: age, 45 years. Clinical records give no indication of right- or left -handedness. CONDITION OF BONES 1. Occipital bone and condyles, normal. 2. Vertebral column: No scoliosis or other curvature. Atlas vertebra, normal; axis vertcl)ra, normal; 3rd and 4th vertebrae; normal vertebrae, with bifitl spines. 5th and 6th vertebrae, spine single; single foramen transversarium on both sides. 7th verebra (fig. 1), spine single; this is the first rib-liearing vertebra. On eacli side the foramen transversarium is completetl by the rudimentary rib. Left transverse process is du'ected horizontally outward: tlie riglit is shorter and inclined somewhat 313 THE ANATOMICAL RECORD, VOL. 8. NO. 6, JUNE, 1914 314 BARTON r.. Dl'PRE AND T. WINGATE TODD raiidally. Sth to \\H\\ vortol)rao (inrlusivoV nonnal ril)-l)('arinp; v(M't(^l)ra(\ Transverse jiroeesses of Sth \erte))ra {lirected upward and outwtu'd. 20th to 24th vertebrae (inclusive), normal lumbar vertel)rae. 2r)th vertel^ra, nonnal 1st sacral vertebra. Sacrum, normal; coccyx, fused to sacrum. The vertebral column may be arranged thus: Atlas; axis; four non-rib-bearing vertebrae; thirteen rib-bearing-vertebrae; five non-rilvbearing vertebrae; sacrum. 3. The sternum presented no irregular features. Episternal bones were absent. The 2d costal cartilages articulated with the junction of manubrium and body. The first seven costal cartilages on each side articulated with the sternum directly. A lateral articulation was jiresent between the 5th, (ith and 7th costal cartilages. The costal cartilages of the Sth and 9th ribs on both sides were connected indirectly with the sternum through their articulation with the costal cartilage immediately preceding. The 10th, 11th and 12th dorsal ribs presented free ventral extremities. Rudimentary ribs (fig. 1) Right side. The right rudimentary rib was fused at itJs head and tubercle with the body and transverse i^rocess of the seventh vertebra. It represented a free downwardly projecting pointed outer extremity. No fibrous band was present to connect the free extremity with the first complete rii) or the sternum. The length of the rib from head to free extremity was 3.5 cm. The upper aspect presented a well marked groove for the lodgement of the 7th nerve. This groove curved round the ventral side of the rib so that the nerve in the dissection was found emerging apparently hrlow the rib. Lateral to the groove the upper aspect was rough for the attachment of the large intertransverse nuiscle which ran from the (Uii to tli(^ 7th transverse process. The tip, lower asi)e('t and dorsal bon^M' gave origin to the sinall scalenus medius muscle. Left side. On the left side tlu" rudiincMilary rib was longtM- than on the right. It presented head and tubercle, which, however, were not fused with the vertebra as on the right side but articu TRANSITIONAL TYPE OF CERVICAL RJB 315 lated with body and transverse process by means of rudimentary joints. As on the right side the rib presented a free pointed extremity projecting downward and outward and -^-ithout fibrous connection to sternum or first complete rib. The length of the rib measured along the central line of the upper aspect from head to free extremity was 5 cm. The upper aspect of neck and shaft displayed a groove for the lodgement of the 7th nerve. There was also a tiny transverse groove for the passage of the deep cer^'ical I"ig. 1 .Seventh cervical vertebra with rudimentary ribs; first dorsal ribs. One-half natural size. The rudimentary ribs lodged th? seventh nerv* on each side in the grooves marked X. On the left side the deep cervical artery crossed the rudimentary rib in the groove, .1. The first complete (dorsal) ribs showed a groove for the subclavian vein, V, but the sulcus subclaviae was absent. artery. Lateral to the nerve groove and on both sides of the arterial channel the upper aspect was rough for the attachment of the intertransverse muscle (cf. right rib). As on the right side the free extremity, under surface and dorsal border provided attachment for the small scalenus medius nuiscle. First complete ribs (tig. 1). These when placed on the table lay quite flat. They were therefore not of the 'rocker' pattern (2). They presented the usual characters of the first rib and displayed grooves for the subclavian vein: the right groove being somewhat l)otter marked than the left. On both sides the sulcus subclaviae was absent. Tlu^ right ril» was 1."^ cm. in length from head to an 31G BARTON (J. DUPRE AND T. WIXGATE TODD terior extremity measured along the center of the upper surface of the shaft. The left was 14 cm. in length. Both articulated with the sternum by means of an intennediate costal cartilage The angle subtended by each ril) from the horizontal was 45 degrees. The otlier nh^ presented no irregularities, l)ut one or two facts may be mentioned concerning the lower members of the series on each side. The 10th. 11th and I'ith complete ribs were of the 'floating' variety. Eleventh complete ribs. Tyi)i('al appearance; length on each side 19 cm. Last ribs. These, the 12th complete pair, articulated with the body of the 19th vertebra and belonged to the short variety (Pansch) (3). They presented a head but no tubercle, and had a free tenninal extremity. Unlike the 11th j^air. which were very obliquely jilaced. this pair was directed almost horizontally. The length of the right rib was G cm.; that of the left, 5.5 cm. Scalene group of muscles (figs. 2 and 3) It is to be understood that these muscles were similar on both sides except where differences are indicated. Scalenus anterior. Origin by tendinous slijis from the anterior tubercles of the transverse processes of the 5th and (ith cervical vertebrae. Normal insertion by tendinous and fleshy slips into the inner border of the first complete rib. Scalenus medius. Origin by mixed fleshy and tendinous fibers from the outer border and adjacent part of the lower surface and tip of the rudimentary rib. Insertion to the upper aspect of the dorsal three-fifths of the first complete rib. On both sides the suj)erficial fibers of this muscle were continuous with the intertransversalis muscle wliich had its insertion into the upper surface of the rudimentary rib. Scalenus posterior. Origin by tendinous slips from the jiosterior tubercles of the transverse processes of the 2nd, 3rd, 4th, 5th and 6th cervical vertebrae. The insertion of the bulk of the nmscle was by tendinous fibers iiilo the outer surface of the second TRAXSITIOXAL TYPE OF CERVICAL RIB 317 M. SCALENUS MEDIUS^ VIM IX M. SCALENUS ANTERIOR SITE OF RUOIMENTARV RIB SUBCLAVIAN ARTERY M SCALENUS MEOIUS M SCALENUS MINIHUS Fig. 2 Dissection of scalene nuiscles on right side. One-half natural size. The relation of the muscles to the subclavian artery and the nerve-trunk is shown. M. scalenus posterior is not included in the drawing : the nerve-trunks arc indicated by numerals. Fig. 3 Dissection of scalene muscle.-^ on the left side. One-half natural size. The relation of the subclavian artery and nerve-trunks to the muscles is illustrated. M. scalenus posterior not shown; nerve-trunks indicated by numerals. 318 BARTON G. DUPRE AND T. WING ATE TODD cdinploto rib. Some of tho doopor fihors woro inserted into the rudiniontary and first complete ril)s. Scalenus minimus. This muscle was present on the left side only. Its origin was by tendinus fibers from the anterior tubercles of the transverse processes of the oth and 0th cervical vertebrae. Its insertion was into the inner border of the first complete rib iimnediately dorsal to and partially continuous with the insertion of the scalenus anterior. The intercostal group of muscles. These showed no direct continuity between their fibers and those of the scalene muscles. The arteries The arteries were arranged as follows: The right subclavian artery arched outward in its course, there being a marked isthmus where it passed ventral to the free extremity of the rudimentary rib and deep to the ]\I. scalenus anterior (fig. 4). This constriction was not due, however, to any effect of the rib or muscle. The isthmus of the artery measured 9 mm. in length of which 4 mm. lay distal to the outer border of the scalenus anterior. Its branches were all given off from the first part, namely, vertebral, thyreo-cervical, internal mammary and costo-cervical. The deep cervical artery arose from the costo-cervical vessel and passed backward between the rudimentary rib and the first complete rib. The left subclavian artery also arched outward in its course and presented an isthmus at the sunmiit of the curve just beyond where the vessel passed between the scalenus anterior and scalenus minimus muscles. The narrowing of the vessel was more marked than on the right side. The branches of the left artery included the vertebral, thyreo-cervical and internal mammary vessels from the first part and the costo-cervical from the second part. The deep cervical artery, a branch of the costo-cervical trunk, passed upward and outward deep to the scalenus minimus muscle, then between the 6th and 7th nerve-trunks of the brachial plexus and over the upper surface of the rudimentary rib where it presented an 'isthmus' and occupied a groove on the Ixme. TRANSITIONAL TYPE OF CERVICAL RIB 319 Thence it traversed the substance of the intertransverse muscle deep to the scalenus posterior after which it gave off two terminal downwardly directed branches. In its course the vessel supplied twigs to the scalenus minimus, intertransverse and scalenus posterior muscles. Fig. 4 Drawing to show relation of nerve-trunks to cervical ribs. One-half natural size. The subclavian arteries have been displaced downward to give a better view of the lower nerve-trunks. Measurements of subclavian arteries mm. Length of isthmus on left side 12 Length of isthmus on right side 9.0 Diameter of isthmus on left side 3.5 Diameter of isthmus on right side 5.0 Diameter of left artery above outer border of first complete rib 7.0 Diameter of right artery above outer border of first complete rib. . 5.5 No flattening of the arteries was observed. The cirsoid fonn described by Mr. Todd ( 1 ) was not well marked in this specimen. The wall of the arteries was not histologically examined. 320 liAHTOX G. DUPRE AND T. WIXGATE TODU The pleura The pleura was in divcvt contact witli, though not adherent to, the rudimcMitarv lih on hotli sides. The nerves On investigation of the nerves the following results were obtained: The brachial plexus on the right side was constituted by the 5th, 6th, 7th, 8th and 9th nerves with few fibers only from the 4th nerve. These appeared in the following manner: 5th nerve, between intertransversales. 6th nerve between scalenus anterior and intertransversalis passing above the rudimentary rib. 7th nerve, between scaleni anterior and medius ]:)assing inniiediately beneath the tip of the rudimentary ril). This nerve, on deeper dissection, proved to be the one which lay immediately on the rudimentary rib and was responsible for the nerve groove in figure 1. .Sth nerve, between scaleni anterior and medius. 9th nen'e, volume about one-half the size of the Sth nerve and three times the size of the first intercostal nerve. It joined the Sth nerve medial to the anterior bordei- of the scalenus medius muscle and below the rudimentary ril). The brachial ])lexus on tlu^ Ic^ft side was formed ))y the Sth, 6th. 7th. Sth and 9th nerves with the larger proportion of the 4th nerve. These a|)peared in the following manner: 5th nerve between scalenus minimus and scalenus i)osterior (intertransversales deeper), (dh n(M-v(\ l)etween scalenus minimus and intertransverse muscles. 7th nerve, between scalenus minimus and intertransverse muscles, also passing inunediately above the rudimentary rib. Sth nerve, between the scaleni mininuis and medius and emerged just below the tij) of the rudiiiuMitary rib. 9th nerve: size al)out twice that of the first intercostal nerve. It joined the Stli nerve IS mm. medial to the anterior border of the scalenus modius nmsdcv On neither side was there any comnmnication of the 10th nerve with the plexus. The exact arrangement of the brachial trunks and cords had been disturbed before I was able TRANSI'PIOXAL TYPE OF CERVICAL RIB 321 to examine them. There were no direct sympathetic filaraients traceable to the 10th nerve. The stellate ganglion on each side lay at the level of the neck of the first complete rib. There were numerous fine fibers running from the sj^mpathetic chain to the periosteum of the rudimentary rib on both sides. The sinu- vertebral nerve was not found on either side. On each side the first intercostal nerve supplied the first space by means of two twigs, the upper of which crossed the under surface of the first complete rib at about the junction of the dorsal and middle thirds of the rib. It then passed downward again to reach the anterior end of the first true intercostal space. The 20th nerve was the subcostal. The lumbar and sacro-coccygeal plexuses presented no irregularities. COMMENTARY T. WIXGATE TODD The reasons for publication of the present example of cervical rib are three in number: First, the description aptly illustrates the particulars ascertained in the systematic investigation of the ribs of all subjects utilized in this laboratory. Second, the specimen presents on the one side (right) a tA^^ical 'buttress' type of cervical rib and on the other (left) a 'true' rib. Third, and the most important, is the presentation by the case of an instance where the 7th nerve, and not that formed by the combined 8th and 9th, is the trunk open to mechanical damage. Since I wrote the previous account of certain examples of rudimentary rib (1), other articles have been published on the sulv ject and our knowledge has considerably increased. It may be well, while discussing the present exam]ile. to include reference to other related topics which have arisen during the past two years. In the present example there can be no doubt whatever as to what the radiograi^hic appearance would have been, had the Department had the gooil fortune to possess such an apparatus. 322 HMM-nv (;. DIPKE AND T. WINGATE TODD What Dr. (iill)ort Scott tonns a 'true' rii) would have ))een ajiparent on the left side and what he calls a 'buttress' type would have heen seen on the right (4). The 'buttress' variety appearing in the skiagram as a true enlargement of the seventh cervical transverse process, however unlike the 'true' example, is nevertheless invariably a rudhnentary rib, fused with the actual transverse process (5). Hence, if differentiating tenns are to be used, 'fused' and 'articulating' would be more descriptive and correct than those utilized by radiographers at present. The slope Of the transverse processes of the 7th cervical vertebrae illustrates the contention of Dr. Wood Jones that it must not be relied on for a decision as to which rib is rudimentary (6). Both rudimentary ribs in this case presented groovings for the seventh cervical nerve, a point to which reference will be made later. It would seem that as there was no connection with first comi)lete rib or with manubrium, the lowest brachial trunks sli])i)etl down below the level of the rudimentary ribs. Indeed on the right side, as may be seen in figure 4, the seventh nerve almost succeeded in lying beneath the level of the rib, the groove produced by it occupying the ventral aspect of the bone, so that on superficial dissection the nerve actually appeared below the rib (fig. 2). It has been stated by Wood Jones that the sulcus subclaviae never lodges the subclavian artery and that the first rib exhibits grooves for nerves and vein alone (7). With this view I am still unable to agree. The ])resent example illustrates the grooving of a seventh cervical rib, l)v an arter>'. On the left side a channel (marked A, fig. I) shows the site where {\\o cervical artery crossed the bone after passing betweeen the sixth and seventh nervetrunks. With regard to scoliosis, it may be pointixl out that this has only been present in one of our dissected series, namely, subject ( ' f)f the previous paper (1 ) . The absence of scoliosis may possibly have had something to do with the non-appearance of symptoms in our cases; see Murphy (S). The muscles of the present instance confirm the view that the scalenes form one mass which mav be subdivided variouslv in TRAXSITIOXAL TYPE OF CERVICAL RIB 323 different individuals, thus giving rise to the alteration in size or or even absence of component bundles of fibers which have been dignified by special names. Here the scalenus posterior was large the scalenus medius verv^ small: a condition the reverse of that which normally obtains. The homology- of the scalenes and intertransverse muscles is well shown : but see also (1). The record of the subclavian arteries in this case indicates by the site and extent of the isthmus that the constriction was not due to muscular pressure. It is but fair, however, to observe that an isthmus occurred in the left deep cervical artery as it pa.ssed over the rudimentary rib, although this was not the summit of its curve (9). It is especially to be not^d that the deep cervical artery was raised on the left side but not on the right. On the left side the vessel passed backward above the rudimentary- rib and apparently was the artery' belonging to the segment cephalad of that to which the vessel normally belongs. It is, however, in relation to the nerve-trunks that one encounters the most striking feature of the present case. From the clinical description of certain cases of cervical rib it is clear that in some way the seventh root has been involved and not the roots caudad of this. Or again, the symptoms indicate involvement of the seventh root in addition to the other two. This would seem to be the case in certain of the instances where s\Tnptoms first appear on the radial border of the hand. I feel convinced tliat in some of these the conummication between the median and ulnar nerves conveys the fibers to the preaxial border. But the case described in this pajier clearly shows how the seventh root may become involved in the lesion and chiefly for this reason I have urged M. Dupre to investigate the cadaver thoroughly. The arrangement of the brachial jiloxus on the two siiles tends to confirm Wood Jones' view that there is a definite relation l>etween the rudimentary rib and the plexus (10) (11). Against this must be placed previous cases of mine and the fact that the s>nnptoms may bo produced by an apjiarently normal first rib. V24 HAHTON (i. DIPRE AND T. WINGATE TODD sr.MMAin' 1. ^^'llatevcr tlio ra(li<)^rai)hic' appearance, there is no such thing as a true enlargement of the transverse processes of the seventh cervical vertebra. The so-called enlargement is, in every instance, a rudimentary rib, 2. Certain cases which exhibit symptoms of "cervical rib" involving the seventh cervical nerve root are aptly illustrated by the present instance, in which the lowest trunk of the brachial plexus lay beneath the rudimentar}- rib and therefore possibly less exposed to a mechanical lesion. The seventh root on the other hand, contrary to the usual condition found in dissection, lay upon and grooved the rudimentary rib on each side. LITERATURE CITED (1 ) Todd, T. W. 1912 Cervical rib. Jour. Anat and Phys., vol. 4G, p. 244. (2) 1911 Relations of the thoracic operculum. Jour. Anat. and Phys., vol. 4.5, p. 291. (3) P.w.sfH 1911 Quoted bj' Poirier P. in Osteologie, in Traits d'anatoniie huinaine; 2nd Ed. T. 1, p. 396. (4) Scott, S. Gilbert 1912 Cervical ribs. Brit. Med. Jour., vol. 2, p. 483. (.5) Todd, T. W. 1912 Costal anomalies of the thoracic inlet. Anat. Anz., lid. 41, p. 257. (6) JoxES, F.Wood 1912 Radiographicdiagnosisof rudimentary ribs. London Hospital Gazette, vol. 18, p. 166. (7) 1910 On the real significance of the 'sulcus subclaviae.' Anat. .\nz.. lid. 36, p. 25. (8) MiKPHY, J. B. 1906 The clinical significance of cervical ribs. Surg. Gyn. Obstet., vol. 3, p. 514. (9) Todd, T. W. 1912 The vascular symptoms in 'cervical' rib. Lancet, vol. 2, p. .362. (10) Jones, F. Wood 1911 \'ariations in the first rib associated willi changes in the constitution of the brachial iiexus. Jour. Anat. and Phys., vol. 45, p. 249. (Ill 191.1 The anatomy of cervical ribs. Proc. Roy. Soc. Med., vol. 6. (clinical section) p. 95. A a\SE OF STYLO-HYOID OSSIFICATIOX GEORGE P. LEOXHART From the Anatomical Laboratory, Western Reserve University, Cleveland, Ohio TVSO FIGURES Stylohyoid ossification has received attention from time to time but such wTitings "as are existent on the subject have most frequently been confined to the study of macerated specimens. There is thus still room for exact descriptions of instances which are discovered before the dissection has proceeded to any considerable extent. The present specimen was obtained in the dissecting-room of the Western Reserve University and was handed over to me for investigation by ^Ir. Wingate Todd. It occurred in the body of a white man fifty-five years of age. whose death was occasioned by alcoholism. As but little dissection had previously been done on the specimen, this has been a favorable opportunity, not only to describe the bony structures, but also to discuss the relation of the anomaly to the soft parts in the immediate neighborhood. Enquiry into the clinical history of the individual did not elicit any symptoms referable to the condition, and definitely negatived any disability in speech or swallowing. Dissection revealed a complete bilateral chain of ossicles representing the second or hyoid arch. This is sho\^^l in the accompanying radiogram. The 'prolongement hyoidien' formed a stout irregular mass which projected some 13 nun. from the temporal bone. This was succeeded by a bar of bone, ovoid in cross-section. On the left side there was little to indicate that this was composed of two fused elements. On the right side, hcnvever, the bar displayed a thickening which reacheti a maxinunn 22 nun. from its upper extremity, and probably represented the original site of fusion. 325 326 GEORGE P. LEONHART Fiji. 1 KadioRrain of head of man fifty-five years of a^o. One-fourtli natural size. The soft parts are still in jwsition, but the oeeiimt, vertebral column and left half of the mandible have been removed to show more clearly the i)Osition of the ossified stjlo-hyoid ligaments. The i)oin1er indicates the articulation between the tymi)atu)-hyal and stylo-hyal elements on the rijjht side. A small backwardly <lirected projection from the proximal extremity of the stylo-hyal is ai)i)arent. The left stylo-hyoid ossification is not in focus; it can be .seen, however, as a dark shallow passing upward and backward to the interval between the molar teeth seen on the radioRrani. The body of 1 lie hyoid and t he greater cornuM on t he right side arc dearly shown. Fig. 2 Key to radiogram. < )Mi'-fourt h ii;il ur;d size. In order more cle;uly to dis|)lay the stylo-hyoid chain, the vertebral column, occi|)u( and left half of the mandible were removed. The radiogram was then taken oblicpiely from behind. The right side of the hyoid app.-tratus is arranged in focus; the left side appears as a dark shadow. STYLO-HYOID OSSIFICATION 327 On each side, the bar of bone was succeeded by a lesser horn which was fused with the hyoid bone at the junction of the bod}' with the greater cornu, this latter having not 3'et become ossified in one piece with the hyoid body. The measurements of the ovoid bar were the following: mm. Length on left side 70 Length on right side 60 Greatest diameter on left side 5 Greatest diameter on right side 6 Least diameter on left side 3 Least diameter on right side 3 The lesser cornua were mere projections of cartilage, not differentiated from that which united the bod}^ with the greater cornua. There being some confusion over the nomenclature of the various bony elements it may be well to define exact I3' what is meant by the terms used. Poirier (1) adopts the following names for the four elements represented: (1) The tympano-h^'al for what has above been indicated as the 'prolongement hyoidien ;' (2) The stylo-hyal; and (3) The cerato-hyal for the proximal and distal parts respectively, of the bar of bone just described. The ceratohyal is usually represented in homo by the stylohyoid ligament. (4) The hypo-hyal corresponds to the lesser cornu. This form of nomenclature was followed by Dwiglit in liis recent paper on the subject (2) and is retained in this article. A different definition of terms is given by Keith (3). Pseudo-articulations wore present on lioth sides uniting tymj)an()-hyal witli tlio ]ir()\iinal end. and tlie liyjio-hyal witli the distal end of the long i)ar. The joints consisted of white fibrocartilage with no defined joint cavity. On the other hand, the tympano-hyal on both sides was fused to the rest of the temporal bone; there was but bare indication that the long bar consisted of stylo-hyal and cerato-hyal elements; and there was no joint between the hypo-hyal cartilage and iho hyoid itself on either side. Thus all the elements w(Me ossified with the exception of the hypohyals. The greater conuia displayed no terminal nodules of cartilage at their free jiosterior extremities. 328 GEORGE I'. LEONHART The I)()(ly of Ihc liyoid did not disj)lay tho 'curvcMl bar" referred to\ Pars()ii8 us indiciitiiig the separate constitution of this bone by the 2nd and 3rd arches (4), but exhibited a median vascular foramen which may be a suggestion of the original double origin of the l^ody. Xo representative of the glosso-hyal was present.

Tlie ujijier extremity of the stylo-hyal on l)oth sides j)resented a slight backwardly projecting process distantly reminiscent of, tliougli ])robal)ly not homologous with, the similar process on the ungulate stylo-hyal (5). The proximal ends of the stylo-hyals were 73 mm. apart. The breadth of the skull between the most prominent parts of the mastoid processes was 120 mm. The distal extremities of the cerato-hyals were 30 mm. apart; cf. (Jrubor's case (loj.

These measurements are given to show that the processes in this case did not constrict the posterior nares as occurred in the second of Liicke's cases (6). The fused stjdo-and cerato-hyals I^rojected downwai'd and inward. On the left side the bar of bone formed an angle of 50 degrees downward and forward and 75 degrees downward and inward. On the right side these measurements were respectively 65 degrees and 00 degrees.

The question of ossification being normal or pathological, it would be profitless to enter. The bone formation resulted doubtless from extension of the normal ossific process of the hyoid aj)I)aratus, which in such cases, as in instances of 'cervical" ril)s, probably takes place at a much earlier date than used to be suspected; (for a discussion of dates see Dwight's pajier). The present case is similar to that recorded by Turner but his instance was unilateral (7).

T]\r following ol)servations on the myology seem to be warranted:

The origin of the stylo-hyoid was, on l)olh siiles, from the posterior aspect of adjacent ends of the tympano- and stylo-hyals, by tendinous fibers.

Tlie stylo-pharj'iigeus displayed an origin by nuiscular fibers from the same situation as did the stylo-hyoid l)Ut from the iimer aspect of the process.

STYLO-HYOID OSSIFICATION 329

The stylo-glossus arose by tendinous fibers from the anterior aspect of the whole length of the stylo-hyal element. There was, naturally, no stylohyoid ligament present.

Aluscles which were looked for, but of which no vestige was found, were the hyoideus latus and hyoideus trans versus. It was thought that possibly some remnant of these muscles, so well marked in Ungulata, might be found in homo in such a case as the present.

The masto-styloideus of ungulates (8) was represented only by very dense fascia passing from the mastoid process to the tympano-hyal and adjacent extremity of the stylo-hyal on both sides of the body. It formed part of the fascial bed for the parotid gland. No fibers could be traced directly into either the stylo-hyoid or stylo-pharyngeus.

On the right side was an example of the deep stylo-hyoid of Sappey (9). It arose from midway along the posterior aspect of the stylo-hyal by tendinous fibers, gave place to a small fusiform bell}^, and terminated in a fibrous bundle inserted into the hypohyal. According to Macalister this muscle represents one of the muscular bands found in bony fishes (10); see also Gavarde's example quoted by Macahster (16). On the left side the deep stylo-hyoid nmscle was not found.

The relation of the styloid process to the bloodvessels confirmed the description already given by Dwight. On palpation through the mouth, the elongated stylohyoid process could be felt on each side, immediately below and l)ehind the tonsil. In the cadaver it produced a distinct, though but slightly elevated ridge where the base of the tongue formed the anterior boundary of the \"allecula. Dissection showed it to lie on the outer aspect of the bucco-pharj'ngeal fascia and distant by 5 mm. from the oral pharyngeal mucous membrane. Its disposition was therefore similar to that of the process recorded In- Kyle in his case of fractured styloid (11).

There was no constriction of tlie postei'ior naros. It would seem from Kyle's case, as from the i>resent one, that the ossified ligament may produce no symptoms. In Kyle's case temporary

THE ANATOMIC.VI. KKCORl>, VOL. 8, NO. 6

330 GEORGE r. LEONHART

aphonia, a sensation of constriction in the throat when singing or speaking and loss of the singing voire resulted from fraeture of the i)roeess.

How far complete ossification of the styloid process may be responsible, in certain cases, for clinical symj^toms. is not yet clear. Kichardson records an instance of bilateral long styloid with which occurred post-nasal catarrh, soreness in the tonsillar region, difficulty in swallowing and soreness of the neck after much use of the voice. Moreover, the symptoms were cured by removal of the process (12).

Bigelow's case of the 'clicking woman' mentioned by Dwight, may have been an instance of ossified stylo-hyoid ligament (13). I have not thought it necessary to dwell upon those instances and clinical complications already referred to in detail by Dwight (2).

The ]iosition of the process in relation to the tonsil may be variable according to the length and direction of the bone. In Kichardson's case already mentioned, a shorter process than the one recorded here, lay just within the anterior tonsillar fold and parallel to its course.

It is well to be on one's guard against the possible presence of the subpharyngeal cartilage of Luschka when making a clinical diagnosis of elongated styloid process. This is emjihasized by AMngrave who mentions that besides occurring in the lateral wall of the pharynx, somewhat below and behind the faucial tonsil, the cartilage may also be present in the tonsil itself and in the latter situation, will give resistance to the guillotine (14).

In conclusion, I would express my obligation to Prof. T. Wingate Todd for his help lliroii^lioiil the investigation and in the writing of this article.

STYLO-HYOID OSSIFICATION 331

SUMMARY

1. Complete ossification of the stylohyoid ligament may occur without the production of any clinical symptoms.

2. Associated with the anomaly, muscular variations may be present.

3. A frequent site of such an ossification is below and behind the tonsil in the anterior part of the vallecula where it may be palpated clinically.

4. The situation may vary, especially when the Hgament is not ossified throughout its length. In such a case it may lie in front of the tonsil.

5. Constriction of the posterior nares or oral pharjnix does not occur unless the process is markedly deflected.

6. In making the cUnical diagnosis of ossified stylohj'oid ligament, the occasional presence of the sub-pharyngeal cartilage of Luschka must be remembered.

REFERENCES

(1) PoiRiER, P. 1911 Osteologie. Traite d'anatomie humaine. 2nd Edit.. T.

1, p. 354.

(2) DwiGHT, T. 1907 Stylo-hyoid ossification. Ann. of Surgery, vol. 46. p. 721.

(3) Keith, A. 1913 Human embryology and morphology. 3rd Ed., p. 227.

(4) Parsons, F. G. 1909 The topography and morphology of the human hyoid

bone. Jour. Anat. and Physiol., vol. 43, p. 279.

(5) SissoN, S. 1910 Veterinary anatomy. P. 65.

(6) Lt'CKE. 1870 Practische Bedeutung des abnorm langen und verbogenen

Processus styloides des Schliifenbeins. .\rch. f. path. Anat. u. Physiol., Bd.51,p. 140.

(7) Turner, Sir W. 1902 Hyoid apparatus inman, in which a separate epihyal

bone was developed. Jour. Anat. and Physiol., vol. 36, p. 162.

(8) Windle, B. C. A., and Parson, F. G. 1901 The muscles of the Ungulata.

Part I, Proc. Zool. Soc, London, December, p. 667.

(9) S.\.ppey 1912 Quoted by Poirier in Myologie. Trait(? d'anatomie humaine.

3rd f:dit., T. 2, fasc. 1, p. 239.

(10) Macalister, a. 1897 (Quoted by A. F. LeDouble in Traiti^ dos variations du systdme musculaire do I'homme. T. 1, p. 125.

332 GEOIKJE P. LEONHART

(11) Kyle, J. J. 1909 An;itoiiiy and diseases of the styloid epiphysis Ann.

Otol. Khinol. ami Laryngology, vol. IS, p. 132.

(12) Richardson, C. W. 1909 Elongated styloid process. Trans. Anur. Larynji.

Assoc., p. 171.

(13) BiGELOW, H.J. Quoteil by Dwight; see reference 2.

(14) WiNGR.WK. \V. 1900 Dislocation of the styloid process. Brit. Med. Jour.,

vol. 2, p. 1039.

(15) Grubeh, \V. 1S70 Ucber enorm lange Processus styloideus der Schlafen beinc. Arch. f. path. Anat. u. Physiol, Bd. 50, p. 232.

(16) Macalister,A. 1871 The varieties of the styloid muscles. Jour. .\nat. and

Physiol., vol. 5, p. 29.

A CASE OF :VIULTIPLE RENAL ARTERIES

RICHARD \V. HARVEY

Hearst Anatomical Laboratory, University of California

ONE FIGURE

While cases of multiple renal arteries are numerous, occurring in 43 per cent (Macalister '83) of bodies examined, explanations for their occurrence have depended on insufficient embryological evidence, and have been therefore, largely speculative. Although the present case adds no new fact to our knowledge of the condition, its publication in the light of recent studies (Evans '09), (Jeidell '11) is of embryological interest.

During the regular course of instruction in dissecting, ni\' attention was drawn to the abnormal appearance of the kidneys of a white male subject, Xo. 293. The clinical diagnosis was chronic interstitial nephritis. Both kidneys lay at their normal levels, and in their relative positions. The extremitas inferior was drawn closer to the mid-line than the superior, apparently by several super-numerary blood vessels. In shape the kidneys were much altered from the normal, the right being o\'al and flattened, the left pear-shaped with the larger end cephalad. On lioth organs the hilus was placed on tlie ventral surface. The anterior lip was represented by a low ridge cur\ing laterad across the ventral surface of the kidney and approaching the caudal pole. The normal sinus renalis was absent, the vessels, nerves, and calyces penetrating a broad, smooth, conxex siu'face continuous with the surface of the kidneys caudad and mesad. The posterior lip of the hilus was absent.

The tibnornial form and position of the kidneys in association with accessory renal arteries has been ])ointed out by numerous observers. In many cases the kidneys preserve their foetal lolnilation (Poirier, Broedel, '01). In others the hilus remains on the

333

334 RICHARD W. HARVEY

vontral surfaro of tlio ii}iu\d instead of rotating to the inner border as normally (Tyrie, Young and Thompson). In general the kidney deviates from the normal reniform shape in projiortion to the nmnber of the vessels. Tyrie believed that a moulding of the kidney l^y the abdominal ]iarieties together with rotation of tlie gland by increased arterial pressure modifies its shape, while Young and Thompson thought changes in shape are due to the differences in nutrition varying according to the irregular arterial supjily. On the other hand, Rupert ('13) in thirty-hve out of fifty cadavers, found anomalies of the renal arteries without any change in the nonnal positions of the kidneys, although their shajies were altered. The present case w(41 illustrates the dei)arture from the usual reniform shape, the dis])lacement of the hilus in both glands from the mesial border to the ventral surface, and the undeveloped character of the labia of the hilus. Besides the influence on the rotation of the glands which increased arterial pressure or differences in nutrition may exert, there must be considered the possible mechanical effect of persisting anastomosing vessels derived from the primitive plexus sup]ilying the kidneys. The factors which influence the selection of certain channels of the capillary plexus and the elimination of others remains for future research.

An examination of the kidneys and their vessels removed from the abdominal cavity with portions of the aorta and vena cava showed a normal A. renalis sin. arising from the lateral aspect of the aorta immediately below the A. mesenterica superior and entering the hilus at its cephalic extremity on the ventral surface of the kidney, giving off three branches, one of which, the longest, descends to the middle of the gland before entering, lying dorsad to the normal V. renalis. sin. and the ]')elvis; the smaller branches lie in front of these structures as shown in figure 1.

The normal renal artery is formed from the lateral row of primative aortic branches which supply the mesonephros, terminating in a plexus lying between the reproductive gland, the mesonephrous, and tlie metanephrous (Felix '12). Ilochstetter ('91), Pohlman ('05) and Hill ('05) stated that the kidney does not receive its renal artery until it reaches its definitive position, but

MULTIPLE RENAL ARTERIES

335

Figure 1

by the use of the embryos more completely injected in the younger stages than those used b}' previous observers, Evans showed an early metanephric jilexus arising from the A. sacralis media, later confinned by Jeidell who showed also a source for the plexus from the A. mesenterica inf. The vascular sui:)ply to any organ, as shown by Evans, spreads by capillaries and not as outgi-owths of the permanent vessels from the main vascular trunks. The kidney vascular supply accordingly is derived by retention of certain capillary vessels of the embryonic renal plexus. Broman ('06) derived the nomial renal arteries from the mesonephric arteries, and Felix observed that as the kidney migrates upward and the cephalic vascular supply l)y way of the mesoneiihric arteries becomes sufficient, the caud;U liranches separate from it. until, when the kidney has reached its definitive position, only one persist*^ as the iiermanent renal artery. If, then, one or more of these caudal branches persist they may become accessory. Others have explained multipl(> renal arteries as branches of the renal artery

IVM) UICHAHI) \y. HARVEY

arising sooner than normal, the origin of the branches having travelled in, as it were, and eonie to arise separately from the aorta instead of from one eonunon stem. Kolster (.'01) stated that multij^le renal arteries are derived through premature division of the single normal renal artery, or they may be pei*sisting branches of the renal artery which normally degenerates in embryonic development, but which through some unknown, accidental disturbance during development remain accessory. The latter explanation is similar to ]\IacaUister's who considered multiple^ i(Muil arteries as persisting enlargements of branches which normally exist as fine extra-peritoneal anastomoses between the capsular arteries and those supplying the abdominal wall. Young and Thonijison ( '03) suggested that multiple renal arteries are produced l)y arn^sted development of the kidney. These speculations have now given way to the embryological explanation based on the evidence of injected embryos. ^Multiple renal arteries are persisting embryonic vessels of the capillary plexus supplying the normal embryonic kidney. The anomalies which follow are readily explained on this basis.

On the I'ight side the largest renal branch of the aorta slightly liigher than the A. renalis sin. passes behind the V. cava inf. and enters the cephalic extremity of the right kidney at the median l)()rder. It does not branch. This apparently is a persisting mesonephric artery of the gi'oup which lies dorsad to the embryonic sui)ra-renal body, and therefore enters the kidney more dorsad and nearer the cephalic extremity, than the other vessels (Felix). Just below this branch and arising from the ventro-lateral aspect of the aorta is a large branch which enters the hilus of the right kidney at its cephalic extremity after crossing the ventral surface. It breaks up into three branches which lie in front of the l)elvis and vein. It gives off the A. spermatica interna. This branch is ])()ssibly a persisting mesonephric artery of the group which i)asses through the primative suprarenal body (Felix). The A. spermatica interna arising from an A. renalis dex. is not unusual, being derived from a mesonephric vessel, which as in this ca.se, anastomoses with l)ranches entering the hilus, and finally becomes of less importance than the anastomosing vessels.

MULTIPLE RENAL ARTERIES 337

^Midway between the A. mesenterica inf. which is normal and the bifurcation of the aorta there arises from the ventral surface of the aorta a trunk about 1 cm. in length, giving rise to right and left accessory renal arteries. The branch to the right kidney almost immediately bifurcates, one branch coursing cephalad along the median border of the gland to enter the ventral surface dorsad to the pel\4s, the other branch entering the caudal pole directly. The branch to the left kidney passes dorsad to the ureter and pelvis and enters the caudal pole of the gland by numerous radicals. Portal described a case in which both renal arteries arise from a common stem originating from the front of the aorta. The anomaly is probably due to the apposition of opposite ventral branches of the primative aortae coincident with the fusion of these vessels, resulting in rami intestinales which have anastomosed with the early renal capillary plexus.

From the A. iliaca conmiunis dex. there arises from the ventral aspect a large branch crossing ventrad to the bifurcation of the V. cava inf. and dorsad to the ureter and spermatic vessels, and gaining the dorsal surface of the right kidney to which it su])plies a large branch. Then winding across the lateral border and over the anterior lip of the hilus it enters the ventral surface dorsad to the pelvis. This anomaly has been described frequently. It is the retained embryonic })lood supply of the gland while in its pehic position, probably through rami intestinales anastomosing with branches of the capillary renal plexus.

From the ventral as])ect of the A. iliaca comnninis sin. there arises a branch smaller than the one just descril^ed, ])ursuing a course corresponding to that of the latter artery, and distrilniting itself in a similai' manner. Its origin may be explained in the same way.

A normal \'. ivualis sin. arises l)y four radicals from the ventral surface of the left kidney, crosses the atn-ta to the A. mesenterica inf. receiving the \'. spermatica int. sin. and enters the lateral aspect of the V. cava inf. Caudad to this vein and nearer the median border arises a large vein from several ratlicals, which passes dorsad to the aorta, and enters the dorsad lateral aspect of the y. cava inf.. receixing in its course a large vein. \'. azygos

33S RICHARD W. HARVEY

minor. This anomaly is similar to the examples reported by Froriep (95), who considers it due to a cross anastomosis between the left and the right cardinals, the latter having become the post renal portion of the V. cava inf.

The largest vein from the right kidney arises by numerous radicals from the ventral surface of the glands, receives a branch of small calibre from the caudal pole, and enters the lateral aspect of the \. cava inferior caudad to the level of normal X. renal is sin.

The y. renahs dex. arises from the ventral surface near the anterior lip of the hilum by several radicals, receives the V. spermatica int. dex., crosses ventrad to the A. renalis dex., then cephalad to it, and enters the ventro-lateral aspect of the V. cava inf.

The caudal poles of both kidneys are drained by small veins joining at the level of the l)ifurcation of the aorta to form a common trunk 2 cm. long entering the ventral aspect of the V. iliaca transversus. This anomaly is especially interesting because of its rarity.

The accessory renal veins, like the multiple arteries may be explained as persisting branches of the embryonic renal plexus of veins. Undoubtedly, insufficient attention has been devoted by anatomists to multiple renal veins which are as important to consider as arteries, especially in nephrectomy, (Rupert). The present case shows them to be quite as unusually placed in their relations as are the arteries.

BIBLIOGRAPHY

Brodkl, M. 1901 The intrinsic blood vessels of the kiflney and their signifirance in nephrotomy. Johns Hopkins Bull., vol. 12.

Broman, I. 1006 Uber die Entwicklung, Wandcrung and Variation der Bauchaorten-zweige bei den Wirbcltieren. Ergebn. Anat. u. Entwicklungsesch., Bd. 16.

Evans, H. M. 1909 Bloodvessels of the vertebrate embryos. Anat. Rec., vol. 3.

Felix, W . 1912 The development of the urinogenital organs; (article in Human embrjology, Keibel and Mall, vol. 2).

Froriep, A. 189.5 Uber eine verhaUnismiissig haufigc Varietiit in Bereich der unteren Hohlvcne. Anat. Anz., Bd. 10.

MULTIPLE RENAL ARTERIES 339

Gray, G. M. 1906 Multiple renal arteries. Anat. Anz., Bd. 29.

Hill. E. C. 1905 On the first appearance of the renal artery, ami the relative development of the kidneys and Wolffian bodies in pig embryos. Johns Hopkins Bull., vol. 16, no. 167.

HocHSTETTER, F. 1891 Entwicklungsgeschichte des Gefassystems. Ergebn. Anat. u. Entwicklungsgesch., Bd. 1.

Jeidell, H. 1911 A note on the source and character of the early blood vessels of the kidney. Anat. Rec, vol. 5, no. 2.

Kater, X. W. 1902 Case of multiple renal arteries. .Tour. Anat, und Physiologie, vol. 36.

KoLSTER, R. 1901 Studien fiber die Xierengefasse. Zeitschr. f. Morphol. und Anthropol., Rd. 4.

Macallister, A. 188.3 Multiple renal arteries. Jour. Anat. und Physiol., vol. 17.

PoHLMAN, A. G. 1905 A note on the developmental relations of the kidnej' and ureter in human embryos. Johns Hopkins Hos. Bull., vol. 16.

PoiRiER ET Charpy 1901 Traite d'anatomie humainc. T. 2.

Rupert, R. R. 1913 Irregular kidney vessels in fifty cadavers. Surg. Gyn. and Obstet., vol. 17, no. 5.

Tyrie, C. C. B. 1894 Axial rotation of the abdominal aorta, with associated abnormalities of the branches. Jour. Anat. and Physiol., vol. 28.

Young AND Thompson 1903 Multiple renal arteries. Jour. Anat. and Physiol., vol. 38.

CO.M-MIMCATIONS FKO.M SCIENTIFIC INSTITUTIONS

Biologische Versuchsanstall dcr Kaincrlichen Akademie der Wissen schaflen in Wicn.

Since January 1, 1914, the B. V. A. at Vienna (ii, Prater, Vivarium) has passed into the possession of the Mennese Imperial Academy of Science. The Institution in fi;eneral serves the purposes of the experimental investifjation of ( )rfi;anisms, especialh' experimental Morphology and develojimental Physiology, also of comparative Physiology and the borderlands of Biophysics and Biochemistry.

The Anstalt" is an Institution for research, not for systematic education. The Academy of Science has appointed a committee of trustees (J. V. Wiesner, president; S. Exner, vice-president; Becke, Hatschek, H. n. Meyer. INIolisch, Wegscheider), Hans Przihram and Leopold von Portheim remaining directors. Paul Kammerer has been appointed chief-assistant (adjunkt) by the state. Applications for research tables may be addressed to one of tiie directors of the Anstalt or of one of its departments as detailed below. As fee for a tal)le lOOO K (about 40 L.) will be charged yearly or 100 K (about 4 L.) monthly for all day occupation, or 500 K (about 20 L.) yearly, 50 K (about 2 L.) monthly if it is only intended to l)c utilized half a day (tables need also in this case not to be cleared for the rest of the day).

A limited numi)er of tables is exempt of fees and may be awarded by the directors of the Anstalt or of its departments. The Austrian Ministry of I'^ducation has n^served four tables of which as a rule one is to be awarded in every department.

The Institution comprises the following dei)artments;

Botanv (Directors: W. Figdor' and L. v. Portheim).

Physical Chemistry (Director: W. Pauli; till December 31st 1914).

Physiology (Director: K. Steiniich).

Zoiilogy (Director: H. Przil)ram).

' A separate departraant of plant pliysiology with \V. Figdor as director is prfividcd for.

340

THE MORPHOLOGY OF THE LONG ACCESSORIUS

MUSCLE

J. R. DRIVER AND A. B. DEXISOX Fro7n the Anatomical Laboratory Western Reserve University, Cleveland, Ohio

FOUR FIGURES

In the dissecting-room of this School during the past winter session we have obtained four examples of the long accessorius muscle. We have thought it advisable to place these on record as they form a useful summary of the various origins of this muscle, when present, and of its relation to the accessorius muscle of the sole (M. quadratus plantae).

]Many previous observations on this muscle are to be found, in brief, in the accounts by Le Double (1) and Testut (2). We have, however, endeavored to review the subject afresh, in order to present in concise form the views at present held regarding the origin of this muscle. Our personal investigations have been carried out on twenty-five cadavera, among which only two revealed the presence of the muscle. We have also dissected the myology of the hindlimb in the following animals: Macacus rhesus, Tatusia peba. Alligator mississipiensis.

In this way we hoped to obtain information of assistance in interpreting the muscular arrangement in homo. We do not propose at present to publish the result of these dissections, but simply to extract parts which have direct bearing on the subject imder discussion. We would acknowledge our indebtedness to Dr. T. Wingate Todd for placing the material at our disposal and for assistance throughout the investigation. The specimens of Macacus rhesus were generously presented to the Department by the authorities of the ( "Icni^land Zcn^logical (lanlens.

ui

342 J. H. I)1{I\EH AND A. B. DENI80X

DESCRIPTION

Instances I and J I from Subject 125, mulatto, male, aged forty years

Instance I: Right side (fig. 1). The muscle arose by two heads. The long head possessed a tendinous origin, 3 cm. long, partly from the medial subcutaneous border of the posterior aspect of the tibia and partly from the adjacent fascia covering the M. flexor digit orum longus, 20 cm. above the medial malleolus. The tendon gave place to a flat muscular belly 10 cm. long and 1 cm. broad. The belly passed into a narrow tendon which entered a compartment on the postero-internal aspect of the ankle, medial to that for the ]\I. flexor hallucis longus. The short head possessed an aponeurotic origin 3 cm. broad from the lower and lateral part of the fascia of the leg deep to the tendo calcaneus and also from the medial aspect of the calcaneus in this way being continuous with the medial head of origin of the IVI. quadratus plantae. The short head formed a flat nmscular sheet inserted into the tendon of the long head.

The common tendon, thus constituted, divided to be inserted into the tendons passing to the 3rd and 4th digits from the ]\1. flexor digit orum longus.

Instance II: Left side (fig. 2). Long and short heads of origin were present. Except that their origins were from fascia only, both long and short heads corresponded in all particulars with those on the right side. The origin of the M. quadratus plantae extended higher than normal on the medial aspect of the calcaneus but a hiatus of 5 mm. breadth separated it from the short head of the accessorius longus.

FIk. 1 M. accessorius longus arisiiiR from tibia, fascia covering M. flexor digitorum longus and from fascia of leg deep to tendo calcaneus. The muscle is continuous with the M. quadratus plantae. One-fifth natural size.

Fig. 2 M. accessorius longus arising from fascia only (cf. origins in fig. 1). Short head not continuous with .M. quadratus plantae. One-fifth natural size.

Fig. .3 -M. accessorius longus arising from tibia, fascia superficial to M. soleus, and from fascia of leg deep to ten<lo calcaneus. Short head not continuous with M. rpiadratus plantae. One-fifth natural size.

Fig. 4 M. accessorius longus arising from fascia covering M. flexor digitorum longus and from fibula. Short head of muscle not continuous with M. quadratus plantae. One-fifth natural size.

LONG ACCESSORIUS MUSCLE

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344 .1. H. DHIVKU AND A. H. DENLSON

Instances III and IV from Subject 89, neqro, male, aged twenty years

Instance III: Right side (fig. 3). Tho muscle arose by two lioads. Tho long head was constituted l)y two fibrous slips, the one from the medial margin of the tibia, as in Instance I, the other from the fascia superficial to the M. soleus about 18 cm. abo\'e the medial malleolus. Thus about 2 cm. of the belly of the M. soleus lay between the two slips of origin. The belly of the long head presented a flattened apjiearance ; its length was 12 cm. and its breadth 1 nn. The fibers converged to a slender tendon which passed behind the ankle to the foot, bearing the same relation to the tendon of the ]\I. flexor hallucis longus as in Instance I and receiving in its course some muscular fibers which constituted the short head. These fibers had an aponeurotic origin from the fascia of the lower and lateral part of the leg deep to the tendo calcaneus and about 2 cm. above the medial malleolus.

The short head was not continuous with the origin of the medial head of the M. quaratus plantae. The fibers of the last-mentioned muscle joined the tendon of the M. accessorius longus, and distal to this the composite tendon was inserted into the superficial aspect of the undivided tendinous mass of the M. flexor digit orum longus.

Instance IV: Left side (fig. 4)- Again the muscle presented two heads of origin. The long head arose by aponeurotic fibers, 1.5 cm. in length, from the fascia superficial to the M. flexor digitorum longus, 18 cm. above the medial malleolus. The ))elly assumed a cylindrical ai)pearance, was 8 cm. long and 1 cm. broad, and tenninated in a long slender tendon.

The short head formed a flat fan-shajied muscular sheet 5 cm. l)roa(l at its origin, by muscular fibers directly from the posterior aspect of the fibula, the lower border of the origin being 2 cm. above the groove for the tendons of the MM. peronaei. The fibers of the short head converged to an inscM'tion 3 cm. broad along the slender tendon of the long head. The common tendon, thus formed, was 8 cm. long and partially fused with the common tendinous mass of the M. flexor digitorum longus, from which it separated again and finally fuse<l with the flexor longus tendons

LONG ACCESSORIUS MUSCLE 345

passing to the 2d, 3d and 4th toes. There was a considerable interval between the short head and the medial origin of the M. quadratus plantae.

In both subjects, the MM. plantaris, flexor digitorum longus, and flexor hallucis longus presented no variations worthy of note.

Nerve-swpply

Only in Instance III was it possible to identify the nerve-supply of the muscle. In this case the nerve to the long head was given off from the N. tibiaUs in the upper third of the leg. Unfortunately, at the period of dissection, when the muscles were discovered it was not possible to identify the nerv^e-supply of the M. quaratus plantae. We had thought that these cases might have exhibited a nerve-supply from the medial plantar nerve, as described by Poirier (3), rather than that from the lateral plantar nerve as usually indicated in textbooks.

DISCUSSION

The cases cited above confirm the established teaching that the long accessorius is a vestige of an ancestral muscle of some size, the lowest portion of which alone remains to us as the M. quadratus plantae, and which was, in its development, entirely independent of the M. plantaris.

Typical instances of this independence of the ]\LM. accessorius longus and plantaris ai'e gi\'on in Morrison Watson's description of the muscular anatomy of Proteles and Hyaena (4).

There is evidence to show that the accessorius longus muscle is developed in connection with the M. hallucis longus. An instance of this is given by Parsons in a specimen of (lymnuni rafflesii, in which the flexor accessorius formed a muscular bundle arising from the lateral surface of the calcaneus, crossed the flexor tendons to the toes, from which it received a few fibers and was inserted into the terminal phalanx of the hallux, in this way replacing the flexor hallucis longus (^fibularis) (5).

A less extreme form is illustrated by Young's speci.uen of A'iverra civetta (0). Such an idea is fostered bv the observation

THK AXATOMIC.M. UK.CHUIl, Vol..

346 .1. H. i)iuvp:u and a. h. dknisox

of Schonilnirg in an oarly human onihryo of tlio fusion of tho MM. (juadratus ])lantao and ticxor hallucis longus (7). l^ut against this view must be set the fact that Bardecn did not confirm Schomhurg's observation (8), and also that McMurridi boUeves tho M. accossorius to bo associated more ^particularly with the tibial than with tho fibular flexor (9). Clegenbaur in former years considered tho M. cjuadratus plantae to be a derivative from the muscular mass giving origin to both tibial and fibular flexors (10). Kisler thought the nmscle rather to be associated with the tibialis posterior and to have no direct connection with either flexor (11).

Erna Glaesmer, after her investigation, could come to no conclusion but did not agree with Gogonbaur's interpretation (12). Later she states that she found tho M. ([uadratus plantae arising in some marsupials from tho fibula and not from the calcaneus (13).

The derivation of the muscle cannot therefore be said yet to be settled beyond dispute. But its connection with the flexors of the digits in the leg and with the til)ia and fibula find parallels among lower animals.

So likewise may its connection with the fascia covering the soleus be harmonized wdth the similar occurrences in ]\Ianunalia. For while Parsons found no connection between the 'accessorius' and soleus in Choloepus or Bradypus (14), yet Humphry described tho occurrence in certain instances of a blending between these muscles (ref. 15, p. 177). Here it may be mentioned incidentally that in our specimen of Tatusia poba, we were ah\c to confirm Bland-Sutton's description of the ^l. plantaris (Ui) but failed to find the condition described by ]\lacalister (17).

Our specimens do not justify us, at present, in entering into a discussion of tho variations of insertion of the M. cjuadratus I)lantao. This subject has been recently referred to bj' Miss Glaesmer (13).

With regard to the morjihological variations in the tendons (tf insertion of the tibial and fibular flexors we can add nothing to iho accounts already given by Humphry (15), Keith (IS), ^llaosnior (13) and others.

LONG ACCESSORIUS MUSCLE 347

SUMMARY

1 . Although there is considerable divergence of views regarding the origin of the long accessorius, there is some evidence to show a close association with the M. flexor digitorum longus.

2. The various origins of the crural portion of the ]\I. quadratus plantae find their counterparts in lower animals.

LITERATURE CUIED

(1) Le Double, A. Y. 1897 Traite des variations du systeme musculaire de

rhommc. Paris, T. 2, p. 402.

(2) Testtjt, L. 1884 Les anomalies musculaires chez rhomme. Paris, p. 690.

(3) PoiRiER, P. 1901 Mj'ologie, in Traite d'anatomie humaine. Poirier et

Charpy, 2nd Ed., T. 2, fasc. 1. p. 278.

(4) W.\TSON", M. 1882 On the muscular anatomy of Proteles. Proc. Zool. See,

London, June 20, p. 570. (o) Pahsons, F. G 1898 The limb morphology of Cymnura rafflesii. Jour.

Anat. and Phys., vol. 32, p. 312 (324). (0) Young, A. H. 1879-80 Myology of Viverra civetta. Jour. .\nat. and Phys.,

vol. 14, p. 166.

(7) ScHOMBURG, H. 1900 Entwickelung der .Muskeln und Knoch«n des men schlichen Fusses. Gekronte Prei.ssehrift, Ciiittingen; quoted in ref. 8.

(8) Bardeex, C. R. 1906-7 Development and variation of the nerves and the

musculature of the inferior extremity. Amer. Jour. .Vnat., vol. 6, p. 363.

(9) McMuRRiCH, J. P. 1905 The phylogeny of the crural flexors. .\mer. Jour.

Anat., vol. 4, p. 69.

(10) Gegenb.\ur, C 1892 Lehrhuch der anat. des .Menschen. 5th Kd.. Bd. 1,

pp. 466-7.

(11) EiSLER, P. 1895 Die F^lexores digitorum. Verhandl. der .\nat. Ges. 9te

Vers., p. 144.

(12) Gl.\esmer, Ern.\ 1908 Untersuchung iiber die Flexorengruppe am Unter schenkel und Fuss der Sjiugetiere. Gegenhaur.s Morphol. Jahrh.. Bd. 38. p. 84.

(13) 1910 Die Beugemuskeln am Uiiterschenkel umi Fuss hei den Marsupialia, etc. Gegenhaurs Morphol. Jahrh.. Bd. 41. pp. 214. 323.

(14) WiXDLE, B. C. A., and Parsons, F. G. 1899 On the myology of the Eden tata. Part II. Proc. Zool. Soc. London, December 19.

(15) Humphry, G. M. 1872 Mu.sdes in vertebrate animals. Observations in

myology. Macmillan.

(16) BL.wn-SuTTON, J 1S97 On ligaments. 2nd Ed. Lewis, \^. IS.

(17) M.xcAMSTKH, .\. .\ monograpii on the anatomy of C'hlamydophorus trun ( atus. etc. Trans. Roy. Irish .\cad.. vol. 25, p. 219; quoteil in Ref. 14. (IS) Keith, A. ISO I Notes on a theory to account for the various arrangements of the flexor profundus digitorum in tlu> hand and foot of primates. Jour. An.Ml. :uid Physiol., vol. 2S. p. :V.\/t.

co:\iMrxicATioxs fro:\i scientific institutions

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34.S

A CASE OF ATRESIA AXI IX A HUMAN E:MBRY0 OF

26 MM.

The Anatomicnl Laborntonj of the Universily of Missouri

OXE FIGURE

Among the most common anomalies of the rectum are those of atresia ani, atresia recti, and atresia ani et recti. The first of these is described as being present when an anal opening is lacking. An anal invagination may or may not be present, or the site of the anus may be marked by a surface elevation. In atresia recti simplex the anal opening is present and normally developed, but the upper part of the rectum, failing to unite with the anal portion, ends blindly in the pelvis. In atresia ani et recti, both anal opening and a portion of the ampulla recti are missing. These simple atresiae may be complicated by the additional anomalous conditions of fistulae into the urethra, bladder, vagina, vulva, or through the scrotum and perineum.

Such anomalies of the rectum, which are usually detected at the time of birth or shortly afterward, have aroused considerable interest, and various theories have arisen as to their probable origin. Among those who have studied the causes of rectal anomalies should be mentioned the names of Rotter ('03) and Jones ('04).

However correct any of the theories regarding the formation of these atresiae may be, before they can be definitely accepted, they demand not only a correct knowledge of the nonnal ilevelopment of of these parts, but direct evidence concerning the time and manner of deviation from the niM-mal. It is ])ecause of this that the present atresia, fountl at a comiiarati\ely early stage of the emhryo, is described. Althougli the author knows of no other case of this kind found in an eini)ryo, the observati(Mi which Keibel

34'.)

3oU

made on an enil)ryo of 11.5 mm. should ho mentioned. He found that the lumen of the rectum in its lower part had become occhided at two small places. The observation, however, offers no evidence, direct or indirect, that this would develop into a case of atresia. It seems probable that the lumen might have again opened up, for in corresponding stages of pig and rabbit embryos (Lewis '03) and of chick embryos (Minot '00), where there is normally an epithelial occlusion of the rectum, such reopening occurs. It should also be recalled that epithelial occlusion occurs normally in the developing duodenum (Tandler '00, Johnson '10).

Civ

bul.a.

Fi^. 1 CJraphic rcconstnu-tion of tho pelvis of :i liuinun ciiihiyo of '_'(> iiiiii. (H 99). all., allantoi.s; amp.rcc, aini)ulla recti; hul.a., blindly ondinti hulhus analis; d, Miillerian and Wolffian ducts; CI. antl (\I\', first and fourth coccyncal vertebrae; <S./, first sacral vertebra.

The case of atresia under cousidcM-ation (see accompanying figure) was found in Embryo H 99 of IVof. C M. Jackson's collection, the crown-rump length of which is 20 nmi. The sections were cut transversely to tho long axis of the embryo, hence the plane of sectioning through the lower part of the rectum is longitudinal. The upper part of the rectum is apparently normal. Its epithelial tul)e has a transverse dianteter of 0.23 mm. and is composed of two to three layers of cells. More caudally the rectal tube expands, forming what has been termed in a former paper (Johnson '14) the bulbus analis. Tliis has a transverse diameter of 0.29 nmi. at its widest place and its ej)itheliinn is of about

ATRESIA ANI IN A HUMAX EMBRYO 351

the same thickness. A single deep infohhng extends itself along the ventral wall of the tube. The epithelium of the upper part of the bulbus analis is regular, its nuclei are closely packed and distinct, but cell boundaries are not distinguishable. At about the middle of the bulbus analis the epithelium becomes broken up, and from this point caudally becomes more and more irregular. In this region the nuclei are more scattered and in places less sharply outlined than above. The lumen becomes gradually filled up with broken-of^ pieces of the epithelium, and lower down becomes lost in a mass of epithelial debris. The lower portion of the bulbus analis is smaller in size, and finally disappears from view altogether. The last remnants are seen as a few nuclei scattered about in the mesenchyma. The epidermis of the anal region is found about 0.55 mm. caudad to these last remnants. An anal invagination is present but it is very shallow.

Surrounding the epithelial tube throughout its whole length is mesenchyma. In the upper part of the bulbus analis this lies close to the epithelium, but in the lower part, where the epithelium is broken down, the mesench^^na is separated from it by a distinct shrinkage space. At the termination of the epithelium the shrinkage space again disappears. Between the lower end of the rectum and the anal invagination, the mesench^^na shows no special features. It is possible that some of the nuclei seen in the mesenchyma of this region belong to the epithelium. Init this point is not determinable.

The inner circular and the outer longitudinal layers of the muscularis are distinct. They terminate a short distance above the last renmants of the epithelium. As has been formerly shown (Johnson '14) the circular muscle coat terminates normall\- at the constriction between the bulbus analis and the bulbus terminalis. This affords a moans of d(>tonnining that the last })ortions of tlie (^pitlu^lium ro])rescMit a i):irt of the bull>us terminalis.

In front or ventral to the rectum is seen the urogenital sinus, which at this stage is (juite widely separated fron\ the rectal tube. Opening into it are seen the luiited MuUerian ducts and on either side, the two \\'oini:ni ihicts. ahhough thcMr epithelia are somewhat l)roken up and in(\!j;iilar. Tli(> uitS»M"s do not join t!ie uro

352 FHANKLIX PARADISE JOHNSON

genital sinus Init ond blindly, their ojiitholium being broken down in a similar manner to that of the rectmii.

The results of my work on the development of the normal rectum have shown that the bulbus analis and the bulbus terminalis go into the formation of the zona columnaris and zona intermedia of the ])ars analis recti respectively. Since in this anomalous embryo the epithelium of the rectum teniiinates in the region of the bulbus tenninalis, it is evident that the missing portion of the rectal tube represents what would have normally been the zona intennedia. The anomaly should, therefore, be classified as a case of atresia ani simplex. However, owing to the pecuhar disposition of the ureters, it is douVitful whether it would have retained its simple relations, had the embryo lived longer.

Regarding the cause of this anomaly Uttle can be definitely said. It is doubtful whether the anal membrane is in any way concerned. In an examination of 19 embryos of 15.5 mm. and over, Keibel and Elze ('08) show that in stages of 15.5, 16, 17, 18, 18, 18.5, 19.5, 20, 20, 20, 20, 20.5, 22, 22.5, 24, 24, 26 and 26 mm. the anal membrane was present and the anal passage closed to the outside, while in only one case (22.5 mm.) was the passage open. Broman ('11) states that an anal opening is not effected until the embryo is about 33 mm. in length. The results of my own work show that the anal membrane is present in embryos of 17, 19 and 22.8 nmi. and has disappeared in those of 16, 29, 30, 30 and 31 mm. and above. From these observations it will be seen that usually at 26 mm. the anal membrane occludes the anal passage, so that the above anomaly cannot be explained by a failure of the anal meml)rane to break down normally. Constriction and a subsequent breaking apart of the epithelial cord at this place must have occurred.

ATRESIA AXI IX A HUMAN EMBRYO 353

BIBLIOGRAPHY

Bromax, I. 1911 XormaleundabnormeEntwicklungdesMenschen. Wiesbaden.

JoHXSOX, F. P. 1910 The development of the mucous membrane of the esophagus, stomaeh and small intestines of the human embryo. Am. Jour. Anat., vol. 10, pp. 521-561.

1914 The development of the rectum in the human embrj-o. Am. Jour. Anat., vol. 16, pp. 1-58.

JoxES, F. \V. 1904 The nature of the malformations of the rectum and urogenital passages. Brit. Med. Jour., vol. 2, pp. 1630-1634.

Keibel, Fr., and Elze, C. 1908 Xormentafel zur Entwicklelungsgeschichte des Menschen. Jena.

Lewi.s, F. T. 1903 The gross anatomy of a 12 mm. pig. Am. Jour. Anat., vol. 2, pp. 211-225.

MiNOT, C. S. 1900 On the solid stage of the large intestine in the chick. Jour. Boston Soc. Med. Sci., vol. 4, pp. 153-164.

Rotter, J. 1903 Die Krankheiten des Mastdarms und des Afters; in the Handbuch der pracktischen Chirurgie by Bergmann et al.

Taxdler, J. 1900 Zur Entwickelungsgeschichte des Menschlichen Duodenum in friihen Embryonalstadien. Morph. Jahrb.. Bd. 29, pp. 187-216.

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354

CYCLOPIA IX MAMMALS

F. E. CHIDESTER

Zoological Lahuratory, Rutgers College

TWELVE FIGURES

Among the mammals, cj'clopia has been reported in man, monkey, cow, sheep, goat, pig, stiig, horse, dog, eat, rabbit. In this paper is recorded a monster of the cyclopean order in the rat. Cyclopia has also been recorded in birds — in the chick, goose, dove, duck; and in fish — in the salmon, skate, trout. Cyclopean monsters have been produced experimentally in the chick, frog, salamander, fish and flatworm.

In many of the cyclopean monsters there are no abnormalities other than those of the head. In some, the mouth is normal. The oldest Cyclops in man, recorded by ^'alenti (,'94), lived 73 hours. In the skate descril)ed by Paolucci (74), the age was several years, since the fish was H feet long and 2| feet wide. The fish seemed to l)e able to procure its food readily. Yung ('01) reports a case of monophthalmia in a rainbow trout. The eye was on the left and apparently normal. The fish lived 22 months, feeding on Tubifex; movement wiis in circles. Stockard ('10) succeeded in keeping magnesium em})ryos for 1 month in aquaria. Many of the human cycloi:>s breathe in a shallow way through the mouth, for only a few minutes.

This paper is a study of three specimens of the mannnalian cyclops: (1) Cyclopean rat: Two monsters appeared in the mother's first litter, of six rats. One sju'cimen was a case of anterior hydrenceplialocele and will be described elsewhere. The other was a case of anophthalmia cyclopica. For these two specimens and two normal members of the same litter, I am indebted to Dr. Newton Miller. (2) Cyclopean pig witli otocephalus: This rare specimen was loaned to me by Prof. F. H. Lillie of the rniversity of Chicago. The specimen came from the Chicago stockyards. (3) Human cydojiean l>rain: This specimen wiis sent me by Prof. H. 11. Wilder of Smith College, who h:us already tlescrilH'd the external anatomy and the structure of tlie eyeball. The specimen was No. ODoli of The Wistar Institute Collection. 1 am indebted to Dr. (ireenman of The Wistiir Institute and to Professor Wilder for the privilege of studying the brain and for information regaiding the fetus.

350

F. E. CHIDESTER

Kxtcnial (ippcorance of the specimens

Tlic rat \v:ij? sligiitJy smaller than the two controls, measuring only 30 mm. while they were each about 40 mm. long. The specimen was a female and except for the absence of eyelids and eyeballs, seemed to be normal.

The Cyclopean otocephalic pig (fig. 1) was a female and measured 165 mm. C, R. Tlie bitemporal diameter of the head was 45 mm. There was no proboscis and no eyeball. In the middle of the forehead there were three eyelids; the upper one was composed of the two fused

Fig. 1 Cyclopcim Dtocophalic i)ig.

upper lids; under the eyelids, which together were 5 mm. in diameter, was a pit 1 mm. in diameter, which might possibly ])e interpreted as the beginning of the invagination of the ectoderm to form a lens.

The human cyclops, from whicli I obtained the brain only, was a male, with nasal proi)oscis about Ij inches long, and a double eye of the hour-glass type. Professor ^^'ilder has described the specimen (Wilder '08j as a "typical human cyclojis, identical in general appearance with the specimen photographed by Hirst and Piersol, vol. 3, plate 31."

CYCLOPIA IN MAMMALS

357

COMPARATIVE STUDY OF THE SPECLMEXS The rat

The head of the rat was dissected under a Zeiss binocular and the brain was exposed and studied in situ, then removed, drawn in several positions, and finally eml^eddcd in paraffin and sectioned. The sections were from 15 to 20 micra thick and the stains used were congo red and hematoxylin-eosin.

Skull. The skull bones were a little thicker than in the controls, but were not seriously displaced. The frontals were fused and no trace of the nasals was found.

Ant. ves.

Cblm.

Fig. 2 Dorsal view of the brain of an anophthalniic rat. Ant. ns., anterior lobe of cerebral vesicle; C6/m., cerebellum; Lat. res., lateral lobe of cerebral vesifle; Th., thalamus.

Fig. 3 Lateral view of the brain of the anophtlialmic rat.

Brain and cerebral nerves {jigs. 2 and S). A study of the brain in gross show(>(l that there wer(> three cerebral vesicles, one being slightly anterior to the two painnl lateral vesicles. ThiMV was no external incUcation of hydrocepiialus. The cerebellum was pushed Ivu-k to a ventral position and tlie hemispluM-es wer(> somewhat separated trom the vermis. The cerebral peduncles were absent; tiie cranial nerves anterior to the fourth were absent; the thalamus was well developetl anil the fourth ventricle was normal; the corpt>ra (puulrigemina were a]i]x\rently normal. On comparison witli the normal l>rain, it was found that tl\e brain of the monster measured 5 nun. in length from the anterior end

358

F. E. CHIDESTER

of tlu' ccrcln-al vesicle to tlic cervical flexure, while the coiitrnl l)raiii measured 9 mm. in a correspoiuliuf!; region; the control brain measured 7 mm. through the cerebral hemi.spheres. while the brain of the anophthalmic rat measured but 2 mm. through the lateral vesicles.

The study of s(>rial sections showed the apparent absence of the corpus callosum. The ventricles, however, showed only a slight enlargement, without a marked hydrocephalus; the hypoi^hysis was present, but the epiphysis was absent, or if present it was not discovered.

Fig. 4 Skull of the cycloiM'an otocephalic piji. Fr., fused froutals; Ocr., occipital; Pdr.. ])arietal; .S.. oyo-socket.

Fig. 5 Fri)iit view of the skull of the pig, with the skin rolled down to the mouth and the eye-muscles cut transversely. Ant. ch., anterior chamber of the eye; Fr., cut frontals; //., glandular sac; .1/., cut eye-muscles; -S., eye-socket; iS/,-., skin rolled down to oxjxjse eye-socket.

The pig

In this extremely rare monstrosity, the ears and mouth were fused, with a single ojx'ning but .") mm. in diameter; no ])roboscis was present. It is interesting to note that the only case of a human fetus with the l)rol)oscis below the eye, described by Allan ('48), was a case of cyclopean otocephalus.

Skull (Jig. 4)- Since it was desired that the .specimen be as little mutilated as possible, not all th(» bones of the skull were examined. The frontals were fused, the parietals and the occii^ital were in about normal ])osition, but the ]iarietals extended anteriorly for some distance and joined the frontals in the regioii ordinarily occu|Med by the nasals. The lower jaw was absent.

Eye-socket and eye-muiicleii {Jig. 5). After removing the skull-cap, an attempt was made to ex])ose the face (Unm to the mouth, without

CYCLOPIA I.\ MAMMALS

359

injuring the specimen for museum purposes. The skin was carefully rolled down to the mouth, a transverse cut being made through the mass of eye-muscles; figure 5 shows the regitjn exposed. There was no indication of a lens or eyeball; a glandular sac was present just above the attachment of the eye-muscles to the base of the eye-socket. This might possibly be interpreted as a portion of the h\7)ophysis. The little pit under the eyelids (fig. 1) was examined from the rear but no

Fig. () Brain of tiic fyclopi-aii i)i^t in situ. ('«;/•/.. iiis|)laco(i na.sal cartilage; Cer., thin cerebrum; Cbhn., cerehollutn: /•'. cir., falx ccrcliri: d.. cartilage covered glandular mass; N., eve-socket.

lens tissue was found. .\ ciuimlier of considerable d(>pth (1\ mm.) was l^resent in the midst of the eye-iiuLscle mass at its point of attachment to the skin.

Hrnin. A cut was made through the upper tiurd of the pariet4\ls and the fused frontals and tiie i)raiu was ex])osed. The ilura was very thin and closely ai)post>d to th*' cranium exce]>t at two points, one being the location of the rudimentary falx cerel>ri an«l the other, the somewhat thickened tentorium ceri'ln'lli. When first viewing the brain in situ (fig. 0), (me was imnuHliately struck with the thinness of the cerebrum.

360

F. E. CHIDESTER

tho cartilaginous mass cxtciKling from the thalamic region do^^^l over the cerel>rmn to the sides of the eye-socket, ami the peculiar cui>sliaped form of the dorsally extending cerelx'Umn. The pia antl the arachnoid closely invested the brain structures ])resent. Although some arachnoid was closely apposed to the dura, it was judged that a distension of the subdural space by escaped cerebro-spinal fluid had taken place.

Lateral view of the head. Figure 7, a diagrammatic representation of the head of the pig, shows the relative thinness of the cere])rum, the size of the cavity dorsal to the brain, and the large size of the coUiculi. The first three pairs of cerebral nerves were absent, but the others

Cbim.

Fig. 7 Diap;raiiun:itic side view of tho head of the pig. Cblm., cerebclUim; Coll. .sup., colliculus sui)eri()r; Coll. inf., collicuhis inferior; E., ear.

were present, though smaller than in the controls. A representation of the attachment of the falx cerebri has been omitted from the diagram.

Posterior view of the brain. In figure 8, drawn from a photograph, the thalamic mass has been elevated and the large superior and inferior coUiculi are plainly seen. The third ventricle was found to be continuous with the fourth ventricle, with no notic(>able constriction to form an iter. The anterior medullary velum was i^resent and very thick; the misshapen cerel)ellum was relatively large.

Mesial aspect of the brain of the pig. Before a mesial section of the brain was made, the thin cerebrum was detached; sections were made through the cerebral tissue and particular care was taken in sectioning the cartilage in the region marked (1 in figure G. The lump sectioned

CYCLOPIA IX MAMMALS

361

readily and proved to consist of glands covered by a thick layer of cartilage. It is not impossible that the epiphysis was retarded in its development and forced down by a mass of overgrowing cartilage. The mesial section of the pig's brain (fig. 9) serves to show more clearljthe relation between the third and fourth ventricles and also indicates the retardation of the massa intermedia. The thalamic mass was fused and the anterior tubercles were thick and extended only to a point just ventral to the epiphj'seal mass.

Cer.

Hem. cbl.

Vent. IV.

Fus. vent. y^_

Fig. 8 Posterior view of the brain of the pig. Coll. sup., coUirulus superior; Coll. inf., colUculus inferior; Hem. cbl., Heniisphaerium cerebelli; Th., thalamic mass; Ve7i(. Ill, vcntriculus tertius; Venl. IV, ventriculus quartus.

Fig. 9 Mesial aspect of the brain of the pig. Cblm., cerebellum; Cer., point at which thin cerebrum was detached; Coll., colliculi; Fm^. rent., fused ventricles with medullary velum removed; Th., thalamic mass.

Micro.'^copicnl .s7(/r/)/ of ."iedions throiujh (he cord. The medulla and a portion of the cord were removed prior to the cutting of the mesial section and the block was (Mnbedded in parathn; sections M micra thick wen^ made and stained in liematoxylin-cosin. Ti\e coriuia were well marlanl aud tlie dorsal cohnnns were jiarticularly well stvn. In an anophthalmic pig descrii)ed liy Duckworth ('1)8) the Wcigcrt method showed the tracts as clearly as in tiie control. Duckworth tiiinks this a strong sujiport for the tiieory of the laying down of ti\e pyramidal tracts in situ. In many cases of cyclopia recordetl in the literature, the descending tracts of the cord are absent. Let us l)rieth- consider l^uckwortli's specimen.

THE AN.VT<1MICAL UKCOI(I), VOL. 8. NO. 6

302 F. E. CHIDESTER

Duckworth's case of otocephalic anophth<ilini<i. In tliis specimen we find a mucli more extromo otocoplialus tlum in the one which we liave just noted. The pig was devoid of eyes Ijut iiad ears separated. The brain was perfectly .symmetrical, consisting of medulla, pons and cerebellum, with the structures connected witii those parts. The cerebellum capped the pons in a manner similar to the brain just described.

The human cy clops

In none of the cases of true cyclopia with a nasal proboscis, has there been found evidence of innervation of the proboscis itself. Dr. Wilder did not study the pro})oscis, but he made a thorough examination of the e.yeball of the specimen from which I secured the brain. We may quote briefly from Wilder's description.

Eyeball and eye-muscles

"In the eye])all itself, this specimen is decidedl}' douljle. The palpebral opening is evident and oval in shape. At the exact center of the lower margin there is a single median caruncula, with a punctum lacrymale upon either side of it on each lid component. ( Corresponding to the shape of the jialpebral opening of the eyeball is a flattened piriform organ. The relationships and positions of the irides and pupils could not he made out, but they seem to have been turned upwards so that the optical axes would strike above the palpebral opening. Within, the eyeball is incompletely divided into two compartments by a median partition that reaches from the front wall half way back. Each compartment is furnished with a well developed lens, but that of the right side is slightly smaller than the other and not perfect in shape. Back of the lens, each compartment is nearly filled with a large mass of fine connective tissue, of almost the consistency of cartilage, which bears the lens in an anterior cup-shaped depression. This is undoubtedly the vitreous humor." (Wilder '08.)

The optic nerve was single and the eye-muscles were symmetrically disposed, showing a complete bilaterality, but the amount of abnormality was not determined. It has been found by other investigators that in c^'dopean mammals, the internal recti muscles are generally absent; the obliques nuiy be present and the external recti are generally present.

liuuian brain (jigs. U) and 11). The brain was about one-fifth smaller than the control, measuring 5.25 cm. across the widest part of the cerebrum and 7 cm. in length, measured from the most anterior part of the cerebrum to the most posterior part of the cereliellum. The cerel)rum was practically smooth, and the membranes were tightly adherent to the single vesicle. There was no falx cerebri, but the tentorium cerebelli was present. The left side of the cerebral vesicle projected slightly fartiier jjosteriorly than the right side. The cere

CYCLOPIA IX MAMMALS

363

brum did not overtop the cerebellum but was contiguous to it at the elongation of the cerebrum on the left side. The single cerebral vesicle was thin, varying from 5 to 10 mm. in thickness, and was hj^drocephaUc. The cavity was formed by the fusion of the fifth and lateral ventricles. Into the cavity through the posterior opening, 3.5 mm. in diameter, projected the anterior tubercle of the fused optic thalami. The chorioid plexuses of the lateral ventricles svere well developed but displaced

III. Tub. ant.

Vent. III. Coll. sup.

Vi^. 10 Dorsal view of the brain of a human ryelop.s with hour-glass eye, showine; the cavity of the cerebral vesicle. PI. Int., plexus chorioideus ventriculi lateralis; PI. Ill, plexus chorioideus ventriculi tertii. Coll. xup., coUiculus superior; Tub. anl., tuberculum anterius thalami; Vfut.. cavity of the cerebral vesicle; Vent. in. Mind third ventricle.

backwards. Tiu- lateral i>lexuses lay along the margin of the cavity. The fourth ventricle was covered by the thick anterior medullary v(^lum, and tlie chorioid jilexus of tlie fourth ventricle seemed well developed. The cerebellar peduncles were normal.

Ventral aspect {fig. 11). At the anterior end of the cerebral vesicle two depre.^^sions faintly marked it into three lobes on the ventnil side. The hypophysis was present antl the manunillary Ixxlies appeared,

304

F. E. CHIDESTER

partly fused. The eeiei)ral peduncles were rather hu'ge; the optic thaiami were present and of normal size, but the geniculate bodies were absent. The pons, the medulla and the crura were present and well formed. The large single optic nerve was found but there was no indication of an olfactory. All the other cerebral nerves except the

I'"ig. 11. Ventral view of the liuinan brain. Ant. I., anterior lol)e of the cerebral vesicle; Bl. v., blood vessel; .V. //, nervus opticus; A'. ///, nervus oculoniotorius; P. pons.

Fig. 12 Mesial aspect of the brain of the human cyclops. Aq. cer., aqueductus cerebri; Bl. v., blood vessel; Cblm., cerebellum; M., medulla; P., pons; PI. hit., plexus chorioideus ventriculi lateralis; PI. Ill, plexus chorioideus ventriculi tertius; Tub. ant., tuberculum anterius thalami; Vent, cer., cavity of the cerebral vesicle; Vent. Ill, aperture of the blind third ventricle; note that the aqueductus cerebri does not connect with the third ventricle; Vent. IV, ventriculus quartus.

eleventh were traced. There is no reason to suppose that the eleventh was not present.

Mediayi flection (fig. 12). A mesial section of the human cyclops brain ser\^ed to show the sejiaration of the aqueductus cerebri from the third ventricle, and the absence of fornix, callosum and epiphysis. The fourth ventricle was apparently normal; the olivary bodies seemed well developed; the coUiculi were normal in size and appearance.

CYCLOPIA IN MAMMALS 365

SLM.MARY

This paper is based on the study of three cases of mammuiian cyclopia, the first being a case of anophtiialmia cyclopica in the gray rat; the second a casv of anophthalmia cyclopica with otocepludus. in the pig; and the third a case of cyclopia with hour-glass eye, in man.

The rat had no external or internal indications of an eye; the pig had no eyeball nor lens, init had three lids, the two upper ones being fused almost completely; the human fetus, the brain of which was studied by the writer, had a typical hour-glass eye with two well-formed lenses. Neither the pig nor the rat had a proboscis, while the human cyclops had a well-developed single proV)oscis above the fused eyes.

The brains of the specimens fall readily into a series, with the brain of the rat tlie lowest in the scale, the brain of the pig next and the human brain the highest in development. The l)rain of the rat was not hydrocephahc and the cere]>rum was represented by three vesicles. The cerebellum was ventral to the pons. The hypophysis was present, the epiphysis was absent and the fourth ventricle normal, no corpus callosum was present.

The brain of the pig was markedly hydrocephalic, the hydrocephalus being external and the cerebrum reduced to a thin sheet of ti.ssue. The pons and medulla were normal, while the cerebellum formed a cup for the rest of tlu^ V)rain. The colliculi were normal in size and position and the brain was bilaterally symmetrical except in the posterior region of the pons, l^etween the anterior end of the pons and the l)ack of the eye-socket extended two cartilaginous masses, interpreted as displaced nasal cartilages, which neither grew to form a snout nor stimulated the growth of a proboscis.

The human brain was a case of internal hydrocephalus in which the cerebrum was developed rather more than in the case of the pig. The cerebral mass was faintly marked into three lobes. The hyjiophysis was present and the mannnillarv bodies were jiartly fused. The pons anil medulla were of normal size and configuration. A single opticnerve was jiresent. The anterior tubercles of the optic thalami projected into the cavity of the cerebral vesicle.

LITERATURE CWKD

Allan, R. 1S4S Dissection (if a liuinan astoiuatous cyclops. Lam-ot, vol. 1. p. 227.

Ballantynk, J. W . 1002 Tho fetus. Manual of antonalal patholoiiy. Kdinburgli.

1004. 'i'ho emhrvo. Manual of anttMiatal pathology. Edinburgh.

Bl.vck, D. 1). 1013 The contral ncM'Vous systtMU in a case of cyclopia in homo. Jour. Conip. \our.. vol. 2)^. pp. 103 2 ")7.

'MSi) F. E. CHIDESTER

DrcKwouTii, \\ . L. H. l'JU8 Destriptiun uf u niiciocephalous new-born pig in which the face and fore-parts of the brain were undeveloped and the bucco-pharyngeal membrane remained imperforate. Proc. Camb. Phil. Soc, vol. 14, pp. 447-456.

X.\E(;eli, O. 1897 Ueber eine neue mit Cyklopie verkniipfte Missljildung des Centralnervensystems. Archiv f. Entw. Mech., Bd. 5, H. 1, pp. 169218.

P.xoLrcci, L. 1S74 Sopra una forma monstruosa della Myliobatus noctula. Atti. (lella Soc. Itai. di Sc, T. 17, pp. 60-63.

Puis.\Lix, C. 1889 Monstres Cyclopes. Jour. d. I'Anat. et di- la Physiol., T. 25, pp. 67-105.

Stock.\rd, C. R. 1907 The artificial production of a single median cjclonean eye in the fish embryo by means of sea water solutions of MgCUArchiv f. Entw. Mech., Bd. 23, pp. 249-258.

1908 The development of artificially produced cyclopean fish, "the magnesium embryo." Journ. Exp. Zool., vol. 6.

1910 The influence of alcohol and other anesthetics on embryonic development. Am. Jour. Anat., vol. 10, pp. 369-392.

T.\RUFFi, C, and Vogt, H. 1894 Cyclops dirrhiiuis. Mem. d. Roy. Acad. d. Sc. d. Istut. d. Bologna, T. 8, p. 540.

Valenti, G. 1894 Sopra una caso di ciclopiu nell. uomo uotevale per alcune anomalie concomitanti. Annali della Univ. di Perugia, N. S., T. 7.

Wilder, H. H. 1908 The morphology of cosmobia; speculations concerning the significance of certain types of monsters. Am. Jour. Anat., vol. 8, pp. 355-440.

Wyman, J. 1859 Cycl()|)ism in a pig. Boston Med. and Surg. Jour., vol. 59, p. 121.

Yu.vc;, E. 1901 Monstrosity in a trout. Rev. Suisse Zool., T. 9, pp. 307-313.

TWINS IN FISH, ONE WITH A CYCLOPIC DEFORMITY

F. E. CHIDESTER

Zoological Laboratory, Rutgers College

FOUR FIGURES

Many cases of twins and double monsters in fish have been recorded but no case of apparent modification of structure by chemical means in one of twin fishes has been mentioned. In this paper it is my purpose to record a case of cyclopie deformity in one of twin Funduli, a case of double monster in Fundulus and a case of twins in Squalus acanthias.

During the summer of 1909, while occupying a research table from the Department of Zoology of the University of Chicago, at the Marine Biological Laboratory, I was engaged in imtting up material for the study of the nervous systems of cyclopie and anophthalmic Funduli. In one of the experiments with ether, I chanced to secure twin Funduli. one of which was apparently cj'clopic.

In the experiment, eggs from several females were fertilized by the sperm from one male and when the majority of the eggs were at the two-cell stage, a 3 per cent solution of ether in 100 cc. of sea-water was added to the eggs, which nearh' covered the bottoms of two fingerbowls. The finger-bowls were then covered with glass plates to prevent too rapid evaporation. The extremely toxic action of the ether was so noticeable that at one time the separation of the living from the dead eggs was considered useless. However, two days after the experiment was started, the water was changed for fresh sea-water antl a few of the dead eggs were removed. Three da\'s from the beginning of the experiment the dead eggs were jjicked out and the remaining few were placed in fresh sea-water. The living eggs numbereil 21o and the uncounted dead eggs numbered al)out ()00. At the end of six days' time, the normal eml)ryos were s<^parated from tiic abnormal.

In the first lot, there were 2 cycloi)s, I jiair of twins and 110 normal. In the second lot, tliere were 9 typical cydops and 7S normal. The twin Funduli were most cU)sely observed and were killed and preserved on the sixteenth day only because it was evident that they were about to die. Figures 1 and 2 show the defect that appeared in one of the specimens. The cydops was the smaller of the two; tiie eye on the right side was api)arently lacking. The heart-beat of the cyclops on the fifte(>nt.h day was 90 per minute, while that of the normal twin w;is 110. The smaller embryo was only about one-eighth smaller than the controls

Ml

368

F. E. CHIDESTER

at this time. ??ections of the cj'clopic twin showed that it was^^not a case of true cyclopia, but hke many vvliich appear in experiments with anestlietics (Stockard '10), it had a minute, deeply-buried lens in the position normally occupied by the optic vesicle.

In 1910 Mr. F. J. Kelly presented me with a double-headed specimen of Fundulus. The monster appeared in a lot of eggs numbering about 300. As in my experiment, the preponderatingly large number of

Fig. 1 Fig. 2 Stockard) Fig. 3

Camera sketch of the twins. X 8. Another view of the twin Fvinduli.

Double-headed Fundulus. X 8.

(Camera sketch X 8 by C. R.

dead eggs caused Mr. Kelly to consider not picking out the few living embryos. The eggs developed in 50 cc. of sea-water, fertilization having been delayed for half-an-hour in the case of about two dozen of the eggs (fig. 3).

In one of his earlier papers, Stockard mentions a case of incomplete diprosopus with three eyes and an additional lens (Stockard '00), but does not mention any factors other than anesthetic. Mr. Kelly's specimen showed four well-developed eyes. Sections were made and the specimen was found to be like many other doul)le-headed monsters (Oemmill '00, '03). It possessed two mouths and throats, but only one heart, and had twin brains united at the optic lobes.

TWINS IX FISH

369

Fig. 4 Twin dogfish. X h.

Through the kindness of ^Ir. George M. Gray of the Marine Biological Laboratory, 1 had the privilege of examining and photographing twin dogfish which he secured just l^efore they would normally have been extruded. The specimens were males and were apparently normal, with a single yolk sac. Measurements showed that the twin.s'were truly 'identical.'

LITERATURE CITED

Gemmill, J. F. 1900 The anatomy of syminotriral double monstrosities in the

trout. Proc. Roy. Soc, vol. 68, no. 444.

1903 A contribution to the study of double monstrosities in fishes.

Proc. Zool. Soc., London, vol. 2, pp. 4-21. Stockard, C. R. 1909 The development of artificially produced cyclopean

fish, "the magnesium embryo." Jour. Exp. Zool., vol. 6, pp. 2S5-33S.

1910 The influence of alcohol and other anesthetics on embryonic

development. Am. Jour. .\nat., vol. 10, pp. 369-392.

^11

ox THE VASC'ULARIZATIOX OF THE SPINAL CORD OF THE PIG

E. R. HOSKINS From the Inslilule of Anatomy, University of Minnesota

FIVE FIGURES

HISTORICAL

Until 1904 little work had been done upon the development of the blood-vessels of the spinal cord, except that of His ( '86) who undertook to follow the growth of these vessels in human embryos. The observations of this author have been largeh- disputed by Sterzi ( '04) and Evans ( '09), the two writers who have done most of the work in this field.

By far the most comprehensive publication upon the development of the vessels of the spinal cord is that of Sterzi ('04j. In this he discusses the development of the vessels in the five higher classes of vertebrates. As a tj'pe of the ^Mammalia he uses the sheep. He brings out the following points:

The blood-vessels first approach the cord at the ventro-lateral border and spread over the ventral surface, then over the lateral, and finally over the dorsal surface. Each vertebro-medullary artery as it approaches the cord divides into a ventral and a dorsal ramus, the ventral and dorsal radical arteries. The ventral radicals from either side halt at the lateral edges of the floor-plate, and each divides into a cranial and a caudal branch. These anastomose with those of adjacent segments and form two longitudinal arteries on tlu^ ventral surface of the cord, the "tractus arteriosus primitivus. " Later they send out medial rami and through these become connected. Still later, alternate parts of the two tracts degenerate while other parts continue to develop. These enlarged segments are joined together through their medial rami and form a single ventral artery which Sterzi terms the tractus arteriosus ventralis, and which is tiie anterior spinal artery

371

THE ANATOMICAL RECOBD. VOL. S, NO. 7 JULY. I'JU

372 E. K. HOSKINS

of most authors. From the primitive tract, dorsal rami enter the substance of the cord. Each dorsal ramus forms a loop and gives rise to a vein, which courses ventrally and enters the primitive sulcus. Later other vessels extend into the cord from the lateral, and still later from the dorsal surface.

The dorsal radical arteries, where they di\ide, form many small longitudinal capillaries just ventral to the i:)()ints of emergence of the tlorsal ner\'e roots. From these capillaries there is formed later a longitudinal artery on either side of the cord, in this plane (tractus arteriosus lateralis). The vessels entering the cord are f'rst solid and later become hollow.

Evans ( '09) shows by a series of injected pigs the early de\'elopment of anterior spinal artery In his figures the mid-ventral surface of the cord is shown to be free from vessels until the embryos are 8.5 mm. in length, and the mid-posterior surface until after the pigs are between 8 and 10.5 mm. in length. He does not take uj) the later stages,

MATERIAL AND MKTIIODS

For a study of this nature, injected embryos are indispensable, and they are best injected while living, with warm india ink diluted one-half with weak ammonia water. It is pi-ef(M'al)le to inject through the umbilical arter}^ rather than through the umbilical vein, because the arteries are less readily ruptured and because the route between them and the vessels of the spinal cord is much more direct.

Eml)ryos used for thin serial sections are better if they are congested instead of being injected. This congestion is accomplished as follows: The uml)ilical cord is tied while the embryo is yet living, thus causing an increase in the blood pressure in the aorta. One of the most direct outlets for this increased pressure is the system of segmental arteries, and through these the bloodvessels in and around the spinal cord soon l)ecome engorged. When this condition is i-eached, as evidenced by the increased redness of the dorsal region of the embryo, the li\'e embryo is droi;)]Ded into a fixing fluid which penetrates rapidl}^ so that the capillaries are fixed before they collapse. Bouin's picro-formo-acetic mix

VASCULARIZATION OF THE SPINAL CORD 373

ture serves this purpose very well. P^mbryos treated in this manner show the smaller vessels much more plainly than those fixed in the usual way.

Small injected embryos which have been cleared in oil may be dissected under the binocular microscope and all the external vessels of the cord demonstrated, or they may be sectioned in celloidin to show the internal vessels.

From pigs larger than 25 or 30 mm. the cord with its membranes may be dissected out and embedded in celloidin and cleared, or for temporary preparations may be cleared directly.

Serial sections of the cleared embryo or spinal cord can be kept permanently between two pieces of paper soaked in oil, or can be transferred to slides and mounted in damar gum. To make slide preparations, the sections are cut in oil and placed on a piece of thin paper in the same order they are to have on the slide. Another piece of oiled paper is laid down upon them and the whole inverted. The first paper is now peeled off and the other paper holding the sections is inverted upon the slide. This paper is then peeled off, leaving the sections on the slide in their proper order. They may then be washed carefully with xylol, and covered.

There are several advantages in a study of this kind, in section ing celloidin-emljcddcd embryos free-hand in oil. The cord can be turned so that sections may be cut through any plane. Sectioning is done more rapidly than with a microtome, and much time is saved. It is easy to make transverse, sagittal and frontal sections from any region of tlie same cord. The block can be examined witli a Umis. (hiring tlie sectioning, and any particular vessel or vessels included, in a section. Also, sections may be made of different shapes.

HLOOD-VKSSKLS OF TIIK XKAH Ffl.T.-TKlOI FKTIS

In order to determine as near as j>ossible the arrangement of the blood-vessels of the s|)inal cord in the adult comlition, a iHnnl)er of f(>tal pigs, neai' full-term, were injected and their spinal cords dissected out for study. Alt liough these showed some variation in the blood-vessels, as is to be expected, a general

374 E. K. HOSKINS

plan was to be olisorvod. The following descrii)ti()n i.s of the tj'pical condition found in the blood-vessels in and around the spinal cord of pigs of about 240 nun. in length:

The terminology used by Kadyi ('89) for the blood-vessels of the adult human cord will he rt^ferred to frequently.

On the surface of the cord at this stage are four main longitudinal arterial systems which are located, one, median on the ventral surface; one, on each dorso-lateral surface; and one median on the dorsal surface.

The vertebro-meduUary branches of the dorsal segmental arteries approach the cord laterally and each divides into a dorsal and a ventral branch termed the posterior and ventral radical arteries respectively (figs. 1 and 2). The latter reach the cord along the cranial surface of the spinal nerves and ganglia, and, on the cord, run cranially. The}^ may be equally distributed to the two sides of the cord and to the different regions of it, or some regions may ha\'e more than others. They average eighteen in number. The \Tntral and dorsal radical arteries have lost their connection wdth the vertel)r()-medullary artery in places and extend between the artery on the ventral surface of the cord and one of those on the dorso-lateral surfaces.

Soon after reaching the cord each ventral radical artery branches, giving off one ramus which courses cranially, and another which extends caudally. These divisions anastomose with those of neighboring ventral radicals, on the same or opposite side

Fig. 1' Ventral svirfarc of the iimldlr thoracic- regiou of the spinal eonl of a fetal pig, 240 mm. in length. .4..S..4., anterior spinal artery; A.R.W, ventral radical artery; T.A.P., accessory anterior spinal artery (remains of primitive arterial tract); V.R.V., ventral radical vein; V^..S..4., anterior s])inal vein; C.P., capillary plexus. X 0.

Fig. 2 Dorsal surface of I he same part of t he eoid shown in figure I. A .M .D., median dorsal artery; A.P.L.. dorso-iatcral artery; A.R.I)., dorsal radical artery; V.^f.I)., median dorsal vein; V .I'.L.. dorso-lateral vein and plexus; V.R.D., dorsal radical vein; \'.fj.. dorso-laleral venous plexus. X 10.

' The figures in this pajx')-, exc('i)t nunilKMs '.] and I, were drawn witji a camera lucida. The size of the eml)ryf)s is the greatest length, as iiieasured in 7.") per cent alcohol.

.J^^ft"

-*1^,

TA P-1

.-■)■■

I

tC.P

>, '

375

37(3 E. R. HOSKINS

of the cord, and form in this way the anterior spinal artery, which Ues in or near the median ventral line. Occasionally a radical artery, instead of dividing, goes across the cord and joins the cranial or caudal ramus of the one on the opposite side. The anterior spinal artery has a winding course, bending laterally to meet the vessels which form it, and making many smaller irregular bends to one side or the other. In some places it may lie to one side of the mid-line for several segments and where this occurs there are found numerous longitudinal rami of the anterior spinal artery, or the cranial antl caudal tlivisions of the ventral radicals. These may be called accessory anterior spinal arteries, and are sometimes present even where the anterior spinal artery lies in the mid-line. Here they are located between this vessel and cord, at the lip of the ventral median fissure. They are the remnants of the "tractus arteriosus primitivus" of Sterzi.

The dorsal radicular rami of the vertebro-medullary arteries are much more numerous than the \'entral ones. They course dorsally along the cord and in a slightly cranial direction, to a plane just ventral to the emergence of the dorsal roots of the spinal nerves, where they divide into two rami, one extending cranially and one caudally. Each of these rami anastomoses with the one of the adjacent segment, and thus there is formed on either side an irregular longitudinal vessel, the dorso-lateral artery (fig. 2; tractus arteriosus postero-lateralis of Kadyi). From this artery recurrent rami supply the dorsal nerve roots and si:)inal ganglia, and the lateral surface of the cord. Other rami, two or three in each segment, and much larger than the above, run dorsally and by longitudinal anastomoses with each other, and with similar rami from the opposite side, form an artery in the mid-dorsal line which may be termed the median dorsal artery.

Wry small rami from the dorso-lateral arteries run ventrally along the cord and unite with oth(M"s from the anterior spinal artery, forming a plexus on the ventral and lateral sides. These ventral rami of the dorso-laterals anastomose freel_y in a longitudinal direction and form one or more small longitudinal arteries between the ventral and dorsal nerve roots in some parts of the cord. These are the tracti arteriosi laterales, and ventro-later

VASCULARIZATIOX OF THE SPINAL CORD 377

ales, of Kadyi. Still other small rami from the dorso-lateral and median dorsal arteries form a capillary plexus on the dorsal and dorso-lateral surfaces of the cord. In a few places along the cord the dorso-lateral arteries are double, one divisif)n lying dorsal to the dorsal nerve roots, and corresponding perhaps to the '"tractua arteriosus posterior" of Kadyi.

The median dorsal artery is a very irregular longitudinal vessel formed by the dorsal rami of the dorso-lateral arteries, as described above. In places it is double or ma\' show a longitudinal capillary arrangement. Many of its lateral rami anastomose longitudinally forming small arteries parallel with the median dorsal artery (fig. 2). This is also true of the dorsal rami of the dorso-laterals. By the anastomoses of the rami of the various arteries just described, the entire cord is surrounded by an arterial vascular system, and from all parts of this network smaller arteries penetrate its substance.

The veins of the spinal cord are in three princijial longitudinal systems, and other smaller ones. Of the three, two are dorsal and one ventral. All three show evidence of their capillary origin. The anterior spinal vein is the smallest of the three (tig. 1). It lies between the cord and the arteries, in the median ventral line. It is larger than the accessory anterior spinal arteries, but never attains the size of the anterior spinal artery i)r()i)er. It is very irregular and in some regions is entirely replaced by a narrow network of capillaries.

On either side of the median ventral sulcus, the cord is covered with large venules, some of which lie between the cortl and the arteries, and some of which are external to the latter. They are often two or three times as large as the arterioles to which they correspond. They anastomose freely with the anteri«)r spinal vein and empty laterally into the ventral radical veins which are in close relation with. the ventral nerve roots and ventral radical arteries, but which are nuicli nu^v numerous tiian the latter, one being present on nearly every nerve root. They ilrain blood also from the lateral sm-face of the cord. Their ventral and dorsal rami often form short, small, longitudinal veins by anastomoses, some of which in otluM- animals have been named, antero-lateral.

378 E. R. HOSKINS

etc. The 1)1()()(1 from tho anterior spinal veins and venous capillaries of the gc'neral ventral surface form, in places, transverse channels which are perhaps large enough to be called veins.

On either side of the dorsal surface of the cord there extends longitudinall}' a large irregular vein, the dorso-lateral, about half way between the artery of the same name, and the median dorsal artery. Some parts of these vessels and their rami, like the ventral venous capillaries, lie external to the arteries and some internal to them. They are the largest vessels on the cord with the exception of the anterior spinal artery (compare figs. 1 and 2). Dorsally these veins are united through large capillaries, and blood leaving the cord in the median line may flow either to the right or left. Half way between two consecutive nerve roots the dorsolateral veins usually break up into many divisions so that each may be seen to drain blood from adjacent halves of two segments. Laterally' they empty through one or more divisions into the large dorsal radical veins, one of which lies upon each dorsal nerve root (fig. 2).

A fourth longitudinal venous system, smaller than the three described, lies in the median dorsal sulcus. It resembles the dorso-lateral veins except that it is more irregular, and in places it may be entireh^ lacking. Its lateral rami empty in the dorsal venous capillary plexus or directly through larger vessels into the dorso-lateral veins. It may be termed median dorsal venous system.

Some of the venous capillaries of the lateral surface drain into the dorso radical veins, some into the dorso-lateral veins, and some into ventre radical veins, and all these vessels together with the anastomoses of the veins on the ventral and dorsal surfaces already mentioned above, completely surround the cord with a venous system, corresponding to the system described for the arteries.

Of the arteries entering the cord, the largest are those in the ventral fissure, the ventral central arteries, which form two nearly parallel rows, but which are not paired. They arise from the anterior spinal arteries, or the accessory anterior spinal arteries. They show evidence of the capillary origin in longitudinal anas

VASCULARIZATION OF THE SPINAL CORD 379

tomoses found between vessels of the same side. These anastomoses are numerous in the fissure, particularly near the vessels from which the ventral central arteries arise.

The ventral central arteries vary considerably in size, some being as large as the vessels they arise from and others much smaller (fig. 3) . The course of the smaller vessels is usually more irregular than that of the larger. They pierce the substance of the cord at different levels, some entering near their origin and others extending some distance into the fissure. Their general course is dorso-lateral, but those entering near the mouth of the fissure may bend very sharply to the side and enter the ventral horn of the gray substance. The others course more dorsally nearly to the level of the central canal where they make a decided lateral bend, and divide into two or more rami, although sometimes they give off rami more ventrally than this (figs. 3 and 4i. The principal divisions of these arteries extend in a longitudinal plane, and anastomose with similar rami of adjacent vessels. They also give off smaller arteries and capillaries which ramify through the gray matter in all directions, helping to form a dense plexus. The longitudinal arteries tend to form loops after they have coursed in one direction for a short distance, as thej' do in young embryos (fig. 5). One artery may form several such loops, producing as many longitudinal vessels, each succeeding vessel lying dorsal or lateral to the last, and of a lesser cahber. These smaller longitudinal vessels anastomose with each other ventro-doi*sally and laterally by rami which usually leave them at right angles, and also anastomose with rami from vessels other than the ventral central arteries, as will be described later.

Besides the rami of the central arteries just described, other rami extend farther laterally into the gray substance before l)ranching. Some of these, instead of ft)rming longitudinal vessels, form small irregular ones which ramify through the gray matter in all directions, anastomosing with similar vessels from other arteries in this region and forming a dense capillary plexus in the ventral and dorsal horns.

Other arteries, smaller than the ventral central arteries, enter the c(ird from the dorsal median sulcus and course ventrallv and

380 E. R. HOSKINS

laterally to tlio dorsal horns of tho gray substance. Here they form still smaller vessels resembling to some extent those formed by tlie \'entral central arteries, but most of their rami are short and do not extend longitudinally. These may be called the dorsal central arteries, but they are more similar to the peripheral arteries from other surfaces of the cord, than to the ventral centrals, and perhaps should be called dorsal peripheral arteries. They give ofT many small lateral rami in the white substance and in the outer part of the gray substance.

In addition to these vessels, other small arteries enter the cord from all sides, from the arteries and arterioles which surround it. These are the peripheral arteries referred to above. The}^ are very numerous and in a single thick cross section as man}^ as fifty or sixt}' of them ma}^ be counted. They give off short rami in the white layer of the cord and extend into the gray layer. These rami branch and anastomose and form a loose capillary network. The vessels entering the gray substance enter into the longitudinal plexus already described and give oflf lateral rami which branch freely and anastomose.

The longitudinal vessels which arise from the ventral central arteries are quite large, but the other vessels formed from these trunks, and those formed from the dorsal central and peripheral arteries, are much smaller. A very thick section presents a l)icture of an inner core of longitudinal vessels with other vessels extending into it at right angles from all points on the periphery of the cord (figs. 3 and 4).

Via. 3 Saf!;ittal section from tlic lower thoracic region of the .si)inal coni of a 240 mm. fetal pig. A.S.A., anterior spinal artery; .l.f. /I ., ventral central artery; ,1./'., peripheral artery; A.C.P., dorsal central artery; r..S..4., anterior spinal vein; V.C.A., ventral central vein; \'.('.l'., dorsal central vein; l'./'.. jx-ripheral vein. X 3.5.

Fig. 4 Transverse section through the lower thoracic region of the spinal cord of a 240 mm. fetal pig. A.S.A., anterior s|)inal artery; A. P., peripheral artery; A., artery; A.C.A., ventral central artery; S.A.S.A., accessory anterior spinal artery; A.I'.L., dorso-Iateral artery; A.M.D., median dorsal artery; .t.N.r., anterior spinal vein; V'., vein; V.P., peripheral vein; V.P.L., dorso-latcral vein; 1'.. !/./>., median dorsal vein. X 35.

A VMD AMD AP

382 E. K. HOSKINS

DKNKLor.MKNT OF TH1-: HL(>()I)-\KSSELS

The early development of the anterior spinal artery has been described by Evans ('09) and Sterzi ('04).

Some pig embryos of 12 mm. show a fairly well developed anterior spinal artery, while in others of 14 or 15 mm. it is just beginning to form. Although, after this vessel is once formed, it does not undergo marked changes, there is some modification. For example, the ventral radical arteries meet it at right angles or nearly so, until the embryo is 40 or 45 mm. in length. Thereafter, the growth of the cord and the fixed position of the radicals seem to cause the artery to be pulled laterally by the radicals, and a gradually decreasing angle is formed at the points where the radicals meet it (fig. 1).

As the embryo grows, the number of radical arteries continues to decrease even after the anterior spinal artery is well formed. This seems to be true until the embryo reaches the length of about 100 mm.

Some of the arterial capillaries on the ventral surface of the spinal cord are continuous with the anterior spinal artery directly, or indirectly through remains of the tractus arteriosus primitivus, and others are continuous with the capillaries of the lateral surfaces of the cord.

A dorso-lateral artery is formed in the capillary plexus on each of the lateral surfaces of the cord, just ventral to the point of emergence of the dorsal nerve roots. The dorsal radical arteries branch in this region and give oiT dorsal and lateral rami, which are continuous with the lateral capillaries just mentioned. A very irregular longitudinal vessel develops where certain of these

Fig. .5 Transverse section through the mid thoracic region of the spinal cord of an 11 mm. |)ig embryo. T.A.P., primitive arterial tract; R.D.T.A.P., R.L. T.A.I'., R.M.. dorsal, lateral, and medial rami of the primitive arterial tract; A.V..\I., vertehro-medullary artery; A.R.V., A.R.D., ventral and dorsal radical arteries; C.R., Cr.R., D.R., V.fi., caudal, cranial, dorsal and ventral rami of the dorsal radical artery; I). P., D.L.P., dorsal and dorso-lateral capillary plexuses; D.L.C.G., V.L.C.G., dorso-lateral and ventro-lateral groups of peripheral capillaries; V.L.V.P., ventro-lateral venous plexus; V.R.V., V.R.D., ventral and dorsal radical veins; S.P.G., spinal ganglion; V.N.R., D.N.R., ventral and dorsal nerve roots; S.N ., spinal nerve. X 200

VASCULARIZATION OF THE SPINAL CORD

383

3S4 E. R. HOSKINS

capillarios iiuToaso in sizc\ perhaps on account of the increased pressure from the dorsal radical arteries. This longitudinal vessel is indicated in embryos of 12 mm. and is quite stronglj' developed in embryos of 15 to IS nnn. In these stages it seems to dip ventrally to meet the approacliing radicals, as pointed out by Sterzi for the sheep ('04). -Vs the embryo grows, this dorso-lateral artery becomes more and more regular. It is still somewhat irregular in embryos of (30 mm. but quite regular in those of 75 mm. The dorso-lateral artery never attains the size of the anterior spinal nor is it ever so regular in its course. In places it may develop as two or more vessels, but these are always smaller than the single artery. The dorso-lateral arteries are each continuous with the capillaries of half the cord in the early stages, but as the cord increases in size they supply directh^ only the dorso-lateral surface.

The capillary network on the lateral surface of the cord is at first continuous with tliat extending through the mesenchyma of this region as far, laterally and dorsally, as the myotomes and body wall respectively. In later stages when the membranes of the cord begin to develop, the connections between the vessels of the cord and those in the mesenchyma around it are lost.

The median dorsal artery is the last of all the vessels on the cord to develop. In pigs of 30 nun. it is still very irregular and indefinite, and is entirely lacking in places, although the vessels which go to form it, the dorsal rami of the dorso-lateral arteries, may be seen in embryos of 20 mm. In pigs of 45 mm. it is quite definite, lying in or near the mid line of the dorsal surface, as described above for the 240 mm. embrj'o It never becomes very regular, and in pigs of 100 nnn. it resembles the condition seen in the pig oi 240 mm. It is continuous with the arterial caj)illaries of the dorsal surface of the cord and with the dorso-lateral arteries.

In addition to these main arterial trunks there develop on various parts of the cord, especially on the lateral surfaces, short longitudinal arteries. These are never large or regular. The}' have been desci-ibcd in connection with adult human coi-d under the terms "tractus arteriosus; ventro-lateralis, posterioris, and

VASCULARIZATION OF THE SPINAL CORD 385

lateralis" (Kadyij. Of these, the "tractus arteriosus posterior" is the most prominent and corresponds to the description in this paper of parts of the dorso-lateral artery, where it sometimes has two divisions, one of which runs dorsal to the dorsal nerve roots and the other ventral to them. The dorsal divisions are evidently the same as this ' tractus. '

The veins on the cord develop in much the same way as do the arteries. The ventro-lateral surface of the cord in very young embryos is covered with capillaries, and these are continuous laterally with the capillaries in the mesenchyma round the neural tube. Medially they become continuous with the lateral rami of the primitive arterial tract. When this tract becomes separated from the cord by the ingrowth of mesench>niia, these capillaries send medial outgrowths between the tract and the cord, as seen in embryos of 12 to 15 mm. Dorsall}' the}' grow along the cord and spread over the dorso-lateral surface (pigs of 6.2 mm.) and later over the dorsal surface (pigs of 7.5 mm.). Laterally they spread over the ganglia.

From the ventral surface, the blood draining away through the capillaries soon establishes segmental vessels, the ventral radical veins, which course laterally along the nerve roots. Each radical vein on one side drains adjacent halves of two segments. These receive blood from the capillaries of the ventral, lateral, and ventro-lateral surfaces. Lying in the ventral median fissure in young embryos, small longitudinal veins may be seen in different regions of the cord, and in embryos of 25 to 30 mm. a fairly detinite longitudinal vessel may be found here. This vessel in still older embryos becomes a more definite trunk and may be called the anterior spinal vein. It never attains the size of the anterior spinal artery. Laterally it drains into the ventral radical veins.

Some of the ventral and lateral capillaries of the younger embryos, early become dilYcrentiated into veins. This is especially true of the dorsal vessels. From these, some of the bUxxl drains laterally out through vessels in the mesenchyma to the myotomes. .\ pig of (').2 mm. shows three planes in whicii this occurs, one on a le\el with tlu^ dorsal surface, one just al)ove the level of the ven

3S6 E. R. HOSKINS

tral surface, and one about half way between the other two. At the myotomes the blood drains Aent rally into the intersegmental veins. Some of the capillaries of the lowest of these three planes, which tlrain the blood from the lateral surface of the cord and from the ganglia, soon become large and are called the vertebromeduUary veins, one pair of which is formed for each segment. In older embryos they course along the spinal nerves with the vertebro-meduUary arteries. They recei\e the blood from the ventral and dorsal radical veins. The former have been described. The latter develop along the sides of the gangUa in the capillaries already mentioned. At firsi they carry only a part of the blood from the dorsal surface of the cord, but later (pigs of 25 mm.) they carry practically all of it. They are more numerous than the corresponding ventral radicals, and are found in every segment.

The venous capillaries of the dorsal-lateral surface on either side draining toward the nerve roots early establish longitudinal veins. These are onlj' about half as long as a segment of the cord. Figure 5 of an 11 mm. pig, shows an indifferent plexus on this surface, but in 15 to 17 mm. embryos, fairly definite vessels may be seen. These become more and more regular as the animal develops, and as embryos of 50 to 60 mm. show, they form a venous system on either side of the cord just dorsal to the dorsal nerve roots, much like that described for the 240 nun. stage. These systems constitute the dorso-lateral veins (fig. 2).

The first blood vessels entering the cord grow in as capillaries from the ventral surface. Sterzi ('04) reports vessels in the cord of a sheep of 5.5 nmi., but they were not apparent in the cord of pig embryos of less than 7.5 nmi. These vessels are the dorsal rami of the primitive arterial tracts, of the lateral rami of these tracts, and of the other capillaries near the median line. They are the first indications of the central arteries and veins. They form two nearly parallel rows, one on either side of the epend>nnal layer, f)r some of them may lie in this layer. They grow dorsally about half way to the dorsal surface of the cord. They exhil)it numerous longitudinal anastomoses and form a plexus along the ateral side of the ependymal layer in each half of the cord. These are true capillaries at first, but soon differentiate into arteries and veins.

VASCULARIZATION OF THE SPINAL CORD 387

Those coming directly from the primitive arterial tracts all become arteries, while those coming from the vessels lateral to the tract may become either veins or arteries.

In embryos of 9.5 mm. another group of capillaries may be seen to have entered the cord. These come from tjie lateral surface, extending medially nearly to the central canal. Later they anastomose ventro-dorsally and longitudinally, among themselves and with the vascular sprouts from the ventral surface.

The vessels in the cord of a pig of 11 mm. present the following characteristics, as shown in figure 5. Rami from the primitive arterial tract may anastomose with those from the ventral capillaries. Neighboring vessels of the same kind anastomose freely and give off lateral rami into the anlagen of the ventral horns of gray substance. These rami branch and anastomose with each other and form loops which anastomose with the central vessels from which they arise, or with neighboring vessels. In a plane just above the anlagen of the ventral horns each of the central vessels ends blindly, or divides into a caudal and a cranial ramus, which anastomose with adjacent similar rami and form irregular longitudinal vessels. By other anastomoses among the central vessels, a longitudinal plexus is formed, which covers very coinpletely the lower half of the lateral side of the ependymal layer.

A comparison of figures 3 and 5 shows how closely the form and arrangement of these capillaries corresponds to that of the future central arteries and veins. Besides these main capillaries two smaller lateral groups are present at this stage. These may be called the ventro- and dorso-lateral groups, and later fonn peripheral arteries and veins. Both groups enter the cord from the capillaries on the lateral surface between the dorsal and ventral nerve roots. The ventro-lateral group enters at the level of the dorsal extremities of the central vessels, and courses medially and anastomoses with them. Occasionally the ventro-lateral group gives off rami which extend into the anlagen of the ventral horns. The capillaries of the dorso-lateral group are confined to the dorsal two-fifths of the cord, and although they anastomose with each other at this stage, they do not anastomose with the central or ventro-lateral capillaries. They course medially and

THE ANATOMICAL RECOBO, VOL. S, NO. 7

388 E. R. HOSKINS

dorsally along the ependjana, ending blindly or forming loops, but do not reach the dorsal surface.

As development proceeds, the lateral groups of capillaries shown in figure 5 spread dorsally and ventrally and capillaries enter the cord from the periphery. With the exception of the above-mentioned dorso-lateral group of capillaries, all the vessels entering the sides of the cord grow toward a common center, namely, an area on the lateral border of the ependyma about half way between the dorsal and ventral surfaces. The dorso-lateral group of capillaries which are shown in the same figure send rami toward this center after the embryo attains the length of 14 mm.

The vessels from the dorsal surface grow ventrally along the ependyma and unite with the dorsal rami of the primitive arterial tract. This union continues the plexus on the lower part of the epend>Tna dorsally so that the ependyma except below the floorplate and above the roof-plate, is entirely surrounded by a capillary plexus. A thick transverse section of the cord of an embryo of 25 mm. shows this plexus with numerous vessels extending from it laterally at right angles. These lateral vessels are joined together by dorso-ventral rami. This picture is characteristic of the cord until the embryo reaches the length of 30 or 35 mm. when it is changed by other peripheral vessels meeting the ependymal plexus obliquely and by the branching of the vessels in the anlage of the gray substance.

By this time the central arteries from both the ventral surface (ventral central arteries) and from the dorsal surface (dorsal central or dorsal peripheral arteries) have become quite large, although the latter do not nearly equal the size of the former. The ventral central arteries have formed more longitudinal loops similar to those shown in figure 5. They are separated more and more from each other, owing to the growth of the cord, and as this separation continues the longitudinal vessels grow in length.

In embryos of 35 to 40 mm. in length the peripheral arteries from all sides together with the lateral rami of the central arteries have formed a dense plexus in the gray substance, although the white substance contains only the peripheral arteries running through it, and the short branching rami given off at right angles

VASCULARIZATION OF THE SPINAL CORD 389

from them. By the time the embryo reaches a length of 50 mm. the capillaries in the white layer have much the same appearance as those of the full term fetus, except that in the latter they branch and anastomose more freely and the growth of the cord tends to separate both the peripheral vessels and the central vessels. Embryos of 75 to 100 mm. in length show the arteries in the cord quite as completely developed as in the 240 mm. embryo.

The posterior rami of the primitive arterial tract in the ventral part of the cord of embryos of 12 to 15 mm. are more numerous than the central arteries in the 240 mm. embryo which are formed from them.

The veins within the cord develop in the same planes as the arteries, and from the same plexus of capillaries that form the latter. They may be called the central and peripheral veins corresponding to the similarly named arteries. They are shown in figures 3 and 4 in a fully developed condition.

SUIVIMARY

The dorsal rami of the primitive arterial tract, and other rami from the capillaries in its immediate vicinity enter the cord, forming an undifferentiated capillary plexus (fig. 5) and this plexus later becomes differentiated into arteries and veins. It was not found, as stated by Sterzi for the sheep, that each dorsal ramus of the primitive arterial tract grows into the cord, and forms a loop, giving rise to a vein which grows back along the artery to the ventral surface.

The dorsal rami of the primitive arterial tract are more numerous than the ventral central arteries which develop from them.

Sterzi reports solid blood-vessels in the cord of sheep of 5.5 mm. and hollow ones in those of 6.6 mm. In pig embryos the bloodvessels within the cord seemed to appear first as hollow vessels. These are seen first in embryos of 7.5 nmi. in length.

The "tracti arteriosi laterales" of Sterzi, are the dorso-lateral arteries of this and postero-lateral of other papers, and are the posterior spinal arteries of human descriptive anatomy. Evans shows these two tracts first united by medial anastomoses in a

390 E. R. HOSKINS

pig of 8.5 nun. in length, but many such anastomoses are to be found in embryos as small as 7.5 mm. in the cervical and thoracic regions, and one specimen of 6.2 mm. showed them in the cervical region.

The embryos described in this paper show the mid- ventral and mid-dorsal surfaces of the cord to be covered with blood-vessels at a somewhat earlier stage than has been described.

As reported by Sterzi ('04) and Evans ('09), blood-vessels first appear on the ventro-lateral surface of the cord, then on the ventral, then on the dorso-lateral, and finally on the dorsal surface.

The blood-vessels on the cord are continuous with those in the mesenchyma surrounding it until the membranes of the cord are formed.

It is generally stated in textbooks of human anatomy that the spinal artery arises from the vertebral arteries, and is reinforced by segmental spinal arteries. It il rather to be considered that this artery arises from the segmental spinal arteries, and anastomoses with, or is reinforced by, the vertebrals.

The term median dorsal is suggested for the artery present in places in the median dorsal line of the spinal cord.

My thanks are due to Dr. Richard E. Scammon for his constant interest in the progress of this work, and for his many helpful criticisms.

VASCULARIZATION OF THE SPIXAL CORD 391

BIBLIOGRAPHY

Adamkiewicz, a. 1881 Die Blutgefiisse des Menschlichen Riickenmarkes. I. Teil: Die Gefasse der Ruckenmarksubstanz. Sitzungsber. k. Akad. Wiss., Wien, Math.-Xaturwiss. Kl., Bd. 84, iii. Abt.

1882. II. Teil: Die Gefasse der Riickernmarksoberflache. Sitzungsber. d. k. Akad. d. Wiss., Wien, Math.-Xaturwiss. Kl., Bd. 84, lu. Abt.

DoRELLE, P. 1911 Rapporti tra encefalomeria e vascalarizzazione. Del cervello embrionale. Ricerche Lab. Anat. Xorm. R. L'niv. Roma, voL 15.

EvAXS, H. M. 1909 On the development of the aortae, cardinal and vunbilical veins, and other blood vessels of vertebrate embryos, from capillaries. Anat. Rec, vol. 3, p. 498.

1909 On the earliest blood vessels in the anterior limb buds of birds, and their relation to the primary subclavian arterj'. Am. Jour. Anat., vol. 9.

1912 Development of the vascular system. In 'Human embryology,' Keibel and Mall, vol. 2.

His, W. 1887 Zur Geschichte des Menschlichen Riickenmarkes und der Xervenwurzlen. Abhandl. der Konigl. Sachs. Gesellschaft, der Wissenschaften 22. Math.-Phys., Classe 13, Leipzig.

HocHE, A. 1899 Vergleichenden-anatomiches iiber die Blutversorgungen der Ruckenmarksubstanz. Zeitschr. Morph. u. Anthrop., Bd. 1.

HoF.MAX, M. 1900 Zur vergleichenden Anatomie der Gehirn und Riickenmarksarterien der Vertebraten. Zeitschr. Morph. u. Anthrop., Bd. 2.

Kadyi, H. 1889 Ueber die Blutgefasse des menschl. Ruckenmarks. Wien. (Also Denkschr. Math. Xatunv. Kl. Akad. Wissensch. Krakau).

Ross, J. 1880 Distribution of the arteries of the spinal cord. Brain, vol. 9.

Smith, H. W. 1909 On the development of the superficial veins of the body wall in the pig. Amer. Jour. Anat., vol. 9.

Sterzi, G. 1904 Die Blutgefasse des Ruckenmarks. Anat. Hefte, Bd. 24.

A COURSE OF CORRELATIONAL ANATOMY

EDWARD F. MALONE

From the Department of Anatomy, University of Cincinnati

During the first year and a half of study the medical student acquires a knowledge of certain aspects of the structure and function of the human body. Since these different aspects are studied in separate courses the tendency is for the student to acquire certain disjointed groups of facts which neither his ability nor the time at his disposal permit him unassisted to bring together. Such a mass of fragmentary knowledge falls far short of what the student is supposed to have acquired, namely, a reasonably good understanding of the structure and activities of the entire organism. It is true that in every good course the instructor brings the subject matter of his speciahty into relation with that of other courses; this correlation in the separate courses is indispensable and serves as a foundation for further efforts in this direction, efforts made by the student alone, or preferably under suitable supervision. But in attempting in each course to correlate the subject matter with that of other courses the results obtained are inadequate, not only on account of the lack of sufficient time but especially because the knowledge of the student is as yet too limited. It therefore appears advisable, after the various courses involved have been completed, to renew in a special course the effort to help the student bring together certain important facts already learned piecemeal. This article deals with such a course introduced this year by the Department of Anatomy of the I'niversity of Cincinnati.

The course in correlational anatomy is the logical result of the method of instruction in the Department of Anatomj'. The head of the department, Professor Knower, has in all the work of the department constantly insisted upon the correlation of

393

394 EDWARD F. MALONE

structure and function. And accordingly those portions of the body which are of the greatest functional importance have in the courses of the department received the gi'eatest attention. A further advance consists in the increasing correlation between the different courses of the department (gross anatomy, histolog>', neurology and regional anatomy). The work in gross anatomy and in histology is so related that the student studies the gross and microscopic anatomy of each organ simultaneously, as far as this is practicable; this is only one instance of the correlation of work within the department. In the second year the association of gross anatomj', histology, physiology, neurology and regional anatomy is much closer. This intimate relation between the separate courses within the department is maintained by the close association of the various members of the staff so that each member is familiar with the nature and progress of each course; this knowledge is attained not only by means of frequent conferences but also through actual experience in assisting from time to time in each course. On the other hand, such a correlation of courses within each department makes additional demands upon the staff, demands which are difficult to meet unless the department be supported in a more liberal manner than is customary. It is manifestly unreasonable to blame the student for regarding different courses as uru-elated when the instructors themselves behave as if this were true, and it is also unreasonable to expect instructors to establish such a correlation if they be already overworked. It is upon this intimate association of the different courses within the department that the course in correlational anatomy is founded. AMiile the author has designed this course and has conducted it alone, he does not claim the entire credit of originating it, since it is the result of the whole attitude which Professor Knower has impressed upon the department.

In addition to correlating its own courses and introducing a considerable amount of general biolog>', embrj^ology and physiology, the Department of Anatomy has repeatedly requested other departments to send students back for supplementary study whenever these departments demand special anatomical knowl

A COURSE OF CORRELATIONAL ANATOMY 395

edge which the student cannot and should not obtain during his regular courses in anatomy. Such supplementary work has proved of great advantage to the students, since it is undertaken by trained men who realize the need of the knowledge which they return to- acquire, and they gladly accept the opportunity. The advantages which an anatomical laboratory- possesses as against didactic teaching are evident. This arrangement is impossible if the student's time be completely occupied by required work; in addition it makes demands upon the time of the anatomical staff, and the question arises as to whether the institution is willing to pay for such advantages to the students or whether it will take the course of least resistance and of least expense.

The course in correlational anatomy is given at the beginning of the second semester of the second year. Before it begins the student has finished dissecting the body and has completed, beside other courses, those in histology', physiolog\' and neurolog\'; in addition, he has studied the various aspects of anatomy from a physiological standpoint. During this year and a half the student has amassed a large number of facts and has made some progress in bringing isolated facts together; moreover, he has attained to a considerable degree the abihty to recognize essentials and to work problems out for himseh. The course in correlational anatomy lasts eight weeks, and during the remainder of the second semester the student is at liberty to elect such work in the department as he may desire; he may take the course in regional anatomy, or he may spend the time reviewing the essentials of the body, working out for himself (with the assistance of the staff) certain important mechanisms not given in the course in correlational anatomy. This course is accordingly preceded by the study of the structure and function of the entire body, and is followed by a period during which the student has the opportunity of bringing together on his own initiative further disconnected groups of facts; in this manner the student is encouraged to fonn the habit of study outUned in the course just completed so that he may thus acquire a real knowledge of the human body. This result is aided by the fact that at the end of the second vear he

396 EDWARD F. MALONE

must pass an examination which includes all the subjects studied in the department and in which a fair but real knowledge of the essentials of the body is demanded.

At this point the author would like to enter a protest against the unfortunate tendency in some institutions to complete the work in anatomy during the first year. The student can undoubtedly finish the courses in histology and neurology and dissect the entire body in one year, but even if the time should be sufficient to permit the student to finish his task without undue haste the result would still be unsatisfactory. For a real knowledge of anatomy cannot be acquired all at once, but only when the study is prolonged to such an extent that the student has the repeated opportimity of thinking of the problems which the dissection of the body merely makes possible to study. ^Moreover, the student's knowledge of physiology and his capacity for independent constructive thinking is too limited to permit him to obtain an adequate knowledge of the body during the first year. Finally, this excessive concentration and hurry encourages the student to regard each of the anatomical courses (and each part of each course) as a separate task to be gotten out of the way in a definite length of time, and not as aspects of one great problem to be correlated with one another and with those aspects learned in other departments.

The course in correlational anatomy consists in the study of certain mechanisms of the body. New matter is introduced only when necessary, while on the other hand, unessential details are eliminated. The course therefore attempts to help the student rescue from the mass of details the really vital facts concerned in each mechanism, and by correlation of these facts to fix them firmly in his memory. Especial emphasis is placed upon the relation of the nervous system to the rest of the organism, and the various reflexes involved in the activities of each mechanism are studied thoroughly, the path of the impulse being followed throughout its entire extent. The course differs from one in physiology in that the anatomical structures upon which depend the activities of any mechanism become to the student realities; as far as possible the actual anatomical structures are

A COURSE OF CORRELATIONAL ANATOMY 397

studied in the gross and in sections, and in the nervous system the actual location of nervous centers and the course of fiber tracts are reviewed not only in diagrams but also in the specimens themselves.

For the most part the student is expected to work out, with the aid of specimens and books, the various problems for himself. Since all anatomical and physiological facts involved have been previously studied it is possible to assign at each exercise a large field to be covered, and to expect the student, with a certain amount of guidance, to select the most vital points and to ignore nonessentials; the value of this training is evident. 'S^Tiile lectures are necessary they are mostly informal, assuming the character of conferences, while at the beginning of each exercise the main results of the work of the preceding day are briefly summarized. Finally, the student is expected to hand in at the end of the course a complete account of the mechanisms studied, and to describe certain activities which have not been studied but with whose anatomical basis he is supposed to befamihar.

In selecting topics for study in a course in correlational anatomy the following points should be kept in mind:

1. The topics should be of importance.

2. They should necessitate the study of structures which form part of many other functional groups, and which thus involve a knowledge of large portions of the body.

3. They should involve functions which have a demonstrable anatomical basis.

The respiratory system meets these requirements in a most satisfactory manner. It is of great importance; it demands the study of the entire thorax, a part of the head and neck, the spinal cord and spinal nerves, the vagus and trigeminal nerves, the s>inpathetic system, and the main sensory and motor tracts and centers of the brain; and finally, the correlation between stucture and function can be shown in a most satisfactory manner. The almientary system also is satisfactory in most respects. Although the correlation of structure and function is not easily shown in the portion below the diaphragm, in the portion above the diaphragm this can bo shown vorv successfullv.

398 EDWARD F. MALONE

The study of the anatomical structures of the ahmentary tract involves many hnportant relations in the head, neck, thorax and abdomen. The relation of the nervous system to swallowing and to mastication (taken in a very broad sense and including prehension and other acts preparatory to mastication proper) involves many reflexes in which practically the whole nervous system is utilized; of course the regulation of secretion and of blood supply should be included. .Ajnong other mechanisms which suggest themselves as suitable for study may be mentioned the maintenance of the erect position (including the part played by the nerv^ous system in receiving, correlating and sending out impulses), the heart beat, the development and mechanism of speech together with the different forms of aphasia.

The course in correlational anatomy this year was limited to sixteen periods of three hours each; next year it will be extended. An outline of the course follows:

I. Respiration

1 February 19 The thoracic wall and its movements

2 February 20 Relations of the thoracic contents. Diaphragm

3 February 26 Gross anatomy of nose, pharynx, larynx and

trachea

4 February 27 Histology of respiratory system

5 March 5 Mechanics of respiration

6 March 6 Nerves and nervous centers

7 March 12 Nervous reflexes

8 March 13 Summary

II. Mechanisms of the alimentary system

A. Mastication

9 March 19 Gross and microscopic anatomy of the mouth

10 March 20 Nerves and nervous centers

11 March 26 Mechanism of mastication

B. Deglutition

12 March 27 Gross and microscopic anatomy of tongue,

pharynx and esophagus

13 April 2 Mechanism of deglutition

C. Movements of stomach and intestines

14 April 3 Gross and microscopic anatomy of stomach and

intestines

15 April 16 Movements and nervous mechanism of stomach

and intestines

16 April 17 Lecture

(a) Sympathetic system

(b) Innervation of viscera and of overlying muscles and skin

(c) Theory of emotions

A COURSE OF CORRELATIONAL ANATOMY 399

In order tc make such a course a success the instructor should carefully avoid each of two extremes. In the first place, the course may degenerate into a feeble attempt at a review in physiology' in which the student, neglecting to study in actual preparations the anatomical structures upon which the various functions depend, spends his time over a book or in theorizing. In the second place, the student may become lost in a maze of anatomical details, losing sight of really vital anatomical facts and failing to bring these into relation with the activities which depend upon them. The instructor should possess above all a thorough knowledge of the anatomy and physiology of the nervous system; in addition he should be familiar with the gross and microscopic anatomy of the entire body and with general physiology', while a knowledge of pathology', clinical neurology, psychology and psychiatry will be of much value. With such a background of knowledge he may be expected to guide the student in forming a real conception of the various mechanisms of the human body.

To Cornell University ]VIedical College, The Wistar Institute returns a grateful acknowledgment for a contribution of \$500.00 towards current expenses of The American Journal of Anatomy and The Anatomical Record.

A USEFUL MODIFICATION OF 2^1 ANN'S :METHYL BLUE-EOSIN STAIN 1

FRAXKLIX P. REAGAX From the Laboratory of Comparative Anatomy, Princeton University

Mann's methyl-blue-eosin stain has recenth' been found to be very useful in the differentiation of embryonic tissues, especially in the study of the vascular system. Skillful manipulation of this stain gives a brilliant red to developing blood-cells, while other tissues are stained deeply blue. The stain is especially favorable for the study of haemapoesis.

There are, however, certain defects in the original method. Constancy in the amount of differentiation in caustic alcohol is difficult to obtain; even different parts of the same embr^'o should be left in this reagent different lengths of time if a proper balance of red and blue be maintained throughout a given series. In the caudal region particularly it may be found that sections must remain for too short a time in caustic alcohol if enough blue be left in the tissue to be of greatest differential value. The nonvascular tissue is likely to possess a reddish color which cannot be removed by any reasonable amount of washing in chstilled or acidulated water. With eosin present in all the tissues it is difficult to judge the amount of methyl blue which is being removed by caustic alcohol. These objectionable features may be largely eliminated by a few simple alterations of method. TMiile these modifications have not received exhaustive trial, and while the stains so obtained have not yet been thoroughly tested for permanency, it is nevertheless true that they have afforded an astonislung degree and brilUancy of differentiation.

Sections are cleared in xylol, transferred through the alcohols to water, and then stained from fortv-eight to ninetv-six hours in Mann's mixture of:

One per cent aqueous solution of methyl blue 35 parts

One ]->er cent aqueous solution of eosin ' 45 parts

Distilled water 100 parts

Sections are rinsed in distilled water, then thoroughly dehydrated by direct transfer to ab.soluto alcohol, after which they are differentiated in caustic alcohol made as follows: To each 30 cc. of absolute alcohol

'Mann, G. Physiological histology, 1902, p. 216.

Grubler's aqueous eosin labeled 'W. GELBL' was found to be quite satisfactory. 401

402 FRANKLIN P. REAGAN

are added five drops of a 1 per cent solution of caustic potash in absolute alcohol. Sections are removed from this solution when they have acquired a reddish-purple color. FolloA\'ing this they are rinsed in absolute alcohol, and then washed in distilled water, which, according to the original method should be allowed to remove the eosin from all the tissues except the blood-cells. In my ovm experience I have found that the eosin is sufficiently removed ^\'ithin five minutes or less; then they are transferred to the folloA\ing mixture until over-stained:

One per cent aqueous solution of methyl blue 40 drops

Glacial acetic acid 30 drops

Distilled water 200 cc.

Sections are then washed in distilled water to remove acid, transferred to absolute alcohol, dehydrated thoroughly, de-stained in causticalcohol until the desired amount of blue is left in the tissue, rinsed well in fresh absolute alcohol, cleared in xylol, and mounted.

This gives the mesenchyme a clear blue, and the blood-cells varjang degrees of bright red, depending on their developmental stages. Ganglionic and glandular structures tend to retain the purple obtained by the original method. Xerve-fibers and cartilage may assume a pea-green color. Endothelium of vascular plexuses may be made to take on a denser blue than the surrounding mesenchyme, rendering a plainness rivaling that obtained by injection. Also it might be mentioned that in the original method, an adequate amount of differentiation in basic alcohol tends to remove all blue from blood cells and their nuclei, so that a given field might exhibit cells all of which would apparently be eosinophilous. In the suggested modification such blue is restored to the basophile cells and nuclei.

Further modification of the amount of methyl blue added to the acidulated water or of the acidulation itself may effect further improvement, yet the present modification leaves little to be desired.

^

o'>

THE MORPHOLOGY AND HISTOLOGY OF A CERTAIN

STRUCTURE CONNECTED WITH THE PARS

INTERMEDIA OF THE PITUITARY BODY

OF THE OXi

ROSALIND WULZE.V From the Hearst Anatomical Laboratory of the University of California

SEVENTEEN FIGURES

Certain physiological experiments are now being conducted in the Rudolph Spreckels Physiological Laboratory of this University which necessitate the separation of a great number of ox pituitaries into their two main divisions. As an interesting anatomical feature was in this way brought to our attention the material was used in addition for this anatomical study. This feature has not been mentioned by the following who have written more or less fully upon the pituitary bod}' of the ox, Peremeschko ('67), Dostojewski ('86), Herring ('08), and Trautmann ('11).

The pituitary body of the ox, like that of other vertebrates, is composed of two distinct portions. One, the pars nervosa, is derived from the brain as an outgrowth of the hypothalamus. The other originates as a hollow buccal evagination which in time is completely separated from the digestive tract. That portion of this evagination which comes into contact with the pars nervosa is called the pars intermedia. It is a comparatively thin sheet of epithelium which spreads as a coating over nmch

' Material amounting to thousands of pituitary bodies was most kindly supplied by the Oakland Meat and Paeking Company through the courtesy of the Superintendent. It was derived from cows, bulls and steers. .\s the cone structure was present indifferently in these throe varieties, its appearance can have little to do with se.\ or castration.

\{V,

THE ANATOMICAL RECORD, VOL. S, NO. S ACOUST. 19U

404 ROSALIND WULZEN

AHHKi:\IATl()NS

P.X., Pars nervosa CI., Cleft (residual lumen)

P.O., Pars glandularis I.S., Infundibular stalk

P. I., Pars intermedia B.S., Blood sinuses C, Cone

Cephalic

P.G.

Hg. 1 Tracing of a mid sagittal section of ox pituitary, natural size. The pars glandularis is caudad and ventrad, the pars nervosa cephalad and dorsad. The pars intermedia lies between the two but is separated by the cleft from the pars glandularis. Note the cone upon the pars intermedia and the cavity of the pars glandularis into which it fits, also the blood sinuses coursing through the pars glandularis toward the cone.

of the pars nervosa. The cells in the remamder of the evagination proliferate greatly to form the pars glandularis, the bulkiest part of the pituitary body. Between the pars intermedia and the pars glandularis appears the remnant of the lumen in the original evagination. This is the residual lumen or cleft of the pituitary body. Figure 1 represents these parts as they appear in mid sagittal section. I have taken the side of the pituitary toward the brain to be 'cephalic,' that opposite 'caudal,' the side toward the nose to be 'ventral,' that opposite, 'dorsal.'

The pituitary body lies in the sella turcica roofed with thick dura mater which is perforated ventrally by the opening which transmits the infundibulum. Just underneath this covering is found the pars nervosa, a flask-shaped structure with a long narrow neck, the infundibulum, jiassing to the brain through the aperture in the dura. The pars glandularis surrounds the pars nervosa throughout its length and enfolds it on either side to such an extent that its only free portions are its dorsal extremity and a strip of its cephalic surface in contact with the dura. The cleft of the pituitary body is easily opened for examination. It

PITUITARY BODY OF THE OX 405

is found to have the same shape as the pars nervosa and thus the broadest portion is close to the dorsal extremity. In the greater number of cases the two walls of the cleft are closely approximated, but sometimes they are spread widely apart by the liquid or solid material which gathers in the cavity. Occasionally the main divisions of the pituitary are so extensively attached to one another that the cleft is obliterated except in its ventral extremity around the neck of the pars nervosa.

In the cleft there is ahnost invariably found a mass of tissue attached to the pars intermedia but very different from it. This structure is usually s}Tnmetrically placed in the mid sagittal plane one-third or less of the way from the dorsal to the ventral end of the cleft. Its general shape is that of a cone one side of which may be longer than the other. The cones differ in proportion; some are broad and low, even flat, others are tall and narrow at the base. Rarely there are tv»'o cones. The following are the dimensions of a few:

mm. 7nm. mm.

2 2 5

7 5 4

4 3 2

2 3 4

3 3 2 3 2 2

They vary from such sizes as the above to specks so small as to be just visible. Rarely they are not to be seen. Thus out of 760 tabulated cases 38 showed no such structure. Probably almost all of the 3S would have revealed it liad a microscope been used. The writer has exaniineil at least five thousand of these pituitaries and has come to the conclusion that the cone structure in some fonn is practically always present. Sometimes the cone has the shape of a bulb which is connected by a slender stalk with the pars intorniedia, the whole structure being 8 or i) miii. in IcMigth. In these cases the bull) may be so deeply iinl)ed(le(l in the i)ars glandularis as to reach almost to its opposite extremity.

406 ROSALIND WULZEN

Figures 2 to 7 show typical fonns of the cone. The sections are approximately mid sagittal. By comparison with figure 1 their various parts may be easily identified. The bulkier and lower portion of each specimen is pars glandularis. The pars nervosa constitutes the larger part of the remainder. Between the two is the pars intennedia which is joined irregularly with the pars nervosa but is separated from the pars glandularis by the well developed cleft. Within the cleft is more or less colloid. Each spechnen possesses a well marked cone which occupies a corresponding depression in the pars glandularis but is in no way attached to it. In figures 2 to 5 the cone is finnly attached to the pars intermedia. In figures 6 and 7 a line of division runs all around the cone separating it from pars intennedia as well as from pars glandularis. Probably in these the cone is attached to the pars intermedia by a slight strand of tissue which would be shown in a different section. Many cones partly separated in this way from pars intermedia have been found.

Occasionally the cone is shifted in position to the dorsal end of the cleft. It thus comes into contact with the pars glandularis and may be finnly attached to it. Figures 8 to 13 are examples of this arrangement. The sections are similar to the preceding ones, the difference being that here the cone is firmly attached to pars glandularis. Figures 8 and 9 show a transition between the forms preceding and those following. The larger part of each cone is separated from pars glandularis by the cleft but there is nevertheless an area of firm attachment to the tissue of the pars glandularis.

In order that the remaining specimens may be understood, it is necessary to notice the arrangement of the blood sinuses of the pars glandularis. When a sagittal section of the pars glandularis is made it is seen to have a dark core arching toward the cleft. This is composed of large blood sinuses. Though present elsewhere in the glandular substance they are most prominent here. They often stretch through the gland as an almost flat sheet in the mid sagittal plane and go with surprising directness to the cleft where they come to the surface in the mesial line and distribute themselves with the greatest liberality <n^er the

PITUITARY BODY OF THE OX

407

Figs. 2 to 7 Approximately mid sagittal sections of ox pituitaries showing typical forms of the cone struct vire. Specimens wore hardened in Zenker, stained lightly with alum-oochineal, anil sectioned l\v hand. See description in text. Photograjjh X -. These and the following photographs were made by L. R. Newhart to whom the writer wishes to extend thanks.

surface of the depression into whicli the cone fits. In every specinuMi examined the rone projects into this most vascular portion of the pars glanihilaris. The hlood vessels are often so close to the surface in tliis region that they Meed with a touch.

40S

ROSALIND WILZEN

Mrs. fS to \:i SpcciiMcn.s prci):u('tl .similarly to those in liKiues 2 to 7. Tlicsc forms arc somewhat e\ee|)tional. See ilescri|)t ion in text. Photograph X 2.

Kig. 14 Mid sagittal section of ox pituitary in the region of the cone. Note the abrujjt transition between ])ars intermedia and cone, cellular debris in the cleft, and numerous blood sinuses in pars glan<lularis. Tlie band crossing cone and pars glandularis is an artifact. Section stained with Mallory's connective tissue stain. Photograph X 25.

Fig. 15 Description the same as for figure 14. Here the cone tissue does not project into the cleft but it is seen to be as distinct from the i)ars intermedia as in the former rase. Photograpli X 25.

14

15

400

410 ROSALIND WULZEN

In several of the specimens this core of l)lood vessels is distinctly seen as it travels to the exact location of the cone. In figures 10 and 11 the cleft appears only around the neck of the pars nervosa. The impression would be that there is no cone present were it not for the arrangement of the blood vessels. This is quite clear in both but is photographed most plainly in figure 10. Instead of arching to meet the pars intermedia at the apparent junction between pars intermedia and pars glandularis the l:)l{)()d sinuses come to an abrupt stop. In this way they mark out a large cone which is as well shaped as if it were separated completely from the pars glandularis by the cleft, no trace of which is here visible. In figure 11 the cone is marked out just as definitely. This also occurs in figures 12 and 13 but the outline of the cone is not so perfect, probably owing to incorrect section.

In color and consistency the cone is different from the pars intennedia. This difference which has been found to hold throughout the macroscopical examination is shown somewhat in the figures. The cone is composed of compact, creamy white tissue suggestive of the pars glandularis, whereas the pars intermedia is soft and more or less brown. The cone is often whiter and firmer than the pars glandularis itself.

HISTOLOGY

Pituitary bodies were fixed in Zenker's, Bensley's or Orth's fluids, were sectioned sagittally and stained with hematoxylin and Congo red, eosin and methylene blue, or Mallory's connective tissue stain. Ten specimens were examined. Of these eight showed the cone structure undoubtedly present, and in one it was probably lost through poor technique. Figure 14 shows the cone i)rojecting from the pars intennedia into the hollow of the pars glandularis. The cleft separates the two. That the tissue of the cone differs markedly from pars intermedia can be seen at a glance, the transition between the two being well marked. Figure 15 is a similar section of another specimen. The cleft runs through the center separating purs intermedia above from pars glandularis below. Here the cone tissue is raised only

PITUITARY BODY OF THE OX 411

slightly from the surface. It is, however, a fairly definitely circumscribed area which is striking!}' different from pars intermedia. Even when the cone was so small as to be composed of a few cells only, its apearance was unmistakable. Greater magnification reveals the reason for the difference. Cone tissue contains as its most striking characteristic, deeply staining acidophile cells with coarsely granular protoplasm which are apparently identical with those of the pars glandularis. As far as I have been able to detemiine, acidophile cells have never before been noticed so closely associated with the pars intermedia. Indeed, Herring ('08) says The intermediate portion, although derived from the same source as the main anterior lobe (pars glandularis), differs from it in adult mammals in that it contains no eosinophile cells." Tilney ('11) joins him in the remark, The juxta-neural epithelial portion (pars intermedia) is invariably basophilic. These statements have great weight in that both investigators have made careful examinations of the pituitary bodies in many different animals. The remaining cell elements of the cone are similar to those of the pars glandularis. But certain differences exist which, though perhaps of slight importance, make it possible to distinguish between pars glandularis and cone tissue. The connective tissue septa are finer and the interstices are ordinarily smaller and contain fewer cells in the cone than in the pars glandularis. On this account the grouping of the cone cells into acini may appear to be lacking, while the acini of the pars glandularis are apparent at a glance (figs. 10 and 17).

One of the specimens examined was found to resemble the condition shown in figures 10 and 11. The cone was finnly joined to pars glandularis as well as to pars intennodia. Microscopically it showed itself to be as typical a cone as any of the others. A definite connective tissue septum out fined the surface of the cone, adjacent to the pars glandularis. Its tissue differed in the same manner as the other cones from the surrounding tissue of the pars glandularis.

It is noteworthy that in the only specimen in which the cone was actually lacking the cleft was very small, appearing only

412 ROSALIND WULZEN

around tlio neck of the pars nervosa. The pars intennedia over-lapi)od the cleft at its dorsal end and spread irregularly some distance into the pars glandularis. Also large portions of the jiars glandularis had the characteristic a})pearance of cone tissue, that is, the acini had few cells and were separated by very fine strands of connective tissue. In no other specimen did the pars glandularis have this appearance.

jMicroscopically the vascularity of the cone appears to be slight but in spite of this when the cleft of a fresh specimen is opened the cone is often flushed with blood. The bloodvessels appear to be superficial and are spread mainly about the base of the cone.

This preliminary work leaves many problems unsolved. \Miat are the phylogenetic relationships of this very constant structure? Can any light be thrown upon it by the study of its development? Has it any physiological significance? If this study suggests anything it suggests a closer relationship between pars glandularis and pars intennedia than has hitherto been suspected. The distribution of the blood sinuses of the pars glandularis about the cone is often so striking that it is impossible to avoid the impression that such an appearance cannot be an anatomical chance. Thus when the cone penetrates deeply into the pars glandularis, the walls of the cavity into which it is so closely fitted are solidly packed wdth blood sinuses. This would a])poar to be an excellent arrangement for the absorption into the })lood stream of any secretions from the cone or pars intennedia. Certain color changes should also ])e mentioned in this connection. The pars intermedia is ordinarily distinctly tinged. It assumes all colors between dull white and bright orange or yellow or brown. The pars nervosa never shares its color. It is a uniform dull white. On the other hand the i)ars glandularis may have its characteristic creamy or

Figs. 10 and 17 iJctail from t lie six'ciincii sliown in tinurc 14. Figure 10 sho\v.s typical ti.ssuc of the cone, fip;uro 17 typical tissue of pars glandularis. Note the prominence of the deeply staining acidophile cells in both, but observe that in the pars glandularis the acini are more prominent and the connective tissue septa are broader. Photograph X 275.

16

' «*•

t^fj

17

413

414 ROSALIND WULZEN

grayish white appearance when the pars intermedia is brightly colored or it may share the coloration of the pars intennedia. Thus it too is sometimes a deep orange. It, however, has never been observed to be highly colored unless the pars intermedia as well is brightly colored. This also suggests a common activity of pars intermedia and pars glandularis or some interrelation between them. Work is being carried out along the lines suggested.

Acknowledgment is due to Dr. P. E. Smith for his kindly help.

CONCLUSIONS

1. A structure of more or less definite cone shape appears constantly upon the pars intermedia of the ox pituitary.

2. Its cellular elements resemble those of the pars glandularis. Numerous acidophile cells are its most striking feature.

3. It differs from pars glandularis through having in a general way finer connective tissue septa and smaller acini.

BIBLIOGRAPHY

DosTOiEwsKi, A. 1880 t^ber den Ban dcs ^'or(lerlapl)ens des Hirnanhangs. Arch. f. niikros. Anat., Bd. 26.

Herring, P. J. 1908 The development of the mammalian pituitary and its morphological significance. Quart. Jour. Exper. Phys., vol. 1. 1908 Histological appearance of the mammalian pituitary. Quart. .Jour. Exper. Phys., vol. 1.

Pkrkmkschko 1867 Ubcr den Bau des Hirnanhangs. Virchow's Arch. f. path. Anat. und Phys. und klin. Med., Bd. 38.

Tii.NKY, F. 1911 Contribution to the study of the hypophysis cerebri with especial reference to its comparative histology. Memoirs Wistar Inst. .\nat. and Biol., No. 2.

1913 An analysis of the juxta-neural epithelial portion of the hypophysis cerebri, with an embryological and histological account of a hitherto undescribod part of the organ. Intern. Monatsschr. f. Anat. und Physiol., Bd. 30.

Tratttma.w, a. 1909 Anatomie und Histologic der Hypophysis cerebri. Arch, f. mikroH. .\nat., Bd. 74.

OSSICULUM LUS

J. C. MILLER

Frotn (he Anatomical Department, Western Reserve University, Cleveland, Ohio

Some reference to this mysterious bone is found in all anatomies of ancient times and in those of the Middle Ages. The name itself is derived from the Hebrew 'luz' (almond), Arabian, 'lauz.' Its histor>' may be of some interest.

In the Old Testament (1) we find the following passage: "Castodit Dominus omnia ossa justorum — -unum ex illis non confrigetur." In the English version we read: Not one of them is broken," but there is no emphasis on the 'one,' nor need it mean, as the Latin renders it, "there is one which .shall not be broken," for had the Hebrew writer meant simply to sa}'. "none of his bones shall be broken," he would have stated it in the same manner. Reference to both Lsaiah, xxxn'. 16, and Psalm cvi, 11, .shows the use of the .same idiom. In neither of these passages is it to be understood that a particular one (bird or enem}') is missing.

Further, we may say that not merely may Psalm xxxiv. 20. be translated as in the English version, but that it must l)e so translated. The two clauses of the verse, as so often in Hebrew poetry-, contain parallel ideas, simply repeating the same thought in different words, thus:

He keepcth all his bones, Xot one of them is broken.

In this psalm tiiere is no thought of any life after death. It is in this life that God preser\'es the righteous. Xeverthele.ss, the possible alternative translation of the Hebrew affords a point for argument, and it is probal)le that tlio rabbinic mind, aj^t to controversy, has raised the que.>^tion whether or no the tran.-^lation sliould l)e 'one of them' with the emi)liasis on the 'one.' thereby stimulating the search for the 'unum os' now well-known as the 'os luz.

The learned Rabin Uschaia (2), who lived in the third century- .\.d., tlefined this bone as in fine octodecim vertebrarum." Xot only Uschaia. but other writers (especially the anatomists of the School of Salenio) have giv(M) the numlnM" of vertebrae as eigliteen (3): "Sunt autem octodecim s|K>n(lilia, in colic sex, in dorso duodecim." According to Haller (4) the lumbar vertebrae were not considered vertebrae proper, because tiiey do not enclose any part of the spinal cord, but only the cauda ecjuina of tlu> talmudists. Even at that, as Hyrtl (5) remarks, the number of vertebrae would be 19 and not IS.

' For help in the transh\tion and interpretation of the literal Hebrew. I woul Hebrews, in size but that of a. pea, touched by no decay, nor concjuered l)y the fire, will remain imblemished forever; from it, as a plant from the seed, f)ur ])odv shall arise hi the resurrection of the Dead," which

OSSICULUM LUS 417

sentence he ends with these remarkable words: Et hae virtutes non declarantur ratione, sed experientia;" ("Os minimum, fiuod Hebraei Luz appellant, magnitudine ciceris mundati, nulli corruptioni obnoxium, nee igne quidem vincitur, sed semper conversatur iUaesum, ex quo, velut planta ex semine, in resurrectione mortuorum, corpus nostrum repullascet").

An editorial in the Lancet (9) refers to this bone as the twelfth dorsal vertebra, "the turning point and centre of the spine." Although no reference is made to the source of this information, I think the quotation is taken from Galen, who in all proljability dissecterl onh' animals, and it would thus refer to the 'anticlinal' vertebra.

Since this remarkable bone could not be found in fine octodecim vertebrarum," search was begun elsewhere. The skull as an important part of the body attracted attention first, and the supernumerary- bone, frequently found at the junction of the sagittal and lambdoidal sutures (perhaps the os interparietale or os Incae?j was thought by some to be the 'os lus.' Many virtues were attributed to this bone, and its remedial powers were supposed to be great, especially when it came from the skull of an executed criminal. According to HyrtI (14), the pulverized bone was first used as a remedy for epilepsy by the Swiss physician Hochner, who latinized his name to Paracelsus, and hence the term, ossiculum antiepilepticum Paracelsi.

A similar term was used in reference to the os epiptericura ( Virchow ) OS epilepticum, which, according to Lombroso. is always to be found in delinquent and demented people (23).

But not all skulls have these epactal bones, and thus other writers looked for it at the l)ase of the skull, as Hieronymus Magius ( 10) tells us, without stating, however, which bone it is. According to Bauhinus (I.e.), the seventh cer\'ical vertebra, the vertebra prominens: according to Dassovius (11), the os coccygis was taken for the 'ossiculum lus.' The explanation of Dassovius is ver>' probably ba.sed upon the Arabian name for cocc^-x, 'al ajab' (al ajas), '^' which Mohammed stated to be incorruptible and to ser\'e as the basis for the future edifice" (9).

The same author (9) informs us that the os sacrum was thought to be the 'os lus' '"on account of its old name iepoi- boTtov but here the author makes the same mistake which many others made before him. Isidorius (12) gives the following explanation of the os sacrum: '"Ima spinae pars, quam CJraeci hpbv oarovv vocant, quia primum in infanti nascitur, ideoque et ho.stia a gentilil)us diis suis dabatur."

The word 'sacer' is explained l)v Festus ( 13) in the following manner: (lallius Aelius declares sacred (sacer) that which in any manner is dedicated to the state, whether house, altar, e:igle. riches or anything dedicated and consecrated to tlie gods." ("(lallius Aelius ait. sacrum esse quoquun(iue modo at(iu(> instituto civitatis consecratum sit. sive aedis, sive ara, sive sigiuun. sive p(>cunia. sive (|uid aliud diis dodic;itura atque consecratum sit'i.

^Iarcus Aurelius: .Vn^-thing set apart for the gods is tennetl sjicre«i (sacer);" and Sacred (^ sacer) are tho.>*e things which have been conse

418 J. C. MILLER

crated to the gods above;" ("Quidquid destinatum est diis 'sacrum* vocatur;" "Sacrao (res) sunt quae diis superis consecratae sunt:" Institutiones juris civilis).

All these deftnitions of 'sacer' do not explam the 'sacrum' in 'os sacrum;' there are, however, other possi])le explanations: The first is contained in the statement made by Hyrtl (14), that the 'os sacrum' is simply an erroneous translation of the (ireek lepop barkov.

1. The Greek term for 'os sacrum' was (nrovbvKo^ jikyas or tepos ioarkov ukya or lepbv), where up6% has tlie meaning of 'magnus;' thus Homer uses "IXtos Ipi) and iepos ttovtos (for "IXtos /jLeya'Kr] and iJikyas woutos). Spigehus (15) says: Graecis omnia magna 'sacra' vocabantur;" and Caelius Aurelianus (16): "Majora omnia vulgus 'sacra' vocat."

2. There is, however, in Latin itself an explanation of 'sacer' which seems to me preferable and more plausible, namely, its meaning 'detestable,' as we find it in the Leges xii talnilarum: "That man is anathema (sacer) whom the people have found guilty of a crime; and "an advocate shall be detestable (sacer) who defrauds his cUents"; (Homo 'sacer' est (luem populus judicavit ob maleficium;" and "patronus qui clienti fraudcm fecerit 'sacer' esto" (ibid).

According to this definition of 'sacer,' 'sacrum' would be the equivalent of 'detestandum,' and the bone received its name 'sacrum' (i.e., detestandum) from its lieing near the rectum (obscoena).

3. In addition to this Garrison (17) quotes Ramsbotham (18), who suggests that lepov in connection with the sacrum is not the Greek Upov, Ijut a corrupted form of the Hebrew 'iieron,' signifying conception, parturition, whence also Hera, the goddess of childbirth.

Garrison (1. c.) also produces some evidence that the external sesamoid bone of the great toe was thought by certain authors to be the 'ossiculum lus.'

Lastly, the inner, larger sesamoid Ijone of the Articulatio metatarsophalangea hallucis was selected as the os resurrection is on account of its real hardness and its form (seed of the sesamum) ; it is mentioned by Vesalius (17), Riolanus (18) and Bartolinus (19) under the name 'albadaram,' and as such it played a great role "apud magiae et occultae philosophiae cultores."

The OS sacrum, however, as the mysterious ossiculum lus, has found its place in history in the 'rump parliament,' as may be seen in the following quotation from Butler (22) :

The learned Rabbis of the .Jews Kroin whcnco the learned sons of art

Write there is a bone they call Luz Os sncrum justly style that part,

r the rump of man, of such a virtue, Then what can better represent

Xo force of nature can do hurt to: Than this Rump Bone, the Parliament

And therefore at the last great day That after several rude ejections,

.Ml th' other members shall, they say, And as prodigious resurrections,

Spring out of this, as from a seed With new reversions of nine lives

All sort of vegetals proceed: Starts up and like a cat survives?

OSSICULUM LUS 419

I^ut the naine lias disappeared from anatomical text-books, and the word remains in our dictionaries only as a reminder of theTinatomy of times past.

(1

(2

(3

(4

(5

(6

(7

(8

(9

(10

(11

(12

(13

(14

(15

(16

(17

(18

(19

(20

(21

(22

(23

REFERENCES Psalm xxxiv, verse 20.

Uschaia: Bereschit rabba (glossa magna in pentateuchum;. Magistuar Ricardus: Codex anatoinicus, p. 23. Haller: BibHotheca anatomica, T. 1, 2, p. 126. Hyrtl: Das Arabisc-he und Hebraische in der Anatomic, p. 166. Bauhinus: Theatrum anatomic-urn, Lib. 1, cap. 48.

Rolfink: Dissertationes anatomicae, Lib. 2, cap. 54: De ossibus sesamoideis. CoRXELius Agrippa: De occulta philosophia. Lib. 1, cap. 20. The 'Os Luz'. Lancet, vol. 2, 1910, p. 1029.

HiERONYMUS Magnus: De mundi exustione et die judicii, Lib. 5, cap. 1. Dassovius: Tractatus de resurrectione mortuorum, cap. 3, p. 23. LsiDORius: Etymologicorum. Lib. 2, cap. 1. P'estus: De verborum significatione (letters M-Vj ed. Miiilcr. Hyrtl: Lehrbuch der Anatomie, pp. 285 and 324. Spigeliu.s: De corporis huraani fabrica, Lib. 10. Caelius Aureliaxus: De morbis acutis, Lib. 1, ca[). 4. Garrison: The bone called 'luz,' New York Med. Jour., vol. 92, p. 147. Ramsbotha.m: Obstetric medicine and surgery, p. 698. Vesalius: De corporis humani fabrica. Lib. 1, cap. 28. RioLANus: Commentarius in Galeni librum de ossibus, cap. penult imum. Bartholixcs: Institutiones anatomicae. Lib. 4, cap. 22. Butler: Huriibras, Part 3, canto 2, 1. 1915. Le Double: Traite des variations des os tlu crane, p. 306.

THK ANATOMICAL RECORP, VOL. 8, NO. 5

The receipt of publications that may be sent to any of the five biological journals published by The Wistar Institute will be acknowledged under this beading. Short reviews of books that are of special interest to a large number of biologists will be published in this journal from time to time.

Psychology in D.\ily Lifk (Conduct of the Mind Series, edited by Joseph Jastrow), by Carl Emil Seashore, Professor of Psychology and Dean of the Graduate College in the State University of Iowa. 226 pages, New York. 1914, D. Appleton and Company', ?1.50 net.

Publisher's Announcement. This volume well represents the general purpose of the Conduct of Mind series which is, to present for the intelligent reader the several aspects of mental affairs which are involved in the regulation of practical interests. The volume comprises a selection of illustrative material with their interpretation, and may well serve as an introduction t* the stud}' of psychology. It proceeds bj' selecting a few general topics rich in application and about which a considerable range of mental principles may be grouped. The several chaptcr.s deal with toi)ics such as Play, The Law in Illusion, Mental Measurement, Mental Health and Mental Efficiency. The illustrations are in each case given a sufficient setting so that they become typical of the problems of psychology and at once suggest how competently the 'ssues of our daily life are conditioned b}' the psychological basis. The work is free from technical terms and presents a fresh and original arrangement of the material characteristic of modern interest in the laws of the mind.

420

PERSISTENT ARTERIAE BRACHII SUPERFICIALIS, ANTIBRArHII SUPERFICIALIS ET MEDIAXA

E. R. HOSKINS FTom (he Inslilute of Anatomy, University of Minnei^ota

OXE FIGURE

An unusual artery found in the left arm of a man of thirtj'-seven years seems? worthy of record.

The vessel emerges from the axillaris midway between the aa. subscapularis and thoracalis lateralis, on the median side. It runs in the deep fascia anterior and medial to the a. axillaris, the a. brachialis and the n. medianus, almost to the middle of the humerus, where it crosses the a. brachialis and the n. medianus, to enter the m. biceps brachii from beneath, through two large divisions.

It gives off two small cutaneous rami in the lower axillary' and upper brachial regions. In size the artery is about twothirds that of the nonnal subscapularis until it reaches the biceps muscle. At this point it gives rise to a small ramus almost at right angles to it. This courses lateral ami anterior to the biachial artery in the deep fascia, becomes superficial at the elbow, and continues anterior to the ulna, to the palm. Here it enters into fonnation of the arcus volaris superticialis. together with the a. ulnaris. The arch has no connection with the a. radialis.

There is no ranuis of the :i. ulnaris or a. interossea which may l)e called an a. mediana. The a. mediana descril>ed in this paper has no relation to the n. nK^dianus. wliich is placed deep in the forearm.

The embryological signilicance of the artery in question may be derived from Midler's' figiue of the arteries in the ann of an

'Miilirr '(W. Anal, llt'ftc. H.l. iJ. T.if. 2.")-2('.. fig. 0.

4J1

422

E. R. HOSKINS

Fig. 1 Persistent artcria; biachii superfiicialis, antibrachii superficialis et incdiaiia. The rami of the aa. brachialis, radialis and ulnaris are not shown in the figure, as they are normal excei)t for the two discrepancies noted.

11.7 111111. human embryo ('03). From this fijiuro it would soom that we have a persistent a. brachiahs superliciahs, giving rise to an a. antibrachii superficialis, which becomes an a. mediana, but all anastomoses with the a. brachialis have been lost. As stated by some texts of anatomy, this condition is one that is (luite rarely found.

THE MICROSCOPIC STRUCTURE OF MAMMALIAN

CARDIAC MUSCLE WITH SPECIAL REFERENCE

TO SO-CALLED MUSCLE CELLS

H. E. JORDAN

From the Anatomical Laboratory of the University of Virginia

EIGHT FIGURES

In recent histologic descriptions of the mammaHan heart the muscle is more conmionly regarded as a syncytium. The unifjue characteristic of heart muscle is the presence of intercalated discs. The earlier interpretation that these discs mark cell boundaries has been most recent h" championed by Zimmermann fl). That cardiac muscle, however, can not be regarded as composed of cells separated from one another by 'intercellular' intercalated discs I have attempted to prove in a recent series of papers (2, 3, 4, 5). The salient observation among the countervailing facts recorded concerns the occasional supernuclear position of these 'discs.'

In 1888 Apathy (cited from Lewis, 6) advanced the interpretation that striped muscle, inchuling heart nmscle. was structurally comparable witli the connective tissues, consisting of cells and extracellular bundles of myofibrillae. Recently Baldwin (7, 8) has attem])ted to establish this hypothesis u])on a basis of cytologic observations, and concludes that voluntary striped muscle generally, and cardiac muscle of the adult white mouse, consists of distinct nuiscle cells, and extracellular columns of muscle fibrils and sarcoplasm enveloped by sarcolenuna. The 'cells' are described as lying outside the sarcolemma.

If Baldwin's conception of cardiac nuiscle is correct, then his observations contribute one (^f tlic^ strongest objections to any interpretation that ccMisiders tlie intercalated discs ns intercellular structures marking cell l)oun(laries.

THE ANATOMICAI, UECDni). VOL. 8, NO. '.•

sv:rTv:Miu:u. I '.114

424 H. E. JORDAN

I shall concern myself Ikmo chief! 3' with Baldwin's conception of striped muscle structure as it pertains to cardiac muscle, my special interest l)eing enlisted by reason of its bearing on the nature of the intercalated discs.

Baldwin used only sectioned material. The essential point in his proof that there are 'muscle cells' pertains to the presence of a delicate 'cell membrane,' separating a nucleus with an envelope of cytoplasm from the myofibrils hnbedded in a distinct sarcoplasm. Such conclusion presupposes very delicate observations. One must guard against fixation artefacts and misleading appearances due to obliquity of section. Obviously from this standpoint macerated tissue is preferable to sectioned tissue. In macerated preparations one can examine considerable lengths of single muscle trabeculae, and by careful focussing thus view exact median longitudinal sections (optical) of 'fibers/ obviating all errors due to obliquity of section. Also, in properly preserved specimens shrinkage is prevented; and even a fair degree of dififerential staining can be obtained.

For the purpose of my study I employed principally dissociated tissue of fresh cat's heart; also macerated tissue of previously fixed (in Carnoy's fluid) heart of white mouse. I had on hand also abundant sectioned and stained material (treated according to Zimmenuann's technic) of various mammals, and of heart of aduh white mouse (Carnoy's fixation ; iron-hematoxylineosin stain) for additional study.

The cat tissue was macerated in a saturated solution of potassium chlorate in nitric acid and preserved in a mixture of equal parts of water, 95 per cent alcohol and glycerin. Many stains, both cytoplasmic and nuclear, and various combinations of stains were employed. The best results were obtained l)y use of borax cannine or eosin in xarious degrees of concentration.

That the method of treatment does not seriously injure the tissue for detailed observation is indicated by figure 1 which purports to be an accurate representation of actual appearances in lli(> median longitudinal plane. The .sarcolemma is well preserved as shown in the lower portion of tlie illustration where it is festooned between .succes.sivc tcl()})iiragmata (Krause's

MAMMALIAN CARDIAC MUSCLE

425

Fiji. 1 -Muscle fiber of cat's heart from macerated preparation, showing two nuclei connected by a continuous axial strand of coarsely granular sarcoplasm. The drawing represents appearances in the optical median longitudinal plane. There is no evidence of a cell membrane separating the central granular from the peripheral non- or finely-granular sarcoplasm. X 1500: reduced one-third in reproduction.

Fig. 2 Median longitudinal section of muscle fiber from ventricle of adult white mouse showing three nuclei imbedded in a continuous axial strand of coarsely granular sarcoplasm. The specimen was fixed in Carnoy's solution, and stained with iron-hematoxylin and eosin. X 1500; reduced one-third in reproduction. The destaining process is here carried too far to show the intercalated discs.'

' Fixation in Carnoy's strong solution (acetic alcohol with chloroform^ followed by iron-hematoxylin staining, is a good technic for demonstrating intercalated discs. This metiiotl brings out siiarply also the Q-substance and the Z-linos. The phase of contraction is thus clearly shown. For a study of the relation of the discs to 'contraction bands" it seems preferable to any of the special methods fi>r intcnubiftMl discs.

4'2() H. E. JORDAN

iiioinl)i-aii('s, of Z discs). In tlie ui)i)('r i)()rtion of the figure the festooning does not appear. From the standpoint of the niyofihrils the fiber differs in (hfferent regions. In the mid-portion, which is constricted (contracted), the fibrils are coarser and show a distinct alternation of Ught and dark bands (discs). In these same regions also the telophragmata are much coarser. The coarsei' telophragmata and the darker discs of the stouter fibers are identical, and represent 'contraction bands of Rollct.' The nuclei are clear with sharp contour, each surrounded by coarsely granular cytoplasm. The technic has clearly preser\'ed such delicate structures as sarcolenuna, differences between contracted and relaxed portions of the fiber, nuclear wall and reticulum, and cytoplasmic (sarcoplasmic) reticulum and granules.

But in face of these facts no definite indication of a cell membrane appears. The perinuclear sarcoplasm shades away into the peripheral fibrillar and finely granular sarcoplasm without sharp line of demarcation except such as is simulated at certain levels of focus by adjacent myofibrillae. ^Moreover, one perinuclear cone of sarcoplasm connects with adjacent cones through narrow strands of structurally similar sarcoplasm. In sections of such trabeculae a slight obliquity of cut would give an entirely false impression. This observation of a continuity of axial undifferentiated sarcoplasm, swelling at the levels of the nuclei, can be made onl>' Aery rarely in sectioned tissue. However, figure 2 shows a similar condition in a section of ventricle of adult white mouse. In cross-sections of cardiac nmscle of various manunals such a central core is almost invariably discernible, though frequently so frail as to escape notice unless specially looked for.

The undifferentiated sarcoplasm fonns an axial granular covo: the telophragmata extend thiough it, though frequently somewhat irregularly, as can be clearly observed in tissue deejily stained with iron-hematoxylin. There is no evidence warranting a distinction between the perinuclear plasm as cytoplasm, and the myofibrillai- portion as sarcoplasm. No clear evidence appears of a cell membrane in macerated tissue; in fixed tissue an adjacent myofibril, not showing a clear alter

MAMMALIAN CARDIAC MUSCLE 427

nation of light and dark discs, or a condensation (fixation artefact) of peripheral protoplasm, may simulate a cell membrane. Such apparent 'cell membranes' can frequently be traced at some distance into an undoubted fibril. Xor is there any indication of the complicated investment of sarcolemma with respect to myofibrils as conceived by Baldwin. The main observations, however, arguing against Apathy's original conception are the continuity of the axial strand of granular undifferentiated sarcoplasm, and the continuity of the telophragmata throughout the extranuclear portion of the muscle.

But granted that fusiform heart muscle cells actually do exist as illustrated by Baldwin: such cells should then appear isolated in properly macerated material. On the contrary one finds only such short fragments as illustrated in figure 3. Fractures occur in the macerating fluid along the telophragmata, frequently at the levels of the intercalated discs. Such fragments suggest a close structural association between the granular perinuclear sarcoplasm and the non-granular sarcoplasm among the fibrils, most proba))ly by virtue of the telophragmata as first described by MacCallum (9). "VMien the maceration has progressed further only naked nuclei appear (fig. 4), with small adherent masses of sarcoplasm. Occasionalh' such a structure as illusrated in figure 5 appears. Here a i^erijiheral coarse fiber-structure simulates a portion of a cell membrane. But usually its striped character reveals its myofibril nature.

That the technic does actually isolate cells when present is shown by abundant spindle shaped cells (fig. 6) from the endomysium. If the nuiscle nuclei and spindle shaped areas of enveloping sarcoplasm actually' constituted spindle shaped colls surrounded by a membrane, the same technic which isolated such structures from the connective tissue of the same material would also be expected to isolate them from the muscle comjilex. The hypothetical spindle shaped cell of cardiac muscle is obviously structiu'ally not closely similar to the fusiform cells of the endomysium, or of smooth iiuisclo.

Smooth muscle from tlie intestine of the cat subjected to an identical technic vields the usual fusifonn cell, enclosed in a

Fig. 3 Fragment of fiber from macerated cat's heart, drawn as if it were a transparent object. The nucleus is surrounded by granuhir sarcoplasm. The breaks follow tclophragmata, without any relation to hypothetical cell membranes. The manner of fracture strongly indicates that the central granular and more peripheral non-granular sarcoplasm are continuous, probably by reason of the meso- anrl tclophragmata. and that the former is not invested bj^ a cell membrane. X 1.500. •

Fig. 4 Naked nucleus from similar ])rci)arati()n. with adherent clumps of sarcoplasm.

Fig. Nucleus with an adherent mass of graiudar sarcoi)lasm from Ihc same preparation. The sarcoplasm is delimiteil at the right bj' a stout fibril which simulates a membrane, but a faint segmentation reveals its true myofibril nature.

Fig. 6 I.solated fusiform connective tissue cell of the endomysium from the same preparation.

Fig. 7 Isolatcfl large fusiform smooth muscle cell from cat's intestine. The nucleus is surrounded by coarsely granular sarcoplasm as in cardiac muscle, which is continuf)Us similarly with the more peripheral non-granular or finely granular sarcoi)lasm, though myofibrils may simulate, as in heart muscle, a cell membrane. X 1500; reduced one-half in reproduction.

Fig. 8 Oblique transverse section of smooth muscle cell from nuiscularis mucosae of esophagus of cat. The perinuclear sarcoplasm has contracted away from the nucleus leaving a clear space, peripherally limited by a sharp line, a fixation artefact, simulating a cell membrane. The light-blue-staining sarcoplasm however is peripheral to this 'membrane' Zenker's fixation; hematoxylineosin stain. X 1500.

42S

MAMMALIAN CARDIAC MUSCLE 429

distinct nieiii})ran(\ The centrally placed elongate nucleus is enveloped by undifferentiated granular sarcoplasin in a like manner, and of apparently identical structure, even to a delicate peripheral 'membrane,' as in cardiac muscle trabecular Further mechanical treatment (teasing) separates a similar essentially bare nucleus. Fixed smooth muscle stained with the hematox\'lin-eosin combination shows the central perinuclear mass of sarcoplasm stained a faint blue, in contrast to the deep blue of the nucleus and the bright red of the cytoplasm. Certain cells show contraction artefacts. In these cases a space, empty, except for occasional very delicate strands, appears between nucleus and contracted cytoplasm. The inner surface of the latter exhibits a sharp contour, simulating a delicate membrane.

In cross-sections one finds appearances like figure 8 (oblique section of smooth muscle fiber of muscularis mucosae of esophagus of cat). Occasional strands spanning the space might be interpreted as spongioplasm; but the space is colorless, while the light-blue-staining sarcoplasm is without but closely applied (indicating contraction) to the peripheral border or 'membrane' of the space.

If cardiac muscle can be appropriately interpreted in terms of fusiform cells and extracellular masses of myofibrils and sarcoplasm, smooth muscle should be similarly interpreted, since apparently exactly the same cytologic conditions as regards nuclear relation to sarcoplasm prevails in both, irrespective of course of telophragmata. But the histogenesis of smooth nmscle renders such interpretation very improbable. ^Moreover, maceration separates the genetic units, not secondary structures. Shnilarly in the case of cardiac muscle: genetically we start with a syncytium in which myofibrillae are dejiosited: maceration separates irregular fragments, and ultimately yields naked nuclei and masses of myofibrillae imbedded in sarcoplasm. Since the intercalated discs, locations wIumv fragmentation frequently takes place, can not be regarded as cell boundaries, the cardiac muscle must be conceived to persist in its original syncytial condition.

430 H. E. JORDAN

The results of this study of cardiac muscle by the dissociation method, and comparative observations of snnilarly treated endomysium and smooth muscle tissue, yield no evidence in favor of the cellular conception of heart muscle suggested by Ai:)athy and supported by Baldwin. On the contrary heart muscle appears to l)e a true syncytimn, the anastomosing nmscle trabeculae consisting of axial strands of undifferentiated coarsely granular sarcoplasm containing nuclei, and peripheral layers of ai^parently non-granular or finely granular sarcoplasm differentiated in that it contains myofibrillae marked by alternating dark and light discs and intercalated discs, the telophragmata being continuous throughout the extranuclear muscle complex.

LITERATURE CITED

(1) ZiMMEK.MANX, K. W. 1910 t'ber den Bau tier Herzmuskulatur. Arch. f.

mikr. Anat. u. Entwickl., Bd. 75, no. 1.

(2) Jordan, H. E. 1911 The structure of heart muscle of the humming bird,

with special reference to the intercalated discs. Anat. Rec, vol. .5, no. 11.

(3) Jordan*, H. E., and Steele, K. B. 1912 a A comparative microscopic

study of the intercalated discs of vertebrate heart muscle. Am. Jour. Anat., vol. 13, no. 2.

(4) .JoRDA.N, H. E. 1912 The intercalated discs of hypertrophied heart muscle.

Anat. Rec, vol. 6, no. 9.

1012 The intercalated discs of atrophied heart muscle. Proc. Soc. Exp. Biol, and .Med., vol. 10, no. 2. (.5) Jordan, H. E., and Bardin, J. 1913 The relation of the intercalated di.scs to the so-called segmentation and fragmentation of heart muscle. Anat. Anz., Bd. 43, pp. 23 and 24.

(6) Lewis, F. T. 1913 Textbook of histology. Philadelphia; p. 128.

(7) Baldwi.v, VV. M. 1912 The relation of muscle cell to muscle fiber in volun tary striped muscle. Zcits. f. .\llgem. Physiologic, Bd. 14. 1912 b .Muscle fibers and muscle cells of the adult white mouse heart. Anat. Anz., Bd. 42, 7 and 8. <9) SzY.MONOwicz, L., and MacCallu.m. J. B. 1902 Textbook of histology. Philadelphia; p. 86.

THE THYROID GLAXD OF THE OPOSSOI

R. R. BEXSLEY From the Hull Zoological Laboratory, University of Chicago

THREE FIGURES

In the thyroid glands of several of the opossums obtained in the autumn of 1912 from New Jersey several features of interest were noted, which may be briefly stated as follows : The th\Toid epithelium, instead of being uniform, as is usual in vertebrates, contained, in addition to the usual tj-pe of ei)ithelial cells, ovoid cells, parietal in position with reference to the foUicles. filled with fine eosinophile granules which gave them a striking resemblance to the oxyphile cells of the anterior lobe of the h^-pophysis. The epithelium of the thyroid follicles contained large needle-shaped crystals. The th\Toid glands of those animals which were kept in the laborator}' for two weeks or longer showed a high degree of hyperplasia, associated with the disappearance of the contents of the follicles and of the crystals and, in those kept for a longer period, the appearance of a new secretion antecedent in the form of granules along the free border of the cell.

Shice it was possible, considering the time of year at which the collections were made, that the characters and changes in question were associated in some way with the phenomena of hibernation. I made preparations to obtain a larger number of animals, during the past winter, in small groups caught at different parts of the season, and immediately shipped to the laboratory. I have been able to secure these, through the aid of Mr. Ell^ert Clark, from ^^ aldo, -Vrkansas. From each of these series, received on October 21, 1913, December 5, 1913, December 22, and January 19. one or more animals were examined immediately, while others were kept for varying lengths of time in the laborat<M'v. and then examined, or were usetl for experiments as indicated later.

431

432 H. U. HENSLEY

Tlie tliyroids of all animals examined immediately after their arri\al at the laboratory showed the normal type of gland. There were minor variations in the size of the vesicles and in the shape of ej)ithelial cells. ])ut, in all, the follicles were well formed and spherical and filled with a deeply staining colloid. In all the animals also the ovoid cells mentioned above were present in large numbers, and large crystals occurred in the cells of the follicular epithelium.

The thyroids of the animals examined two or more weeks after their arri\al at the laboratory showed a high degree of hyperplasia and cell overgrowth. That hibernation had nothing to do with these changes is indicated b}' the fact that no change of this sort was apparent in animals taken in midwinter and examined immediately, and that in an animal examined on June first there were but slight evidences of involution of the hyperplastic gland.

The thyroid gland of the opossum consists of two ovoidal lobes situated one on either side of the trachea at the posterior end of the larynx. Usually no isthmus is present but remains of it are seen in the form of minute lobes attached to the posterior end of the main lobe. In some cases this isthmus lobe reaches a considerable size, and in one case a complete isthmus was found. In one case also an accessory thyroid gland was found in a mesial position low down in the neck.

Figure 1 represents a section from a thyroid gland of an animal sacrificed immediateh' after its arrival at the laboratory. The vesicles in many were larger than in the illustration, the amount of colloid greater and the epithelium flatter. It will be noted that this gland differs from the familiar type of vertebrate thyroid in two features, namely, the presence of a second sort of cell and the presence of large crj'stalloids in the regular epithelial cells.

^riie crystals are invarialjly present in the cells of the thyroid gland examined immediately after capture of the animal, though as will ai)pear later they may be absent or nearly so in the glands during the period of active hyperplasia. They are exclusively intracellular in the epithelium of the vesicles, and never occur in the parietally placed ovoidal cells. Their solubilities have not been accurately determined. Their prf)toin nature is indicated by

THYROID GLAND OF THE OPOSSUM

433

Figure 1

the strong Millon's and xanthoproteic reaction^; which the>- give in sections. They are visible in the fresh tissue examined in salt solution, but disappear with crossed Xicols. ^^^len the animal is injected with an oxazime dye known conmiercially as "new methylene blue GO," the crystals stain a deep Ulac color. The cholesterin reaction, and the reaction for phosphates are negative. The staining with new methylene blue GG in the fresh gland indicates their permeability to this dye. and suggests that notwithstanding their crystalline form they are permeable to oth(M" substances in solution.

The ovoid cells resemble anterior lobe cells of the hypophysis. Thoy contain a multitude of tiny granules, easily visible in the fresh cell, though of low refractive index, and staining readily in the living cell with the dye mentioned in the foregoing paragraph. The nucleus is large, oval in outline, located nearer one end of the cell, and richer in chromatin than the nuclei of the regular thyroid

434 H- H. BENSLEY

epitliolium. In stained preparations, among the granules in the pole of the cell which contains the larger amount of protoplasm, may be seen the tlelicate network of canals which Holmgren regards as of trophospongial origin but which I consider the homologue of the vacuolar system of plant cells. In these canals is a substance which stains faintly pink in sections of formalin Zenker material stained in ]Mallory's phosphotungstic acid hematoxylin. Sometimes these canals are expanded locally to oval, fusifomn, or spherical vacuoles containing the same substance.

These cells are always peripheral in position, and never extend to the lumen of the follicle. They are, however, in immediate contact with the follicular epithelium, and no reticulum extends between the two type of cells. They are distinguished from tissue mast-cells by the fact that the granules of the latter stain pink intra vitam with new methylene blue GG, while those of the ovoid cells stain blue. From Unna's plasma cells and from fibroblastic cells they are distinguished by the discreteness of their granulations, l)y their size and by the fixation properties. The best mode of demonstrating them is fixation in formalin zenker, staining in IMallory's phos])hotungstic hematoxylin, in which the granules stain deeply blue. In preparations stained with hematoxjdin and eosin the granules stain red, and a similar distribution of the acid and basic dyes follows stainhig with toluidin blue and acid fuchsin. In the preparations so stained, blue stained floccules may be seen distributed through the cell protoplasm, in additif)n to the small oxyphile granules.

The distriliution of the ovoid cells in the thyroid of the opossum is irregular. In three glands serially sectioned they were more abundant in the anterior three-fourths of the gland. The posterior fourth contained few and the isthmus and one accessory thyroid none. That the cells in question are special internal secreting cells there can be little doubt but what their homologiies in other vertebrates may be, remains wholly obscure. The possibility that they may represent a dispersed parathyroid has been considered but no proof of this has been obtained. Indeed they resemble the usual cells of the parathyroid glands as little as they do those of the thyroid though some resemblance to the eosin

THYROID GLAND OF THE OPOSSUM 435

ophile cells described in the human thyroid by Welsh and others may be perceived.

As indicated above, the thyroids of all animals examined after two or more weeks in the laboratory show a high degree of hyperplasia and cell overgrowth. In the first month of this process numerous mitoses may be seen in the cells of the th>Toid gland, and the latter increase considerably in size. This increase in size is associated with a proportional increase in the quantity of mitochondria and with an increase in size of the individual filaments. Though the process is invariable in the animals kept in captivity there is some variation in the rate at which it proceeds.

Figure 2 represents a follicle from a gland taken from an animal kept in the laboratory for a period of six months. The hj^perplasia though high is not materially greater than that observed in two animals from the same group killed during the first month of captivity. Indeed, the results of the obserxations on all the groups indicate that the hyperplasia proceeds very rapidly at first, then slows down, though mitoses may be found even after six months even in glands which are reverting to normal type after iodine administration. It will be noted in figure 2 that the follicle has expanded to a large complex mass of cells in which the original lumen is still visible though it no longer constitutes a secretion space. Instead, secondar}' secretion spaces, suggesting an attempt to reconstruct the thyroid by breaking the hyperjilastic cell-mass into new independent alveoli, are to be seen. These secondary secretion spaces, not much larger than a red blood corpuscle, contain a small gl()l)ule of colloid, wliich stains blue in Jones' modification of ^Nlallory's anilin blue method. The i)orders of the cells next the lumen contain a few granules, apjiarently a secretion antecedent. These granules differ from intracellular colloid in their properties inasmuch as they occur always at the extreme border of the cell while the colloid may be deep in the protoplasm of the cells or even external to the nuchnis itig. 3). They are with diliiculty preserved and then only in the most peripheral part of the piece of tissue, indicil iiig a different solubility from that of the intracellular colloid, ^\'hen fixed by formalin Zenker or by acetic osmic bichromat(^ thev stnin readilv with neutnil gentian and are

436

H. J{. HKNSLKV

1^ ^ P^

Figure

stained blue by Mallory's phospliotuiigstic hainatoxylin. They resemble certain granules which I have found in the hyperplastic thyroid of man but the granules are smaller than in man. Whether these granules represent an incompletely elaborated colloid, or another normal secretion which is exaggerated in the hyperplastic gland or a new secretion, I cannot fully determine. The facts so far, however, are opposed to the first assumption for as will appear later, in the gland which is reverting to normal as the result of iodine administration, and in which colloid secretion is proceeding

K

THYROID GLAXD OF THE OPOSSUM 437

at a rapid rate, the latter makes its appearance in the cells in the form of droplets which have unquestionably the characters of the colloid as seen inside the follicle, and this resumption of normal activity is associated with a disappearance of the granules described above. I am inclined therefore to the view that the granules represent a new secretory product or a nonnal secretorj* product different from thyreoglobulin, which is not present in the normally secreting gland in sufficient quantities for microscopic detection. In either event the secretory condition of the h\'perplastic gland would represent a perverted secretion indicated either by the introduction of new secretory products or the disturbed equilibrium of normal products. In these hyperplastic glands, here and there, but very rarely, small droplets of colloid may be seen in the protoplasm of the cells. They are usually more deeply placed in the cell than the granules discussed above and show the characteristic staining pro])erties of intrafollicular colloid.

The ovoid cells apparently share in the hyperplasia for in the hyperplastic glands they are much more numerous than in the normal glands. In some cases large groups of cells differing in some respects from both types, but which I take to be the result of hyperplasia of the ovoid ty^^e, are found. These cells stain deeply blue in ^lallorj-'s phosphotungstic acid hematoxyhn but the proplasm is much reduced in comparison with the normal oval cells, and the definite granulation is not seen. In these groups also mitoses may be seen.

The degree and rate of hyperplasia is subject, in different animals, to some variation, but some degree of hj-perplasia is invariable in the animals kept in captivity. In some animals the degree of hyperplasia is such that the whole thyroid gland is converted into a continuous complex of branching and anastomosing epithelial cords, which giv(> it a superficial re.«;emblance to the parathyroid gland.

In the intermediate stages of this hyi>erplasia some glands show a complete absence of colloid, most of them show a great reduction of colloid and. in the earlier phases, few of the border granules descrilied above. Tlir crystals also disappear or beconie greatly

43S

K. H. BENSLEY

Figure 3

redurod in size and in niiml)or. Since colloid originally present in large amount rapidh' disappears from the gland and since the evidences of normal colloid production are almost wholly lacking Tnote the absence of intracellular colloid as well as intrafoUicular colloid) and since the resumption of activity after the administration of iodine is marked by the ap]iearance of colloid both in the cells and in the follicles, in my opinion the conclusion, which is also probal)le on general biological grounds, that this gland in the phase of acti\e hyperplasia and cell ()\ergrowth has a low secretory rate and potential, is justified. On the other hand, after the period of most active hyperplasia is past the gland resumes activity though of an abnormal sort, marked by a low rate of colloid i^roduction and of crystal i)roduction and the appearance of a new secretory antecedent in the cells.

Since I wished to establish the independence of the hyperi)lasia of captivity with reference to the phenomena of hibernation the

THYROID GLAND OF THE OPOSSUM 439

number of animals available for experiment has been small. I hope to return to this aspect of the question next year for the readiness with which this animal's thyroid undergoes overgrowth in captivity suggests the possibility of controlling both hji^erplasia and reversion experimentally. The experiments on feeding gave no definite results though the border granules were more abundant in an animal kept for two months on meat and egg diet exclusively, as compared with several animals kept for a similar length of time on a mixed diet of meat, bread, and apples.

With regard to the effect of iodine administration one experiment made in the autumn suggests the possibility that there is a refractory period, in regard to iodine, at the height of hjT^erplastic activity. This animal, a female received October 21, was made the subject of a hemilobectomy on November 18. The gland removed showed a high degree of h^-perplasia. For two weeks the animal received a dose of 5 drops of s>Tup of iodide of iron daily, and, at the end of the time, the other lobe was removed and examined. No substantial change was noted in the second lobe.

On the contrary, experiments made in the spring on animals which had been present in the laboratory all winter and in which as the controls showed there was still a high degree of hyperplasia and but little tendency to reversion gave a prompt and characteristic reaction to iodine. On ^lay 8 four animals which remained in my collection were set aside for iodine experiments. Of these two were retained for control and to each of the others was administered daily 5 drops of syrup of iodide of iron. One of the controls died and was iuiavailal)le for examination. One of the iodide animals was killed after 17 days, the other after 24 daj's. The remaining control animal was thyrodectomised on the same day as the last iodine animal and the thyroids hxod for histological examination.

Both of the animals which received iodide showed an advanced degree of colloid involution of the thyroid gland, and this was more advanced in tlio twenty-four-day annual than in the seventeen-day one. In lioth practically every cell in the thyroid gland contained one or more droplets of colloid, and in each the re-formation of t)i(^ follicles had advanced to a degree which was pnv

THE ANATOMICAL KKCOHll. VOL. S. NO. 1>

440 li. K. BENSLEY

portioiial to the duration of tlic experiment. The control gland differed in no respect from the hyperplastic glands examined earlier in the j^ear, that is, showed practically no reversion. Figure 3 shows a section of the thjToid from the twenty-fourdays iodide animal. In this gland it is to be noted that there was no increase in the number of intercellular crystals as compared with the control gland. The resumption of colloid activity was a common i)roperty of the thyroid epithelimn and was not associated with the formation of the so-called colloid cells of Langendorff. The border granules disappeared from the cells with the resumption of colloid activity.

These observations on the opossum establish in my opinion by studj' of both th^ hyperplasia and involution the high degree of labilit}' and rapidity of reaction in the thyroid gland, on which ^larine and his co-workers have long insisted. They furnish an opportunity to control and to analyze the factors involved in thyroid hyperplasia. They confirm Marine's conclusion of a low rate of colloid production in the hyperplastic gland. In addition, by demonstrating a new tj^De of cell in the thyroid gland of the opossum and a new secretory product in the cells, they furnish objective evidence of that polyvalenc}' of thyroid secretion which has been so often postulated in the discussion of morbid conditions of the gland.

COVERS FOR DISSECTING TABLES

T. WIXGATE TODD From the Analominal La')oralory of Western Reserve University, Cleveland, Ohio

THREE FIGURES

In order that the border-line areas between the different 'parts' of a cadaver may be studied efficiently by the student, it is essential that dissection of the whole subject be carried out before dismembennent. In this way alone is it possible to obtain a correct impression of the vagus system, of the relations and distril)ution of the limb plexuses, of such muscles as the psoas and the obturators and of many other points in human anatomy. But the greatest technical difficulty in attempting this lies in the fact that the cadavers drv out so easily in spite of every care. For the student to be able to revise his work from time to time, it is essential that the cadaver be kept hi the best possible condition for six months or even more, during which time, of course, dissection is proceeding ever}- day. The utmost care leaves much to be desired in this respect because it is impossible, even were it desirable, to move the cadaver into a tank or store each day when dissection is finished, and no subject kept continuously on the dissecting-room table can long remahi in fresh condition even with the precautionary- measures of plenty of cloths and waterjiroof covers in addition to repeated moistening with the various fluids in vogue for such a i)uri">ose.

Our final attempt at Western Pu'ser\-e University to overcome the difhculty of adecjuately preser\-ing cadavera in the di.<;secting-room has met with such success that it may perhaps be a useful suggestion to other laboratories where the same difficulties are to he met.

Each table is mounted on castors so that it may be easily moved, and is jirovided with a galvanized iron cover, which can be dra\\ni to the ceiling when work is in j)rogre.ss. The cover is made of numl^er 20 galvanized siieet iron. Its dimensions are: length. 5 feet 10 niches:' breadth. 23 inches; depth. 14 inches. It is made watertight. Its lower margin is flanged round a steel wire to give it greater rigidity and finish. Its top is strengthened by three strips of iron i inch in tiiickness and 1\ inches in breacHh. These are riveted to the top, as showni in figures 1 to 3, and at eacii intersection an iron ring (2 inches in diam 1 The length had to be o feet, 10 inches, to fit our tables. A 6-foot length is desirable, but we find that with our routine measure of keeping the feet at right angles to the legs when the cadavera are embalmed, there is no difficulty in getting the cover to fit over all ordinary subjects.

441

442

T. W INC ATE TODD

3C

n

^

^

N

A B

c

I T!

' «L> .

m

■ 3.i'

Figs. 1 to 3 Plans for the making of the covers; scale one-half inch to one foot. Figure 1 represents the plan of the roof of the cover; figures 2 and 3 correspond to side and end elevations respectively.

eter) is bolted to the cover. The cover fits accurately on to the table, and can easily be raised or lowered at will ]\v means of cords antl pulleys fixed to the ceiling. Parallel with the suspension jiuUeys, but about 3 feet distant from them, two lOO-candle-power Mazda lamps are suspended, so that when the cover has been raised the table can be dra^^^l from a position directly under the cover to one beneath the electric lights. At first it was thought that when the cover was raised any contained condensed moisture might drip from the inside, but it has been found that there is not moisture enough to cause any trouble. The covers are j^ainted white both within and without, and thus add to the clean and tidy ajipearance of the room, while they do not interfere with the lighting when they are raised.

In addition to the efficient preservation of the cadavera, the covers keep the tables free from dust and therefore prevent any soiling of dissections placed on the tables. Moreover, they add to the neatness and well-being of the dissecting-room, and transform it, so far as the members of other departinents of the University are concerned, from a gruesome, somewliat rejiulsive apartment into a clean and pleasing lai)()r;itory. ('ort.ainly tlie appearance of covered tables is much more agreeable than that of tables on which the outlines of the cadavera are plainly suggested under the folds of the dark-colored waterproof covering.

COVERS FOR DISSECTING TABLES 443

The practical application of the idea was carried out by Prosector Leonhart, and the students were ciuick to recognize the advantages of the covers so that no 'regulations' are necessary for their use.

One last consideration may be mentioned in favor of such covers as are herein described. Should they become obsolete for their present purpose, their size, their watertight build and their strengthened top allow them to be turned upside down and used as tanks for the preservation of material. In case of such use the removal of the iron rings leaves the tank with two holes in the bottom into which can be fitted ordinary corks, and which provide for drainage of fluid and efficient cleaning.

A TANK von THE PRESEHN ATIOX OF ANATOMICAL

MATERIAL

r. WINGATE TODD From the Atinfotnicnl LnhoniU.ri/ of Western fiexerre Univerxity, Cleveland, Ohio

THKEE FIGURES

TIk' a(U'(iuate i^rpsen'iition of gross anatomical material requires some form of rccc^ptacle or tank, and if large (juantities of material or dissections eitlier of human or mammalian anatomy are to be carefully kept in good condition, it is necessary that the recej^tacles he so cheap as to he readily multiplied with the growing needs of the dejiartmiMit. In Western Heser\'e University we have, besides the dissecting-room, a museum, material for which accumulates faster than it can be mounted for exhibition, under present circumstances. In addition, arrangements with the various hospitals and with the city administration result in the ac(iuisition of nuich fetal material and the bodies of all animals from tiie Zoological (iardens. For these reasons it has been necessary to provide such accommodations as shall be at once cheaj) and ser\^iceable.

The form of tank descrilx'd below has fulfilled these recjuirements, and is therefore now being used in other laboratories. Hence it seemed advisable to make a record of it as one more laboratory furnishing .suitable for anatomical departments.

The tank, the plans for the manufacture of wiuch are also submitted with this connnunication, is made of galvanized iron, numlxM- 20 thickness. It is watcrtigiit, and ))rovided with a flange running round its upper margiii, tlie flange being \\ inches broad. The lid is sim|)ly a sheet of the same metal sligjitly scored diagonally from comer to comer so that a somewhat concave surface is i)resented to the contents and the flow of the condensed fluid which accumulates on the under surface of the lid directed to the comers. In order to seal the tank hermetically, the flange is thickly smeared with vaseline.

The thickness of the iron is found to be sufficient to prevent undue bending of the fUmge, but of course the n\sult of any accident to tlaiige or lid can readily be re|>aired witli tjie iiammer. The vaseline method of sealing has proved eciually efficient with the metliod wiierebv the lid is made to fit into a channel filled with glycerine round tiie top side.= of the tank, and is much more convenient than any other .scheme of tank lid. The inner surfaces of tank and lid are coated with asphaltum, which is renewed from time to time. The tank is cheap, tight, portable, does not get out of order, and is ver>' easily opened, closed or cleaned.

444

TANK FOR ANATOMICAL MATERIAL

445

i 1

3

Figs. 1 to 3. Plan of tank measuring 48 X 11 X 1-1 inches; scale one-half inch to one foot. Figure 1 shows the plan of the tank, with the lid in dotted lines. Figures 2 and 3 represent side and end elevations.

It has proved much easier to use and more convenient than the usual form of tank made of slate, stoneware, wood or lead-hned wood. It can always l)e made locall}', and the stock can be increased at verAshort notice. It can he made of any size iiji to one which will hold the larger Mammalia. But it is well to have a jihio; in the floor of the bigger tanks so that they may be emptied of fluid and cleaned more readily. The idea originated in a somewhat similar tank in use for the preparation of color specimens by the Kaiserling method in the Pathological Laboratories of the University of Manchester.

It is convenient for storing purjioses to have .-standard sizes, and the dimensions which have been found most useful by Mr. Leonhart, Prosector to the Department, arc the following:

Kaiserling prci)ar!itiun

Brain storage

Limbs or pelves

Torsos

DIMENSIONS I.V INCHES

I.oncth

Depth

•J 4

11

s

4S

U

s

4S

11

14

Is

•V)

14

446 T, \vix(;ate todd

It is obvious that any size may l)e made; only those which are most generally useful have been detailed. If it is desired to suspend the brains in fiuitl from rods i)laced across the tank, plaster slabs 1 inch in thickness may be made to fit the length of the tank. Grooves may then be gouged out of the upper margin to accommodate the rods. Finally, the plaster slabs may l)e rendered hard by lioiling them in oil. one of the l^rain tanks being used temporarily Un tliis purpose.

A SIMPLE ELECTRICAL HEATING DEVICE FOR INCUBATORS, ETC.

A. O. WEESE Deparlmenl of Biology, The University of New Mexico

FOUR FIGURES

The advantages of electricity as a means of heating incubators, paraffine baths, etc., are, I believe, everywhere recognized. Gas, \\ith all its uncertainty and inconvenience, is still employed in man}' laboratories on account of the prohibitive cost of the various high-priced electric incubators on the market. Many excellent devices have been designed by laboraton,' workers, and described in this and other journals, for the utilization of electricity for heating incubators originally designed for gas, and the most of these work \er\ satisfactorily where direct current is available in the laboratory-. The fact that there may be other laboratories confronted with the same problems that we have here has prompted me to offer the suggestions contained in this paper. Our laboratories are at present supplied with 110 volt alternating current only, and a lack of mechanical facilities suggested the modification of the old forms of gas regulators for use with electricity.

The heating element made use of was made of nichrome wire. About 40 feet of number 18 nichrome wire was wound, on a lathe, into coils of 5-inch inside diameter, and the entire coil .stretched between pegs arranged in a 'transite' base the size of the incubator. A wooden frame, lined also with transite board, was constructed so as to support the incubator about } inch above the coils. The heating chamber thus formed was completely insulated on all sides with transite. Copper leads connected the ends of the heating coils with ])inding posts on the outside.

For thermo-regulators I have ]>een able to modify several forms of gas regulators so as to operate a "make and break" device. Two examples will suffice. The mercur>--gla.- rises to the point (/) a cont-act is made, and when the mercur>' falls, due to cooling, the cont^'ict is broken.

The Roux bimetallic regulator may be utilized as follows: The hole at {x, fig. 2) should be reamed out and the upper part (c. d, c), insulated from the arm (//) by means of washers of mica or other non-conducting

447

448

A. O. WEESE

1

liij. 1 A modified Reiclicrt regulator; d, platinum terminal sealed into inside tube; d, terminal fastened to regulating screw;/, point of contact between platinum terminal and mercury.

Fig. 2' A modified Roux regulator; a, regulating screw; b, lock nut with terminal attached; e, terminal soldered to gas tube; .r, insulate! joiiif ; //, rcmilntor arm; z, point f)f contact.

inatorial. Wires are then attached at (b) and (c), tlic circuit Ix'ing mado and broken at (z). In this case the circuit is made when the himetaUic part, of the regulator is cooled below the desired teni})erature. Therefore, with this regulator, the connections siiould be arranged so that the current will flow through the heating clement when tlie cir

' Those figures have been reproduceil by courtesy of liausch and Lomb Optical Co.

HEA'I'IN'G DEVICE FOR INCUBATORS

449

cuit through the regulator is closed. When the mercury-glass form is used the opposite should be the case. Many of the other forms of gas regulator may be modified in a similar manner, at a ver>' small cost and with very little work.

These devices may be used with either direct or alternating current, but the arrangement will be somewhat different in the two cases. With either type of current the actual making and breaking of the heating current is accomplished by means of an ordinary telegraphic relay, to prevent arcing at the jjoints of contact in the regulators, through which only a very small current can be allowed to pass. \\'hen direct current is used, the regulator and electromagnet of the rela}' together with a large resistance {R) are connected in parallel with the heating element (fig. 3). The resistance is very large so as to allow just enough current to pass through the regulator to actuate the relay, and no more.

Fig. 3 Diagram of connections for direct current; .V, lu'ating elcineni ; L, electric line; t, regulator; r, relay; R, resistance.

Fig. 4 Diagram of connections for alternating current; B, battery; otherwise lettered the same as figure 3.

When alternating current is used, otlier means must i^e employed to operate the relay. In this case the manner of connecting is as shown in figure 4. To supply tlie regulating current hero 1 use a batter>- of three Columbia dry cells, with a "i.lO Ohm. tolograpiiic relay. As used here the cells require renewing about once in four months. Within that time there is absolutely no danger of tiie relay failing to operate, in fact in some cases the same i)atterv lias been used for a much longer time. With any of the devices mentioned temperature regulation is much more accurate than woukl be supposed. The variations, on a scale extending from room tcmiierature to a pohit 70'^(\ above room temperature, is always less than one degree, which is accurate enougii for all routine zo logical work, and nnich more accurate than tlie ordhiary gas regulator, t'sjiecially if the gas pressure is somewhat variable.

NOTICE

The next annual meeting; of the American Association of Anatomists "vvill be held in St. LouLs during December. The Association goes to St. Louis as the guest of "Washington University. The exact dates of the scientific sessions will be announced later.

w.'^

THE DEVELOPMENT OF THE ADRENAL GLANDS

OF BIRDS

VICTOR J. HAYS From Ihe Laboratories of Animal Biology of the Stale University of Iowa

EIGHT FIGURES

COXTIONTS

Introduction -lol

Observations -45^

Early development of cortical substance 456

Early development of chromaffin substance 461

Development after 216 hours 464

Development of the venous system 46.5

Development of the arterial system 460

The glands of the adult bird 471

Summary 472

Biblio>£rai)liy 473

IN'IKODUCTION

Although the development of the adrenal glands has been studied for the various classes of vertebrates for a number of years ajid by manj- investigators of recognized ability, there seems to be no very general agi'eement in their conclusions; aiul several o])]iosing theories have been develojiod as a result. This is especially true of the observations on the develojiment of tlu^ adrenals of birds. Here the field is in a most chaotic condition and a review of the literature shows, tliat while one theory may have th(> weight of evidence in its favor, eacli of them is supported by a number of investigators whose ability is of the liighest order. No minute description of the development of the vascular system of the adrenal glands of birds has as yet appeared. The development of the vascular system of the adrenal glands of mammals has been reported; but this cannot be taken iis a

THK ANATOMICAL RKCOnil. VOI . S, NO. 10

OCTOIIKH, I',) 14

4o'J VICTOR J. HAYS

criterion for the dcvolopniont in l)ir(ls, since in birds there can l)e no sharp division of the glands into cortex and medulhi.

The object of this investigation is to determine the source and manner of development of the various systems of the adrenal glantls of birds, and to make clear the relationship existing l)et\veen these different systems in the birds.

It is safe to say that there is no longer any doubt as to the nature of the adrenal glands, since the fact is well established that in the higher vertebrates they represent the more or less c(implete union of the interrenals and suprarenals of the lower vertebrates. The adrenal glands of the higher vertebrates are then a pair of organs, each representing an interrenal and a f^uprarenal gland of the lower classes of vertebrates. In the adrenals of mammals, the cortical substance represents the interrenals, while the medullary substance corresponds to the suprarenal glands of the lower vertebrates. Since in the case of birds there is no true medulla, the term 'chromaffin substance' will be used in place of the term 'medullary substance.' -^

According to the different investigators, the cortical substance has been derived from several possi})le sources; the mesenchyme, the mesonephros, the germinal epithehum, the peritoneal epethelium, and the sympathetic ganglia.

(iottschau ('83) and ]\Iinot ('97) took the view that the cortical sul)stance develops from the mesenchyme, the former working with mammalian embryos and the latter with human embryos. Tiic theory of mesonephric origin was suj)p()rted by 8emon ('87) and ('. K. Hoffmann ('92), both working with the embryos of birds. \'on ]\Iihalcovics ('85) working with reptiles, and Janosik ('83. '90). Fusari ('93), and Loisel ('04), working with bird eml)rvos. found a very iiitimate relationship between the adrenals and the genital glands and took the view that the adrenals <l('\('l(»j) from the germinal epithelium, so far as the cortical substance is concerned. O. Schultze ('97), from his obvserations made on embryos of Vespertillio murinus, concluded that the cortical substance of the adrenal gland arises from the sympathetic ganglia. The following observers suppf)rt the theory that the cortical substance of the adrenal glands develops from the

ADRENAL GLANDS OF BIRDS 453

peritoneal epithelium. Valenti ('93) and Souli COS), working with bird embryos, and Kuntz C\2), working with embryos of Thalassochelys caretta. This view is also supported by Poll f'06). The above citations do not cover the entire field but are given onl}^ to show the various theories which have been proposed to account for the cortical substance of the adrenal glands. Several theories have also been proposed to account for the development of the chromafl^n substance of the glands. Here again there is a lack of agreement in the conclusions of the various investigators, as was the case, in the observations on the development of the cortical substance. Gottschau f'83) and ^linot ('97) derived the chromaffin substance from the mesenchyme, the former from observations made on mammalian embryos and the latter, from human embryos. \'on ^Nlihalcovics ('85), from obser\'ations made on reptilian embryos, came to the conclusion that the chromaffin substance of the glands is derived from the germinal epithelimn. This theorj' was upheld by Janosik ('83, '90) and Valenti ('89, '93), both working with embryos of birds. Leydig ('53) described the interrenals and suprarenals of fishes and came to the conclusion that the suprarenals are derived from the sympathetic nervous system. Balfour ('78) in his classical work on the elasmol)ranch fishes, shows conclusively that the suprarenals are derived from the sympathetic ganglia along the abdominal aorta. Since that time many investigations have verified these conclusions and it is hard to account for the fact that many of the earlier investigators refused to accept the results of the work of Leydig and Balfour. Among the later investigators to hold the theory- of sjinpathetic origin of the chromafl^n substance are: Fusari ('90, '93), H. Rabl ('91), Minervini ('04), and Loisel ('04). These investigators all worked witli bird embryos. Souli ( '03) and C. K. Hoffmann, i89. 92), working witii the embryos of birds and reptiles, came to the theory of symi)athetic origin. This theory was also sup})orted by the work of Poll ( Oti) in which he used the embryos of manmials, reptiles, and birds. Kuntz ('12), from observations made on the embryos of Thalassochelys caretta. concludes that the clu'omafiin sulistance develops from the analgen of the

4")4 VICTOR .1. HAYS

prevertcl)ral sympatliotic plexuses. The above citations, while they do not cover the entire field, serve to show the confusion which exists concerning the development of the adrenal glands. A complete bibliogi'aphy will be found in the work of Poll ('06).

There are two general theories to account for the origin of the cortical and chromaffin substances of the adrenal glands; the theory of homogeneous origin and that of heterogeneous origin. The su]iporters of the theory of homogeneous origin have in turn derived the adrenal glands from the sympathetic ner\'ous system, from the mesenchj^me, and from the germinal epithelium. There is the same lack of agreement among the supporters of the theory of heterogeneous origin. These investigators have in tui'n deri\'ed the glands from the mesonephros and the peripheral part of the sjiiipathetic nervous system, the germinal epithelium and the sjanpathetic nervous system, and from the peritoneal epithelium and the s\inpathetic nervous system. Poll, from extensive observations and from a thorough review of the literature, shows that the w^eight of evidence favors the theory that the cortical substance of the adrenal glands of all vertebrates is derived from the peritoneal epithelium and that the chromaffin substance develops from the cells which break away from the anlagen of the peripheral part of the sympathetic nervous system.

\'ery little work has been done on the development of the blood vessels of the adrenal glands. Flint ('00) has worked out the blood vessels of the adrenals of mammals and reports a very interesting condition existing in this class of animals, especially as regards the venous circulation. According to this investigator the venous system may be compared to a tree, the terminal twigs uniting to form larger branches and as a natural result of this process a large central vein is fonned. He found that in most cases this central vein opens into the postcava as a single vein. In the dog, however, the central veins of the posterior and anterior lobes of the gland do nf)t unite, but open into the postcava sei)arately. This descrij)tion refers only to the venou^ system of the medullary part of the gland. The venous system of the cf)rtical part of the gland is of no great importance, being

ADREXAL GLANDS OF BIRDS 455

composed of the terminal twigs of the medullary venous tree. The arteries of the gland, according to Flint, are derived from five sources: A. phrenica. A. phrenica accessorius, A. lumbalis, A. renalis, and the abdominal aorta. These arteries branch out on the capsule of the gland fonning a network of blood vessels over the entire gland. These branches finallj- enter the cortex at various points and break up into capillaries, the terminal branches penetrating the medulla for a .'^hort distance.

Miller ('03j, working on the development of the postcaval vein in birds, did not make any attempt to work out the development of the veins in the adrenal glands other than to detennine their origin. He concluded that the veins of the left adrenal develop from the subcardinal vein and probably tho.se of the right gland are of the same origin.

Minot ('00) distinguishes between capillaries and the venous blood vessels found in several organs of the vertebrates, among these being the adrenal gland. He finds these blood vessels differing from capillaries in size, shape, relation to other tissues, and in their method of development. According to this author, these blood vessels which he calls sinusoids are larger than capillaries and are irregular in section. The walls of sinusoids are composed of a single layer of endothelial cells resting upon the parench\^na of the organ, while a capillary always has a connective tissue wall upon which the endothelial layer rests. The manner of development also differs, the capillaries developing from a chain of vasofonnative cells which becomes hollowed out and connected with a vessel already fonned, while sinusoids develop by the outpushing of the endothelium of the wall of a l)re-existing blood vessel.

The vascular spaces observetl and described b>' Kuntz ('12) in the adrenals of Thala.s.^^ochyles caretta are undoul^tedly identical with the sinusoids of Minot. Flint ('GO) finds no sinusoids in the adrenals of mannnals and is of the opuiion that the investigators who have re])orted them used sections which were too thin to show the true structure of the walls of the blood vessels.

The following observations are based exclusively on embr>os and adult of the domestic fowl (Oallus domesticus). All speci

45() VICTOR J. HAYS

mens wore fixed Avitli cliroin-aceto-fonnaklcliydo and stained hy the iron lieniatoxylin method. Embryos were injected with india hik after the method of Knower ('08). The adults were uijected with a gelatin mass. Sections used for the study of the develojmient of the vascular system were cut to a thickness of 20 micra. All other sections were 10 micra thick.

It gives me great pleasure to express my indebtedness to Prof. F. A. Stromsten for many helpful suggestions durhig my investigation of this subject and also for readhig the manuscript. I take the greatest pleasure in acknowledging my indebtedness to Prof. G. L. Houser for suggesting the subject of this investigation and for many helpful suggestions during its progress.

OBSERVATIONS

The early development of the cortical substance

The cells which are later to form the cortical substance of the adrenal glands of birds are first seen in the 96th hour of incubation. They ajipear as a thickening of the peritoneal epithelium, ventral and mesial to the mesonephros, ventral to the al)dominal aorta, and dorsal to the hind gut which is o]:)en at this time (fig. 1, ad.). The developing cells push in dorsally from the epithelium upon which they rest and become larger and more nearly circular in outline than those cells from which they arose, that is, the cells of the peritoneal epithelium. The nuclei are corrcs])()ndingly enlarged and mitotic figures may be seen in nearly all of them. The nuclei also differ from those of the parent cells in their staining properties, these nuclei all being less deeply stained and less granular than those of the peritoneal epithelium. It is probably due to the fact that the anlagen of the cortical substance appear so early in the development of the chick, that earlier investigators, using embryos which had passed this stage of development, derived the cortical substance from other sources.

During this early period of incubation the development of the cortical substance goes on with astonishing rapidity, and nine hours later, during the 105th hour of incubation, the cortical

ADRENAL GLANDS OF BIRDS

457

cells have piled up on the peritoneal epithelium so that a solid body is formed on each side of the base of the mesentery. In the meantime, folds have appeared in the peritoneal epithelium which throw these cell groups further from the base of the mesentei-y.

.^

<fY^' \ ^

I?

O.

^

Fifl. 1 TransvcM-sc section through the adrenal region of a 90-hour chick vmbryo; ad., anlagcn of the cortical substance; no , aorta. X 130.

Fig. 2 Transverse section through the adrenal region of a lOo-hour chick embryo; ad., anlagcn of the cortical substance; ao., aorta; sij., anlagen of the prevertebral sympathetic plexuses; v. sc, subcardinal vein. X 130.

laterally. At this jicriod they lie just mesial to tlie ventral side of the mesonephros. This is possible because the mesonephros lies closer to the median line than in the preceding stage, due chiefly to the fact that it has been gi-owing rapidly during this period. The character of the cortical cells has not changed

loS \I('T()H .1. MAYS

during; tliis jK'riod. hut tluMr iiuji;i-a(i<)ii lias gone on rajjidly until a chain of cells can he traced from the gi'ouj) resting on the ])eritoneal ejiit helium, to a point just slightly dorsal to the ventral level o{ the aorta (fig. 2, ad.). These cells then lie hetween the aorta anil the mesonephros, in the mesench>nne. In this migration most of the cells ])ass laterally to the sul)cardhial veins hut this does not liold true for all of them, since a few of them take a j^ath median to these veins. The shape of these cells and their nuclei, together with their stainhig ])roperties, make them easily identified and the course of their migration can be followed without difficulty.

Duruig the next fifteen hours, or after 120 hours of incuhation, the cortical cells have hecome detached from the peritoneal e])ithelium and all of thorn have migrated dorsally. At this stage of development they appear as scattered cell groups reaching from the dorsal level of the suhcardinal veins to the middle level of the aorta. They have reached ahout the same level on hoth the right and left sides of the aorta, though those on the right side may he slightlj' in advance of those on the left. These cell groui)s are scattered through the mesenchyme hetween the mesonephros and the aorta and have practically invaded the entire region. The nuclei are still circular in section and show well developed mitotic figures. Occasionally cells may he seen undergoing division. Isolated cells are still circular in outHne hut tliose which are found in groups have become more or less flattened by contact with the other cells of the grou]) and ])resent an oval outline. They may still he idcntihed from anything which has yet appeared by their nuclei and staining proi)erties (fig. 3, ad.). The relative position of th(^ cortical cells at this jx'riod is shown by figure (5. It is seen that they lie on the dorsal side of the suhcai'dinal veins, lateral and ventral to the aorta, and uK'sial and ventral 1o llic i)ostcardinal veins. The region which they occupy extends ])()steriorly to a point about level with the anastomosis of the suhcardinal veins in the median line, ventral to the dorsal aorta.

From the 12()th 1o the 13()th hours of incubation there is a j^reat increase in tlx' mass of llx- cortical substance. This is

ADJ{K.\AL (;LA.\D.S of BIRDS

459

sy.

ch. a,

Kig. 3 TransviMse section through tho adrenal region of a IJO-hour i-hick rnibryo; ml., anhigen of the cortical substance; no., aorta; sy., anlagen of the prevertebral syni|>athetic plexuses; r. sc, subcardinal vein. X 90.

Kig. 4 Transverse section through the adrenal region of a 130-hour chick embryo; nd., anlagen of the cortical substance; oo.. aorta: ch. a., anlagen of th«> chromaffin substance; vies., mesonephros; ,<//., anlagen <if the prevertebral sympathetic i)lexuses: v. .sr., subcardinal vein. X 90.

4<)() \I(T()U J. HAYS

duo. j)artly to the fact that the cells are no longer scattered through tlie inesench}ine, but have collected in large groups, and jiartly to the fact that the number of these cells has been increased by the division of the older cells present in this region. At this stage the cells are arranged in large solid groups hing dorso-niesial to the subcardinal veins and ventral to the mesonephric arteries which run over the anterior ends of these cell groups. These cells then occujiy the region l)etween the aorta and the mesonephros in the region outlhied above. Owing to the close arrangement of the cells, they are losing their regular shape, but the nuclei remain circular in outline and continued development is shown by the presence of mitotic figures (fig. 4, ad.).

After 144 hours incubation the cells have become more closely grouped than in the preceding stages and are found in large oval masses on each side of the aorta. The nuclei have become more granular but still contain mitotic figures. The cells are becoming more in-egular in outline and, on account of the proximity of these cells to the mesonephros, and on account of the close resemblance between them at this time, it is difficult to distinguish one from the other. Such conditions, doubtless, are responsible for the conclusions of some of the earlier investigators that the cortical substance of the adrenals is derived from the mesonephros. Careful investigation reveals a thin layer of flattened mesenchyme cells between these two bodies.

Twenty-four hours later, during the 168th hour of inculcation, the mass of the cortical substance has greatly increased. The cells have arranged themselves m irregular chains and have taken a roughly hexagonal shape. The nuclei stain much darker than previously but they still show mitotic figures in great numl)ers, showing that the cortical substance of the gland is still hicreasing by division of its own cells. The mass of cortical substance is roughly circular in section at this time and occupies practically the .same level as the aorta and has about the same cross sectional area through the center. The mesonephros has developed ventrally until it is in contact with the adrenal only at its dorsomesial angle. The subcardinal veins still lie on the ventral

ADREXAL GLAXDS OF BIRDS 461

border of the glands. At this period of development, connective tissue fibers are collecting around the gland, giving promise of a connective tissue capsule later. A few of the fibers are seen within the body of the gland, between the cords of cells.

The cortical substance continues to grow rapidly during the next twenty-four hours and after 192 hours of incubation its cross sectional area is fully twice as great through the center as that of the aorta. The gland is about 2 mm. long at this period. The cell mass is becoming less dense than it has been for some time. A large number of the nuclei still show mitotic figures but in many of the cells these figures are no longer present. At this time, blood cells may be seen in the relatively large openings between the cords of cortical cells.

Little change in the form and size of the gland is seen durmg the next twenty-four hours. The greatest changes are seen in the internal arrangement of the cells. The gland has become much more vascular during this period and many more spaces have appeared between the cords. The cell cords have become very dense and compact, making it difficult to see the outline of the individual cell.

The above observations lead to but one conclusion, namely, that the anlagen of the cortical substance of the adrenal glands arise as groups of cells which proliferate from the peritoneal epithelium.

Early development of the chromaffin substance

The observations on the development of the adrenal gland show that the anlagen of the cortical substance arise from the peritoneal epithelium. Observations on the origin of the chromailin substance seem to show that it arises, not from the same source as the cortical substance, but from the anlagen of the prevertebral sympathetic jilexuses. It is evident then that the adrenal glands arise from two so})arate genu layers, namely, the mesodenn and the ectodenu.

After 120 hours of incubation, large oval cells are seen migrating ventrally from the sMupathetic trunks on each side of the aorta. These cells migrate shigly in most cases and most of

4()2 \I<T()H J. HAYS

them pass around to tlio ventral siile of tlie aorta and later fonn the prevertebral sj'inpathetic ])lexuses (fig. 3, sy.). At this stage of development the anlagen of the cortical substance are a loose group of cells on each side of the aorta. The cells of sympathetic origin migrate in a jiath which causes them to j^ass between the aorta and the groups of cortical cells. At this time there is no connection between these two kinds of cells. The two kinds of cells, cortical and sjmjiathetic, are easily distinguished from one another by their size and affinity for stains, the latter being the larger and taking the deeper stain.

The first evidence of any connection between the anlagen of the prevertebral s\inpathetic plexuses and the chromaffin substance is seen after 180 hours of incubation. The cortical cells have arranged themselves in large, compact masses by this time and have taken a definite outline. At this time, some of the cells migi-ating from the sjTnpathetic trunks turn off ventrally in the region of the adrenals and either enter them, or become attached to the surface of the cell groups. Figure 4 (sy.) shows several of these cells on the inner edges of the groups of cortical cells, and on the right, one cell may be seen which has penetrated to the center of the cortical substance. This development continues for some time and these new elements, the cells of s>nnpathetic origin, do not seem to differ in any way from those which pass on to form the prevertebral s\inpathetic plexuses. These cells, then , are indifferent in nature. As the growth of the embryo goes on, more of these cells are found entering the cortical substance of the gland and collecting, in most cases, in groups of two or three. Single cells, however, are found scattered throughout the cortical substance. During this period they may be found almost anywliere within the cortical substance and a great many are found around the surface of tlie glands.

After 168 hours of incubation, the ('(>]ls which are to fonn the chromaffin part of the gland are l)eginning to show some difTercntiation. Those which liave entered the cortical substance are no longer large circular cells with round, clear nuclei. The shape is becoming irregidar, as a general rule, and the cells are smaller than originjilly. The inirlei are oval and have become quite

ADRENAL GLANDS OF BIRDS 4()3

granular, in many cases, even more so than those of the cortical cells. They are most easily distinguished from the latter cells by means of their staining properties, both nucleus and cytoplasm takhig a deeper blue color with the iron hematoxylin method. These invading cells, at this stage of development, show a tendency to arrange themselves in cords throughout the cortical substance, though many solitary cells are also found. This seems to be the height of the migration of the cells from the sympathetic trunks and at this time the mesenchyme around the glands is shot full of them, and they can be seen entering the glands from all sides.

During the next twenty-four hours, the chromaffin cells within the glands have increased greatly in number and most of the sympathetic cells have disappeared from the mesench>Tne around the glands. At this time the chromaffin cells are arranged in cords, many of which have pushed in close to the venous blood vessels. This location with regard to the venous circulation cannot be taken as a general rule at this period of development, since a great number of these cords do not seem to bear any relation to the blood vessels.

The arrangement of the chromaffin cells undergoes a marked change during the next twenty-four hours, 216 hours' incubation. The cells were first found scattered, either singly, or in small groups, throughout the cortical substance. Later they became arranged in cords or columns. At this period the cells cords break down, but do not return to the original condition of solitary cells scattered throughout the cortical substance. Instead of this scattered arrangement, the cells are found in small groups arranged around the venous blood vessels. Of course, not all of th(^ grcnips are so situated, since the cords from which they originated were not all in contact with the blood vessels.

These observations bear out th(> contention that the chromaffin substance of tlie glands does not arise from the mesench^nne or germinal ei)itheliuni. Init from the anlagen of the prevertebral synijKithetic plexuses. These cells enter the cortical sui^stance as indifferent cells and later become differentiated to form the chromaffin substance^ of tlie glands.

MA

\I(T()H ,1. MAYS

Development after 210 hours' ineufyntinn

Aftor 21() lioiirs' incuhation the charactoristic features of tlie adrenal glands are firmly establislied and the development of tlie glands from that thne up to hatching is chiefly one of growth so far as the cortical and chromaffin cells are concerned. The glands increas(> in volmne slowly and become more vascular until, at the end of the period of incubation, they have the

■^^■j^\

^ ^..^^.^^^^ /•■

' 5> '

/ / 4»- ■ . •■ «J* .' ■ 0- ft , ® «■

-^ ' ' CO- SI. <*

ch.

I- in. o 'rransvcrsf section llirniigh tho adrenal ^land of a 2f)4-liour chick rnibryo; no., aorta; r//.. chromaffin substance; co., cortical substance; .s/.. sinusoids; .v//., anlatfeii of tlic j)revcrtebral synijiathctic plexuses. X 90.

appearance, in section, of a large numl)er of groups of cells almost surromided l)y blood vessels.

An idea of tlie struetinv of the gland may be had by referring to figure 5. Here the gland is seen lying betw(M'n the kidney and the aorta, practically filling this region. The substance of the gland is cut up in-egularly by venous simisoids which form a network throughout the entire gland. The cortical cells are arranged in irregular cohnnns which pass around these blood vessels and seem to form \\w foundation for all oilier elements

ADRENAL GLANDS OF BIRDS 465

of the gland. The chromaffin cells have no regular arrangement, but are found in groups varying from two or three, up to thirty or forty cells each. The only regularity to be seen in the chromaffin groups is in their relation to the venous blood vessels. Except in exceptional cases, at least a part of each group is in direct contact wdth at least one of these blood vessels.

The connective tissue, which was first seen forming around the glands at the 168th hour of incubation, develops very slowly, but after about seventeen days of incubation a dense capsule has been formed around each gland. The connective tissue is confined almost entirely to the surface of the gland but in several places rather large masses of it may be seen entering the substance of the gland. This connective tissue breaks up at once and within the gland only very small fibers are found. These fibers are found only between the cords of cortical cells.

The development of the venous system

Owing to the structure of the adrenal glands of bii'ds, the development of the blood vessels cannot be taken up separately for the cortical and chromaffin parts, as has been done for mammals.

The blood vessels of the adrenal gland develop so slowly that for specimens taken twelve hours apart, very little difference can be seen. For this reason it is very difficult to determine at exactly what age they first appear. The process is a gradual one and each condition blends perfectly into those immediately preceding, and those immediately following it.

As early as the 120-hour stage of development a few scattered blood cells are found throughout the anlagen of the glands, but no more are found than are jiresent in the suiTounding mesenclnnue tissue. Xo direct connection with any blood vessels can be seen at this stage of development but in several ]ilaces the wall of the sulx'ardinal vein pushes out dorsally into the anlagen of the gland for a \ery short distance. Xo break or division of the wall of \\\v \(Mn cati br seen at this time. I-'iffiu'e (i shows the

400

\I(T()]{ .1. HAV.S

V. a. -■-'—

V. pc. ._

. pc.

V. sc ao. V. sc

V. pc

-V. pc.

I'ig. G Reconstruction of the vascular system in the adrenal region of a 120hour chick enibrj-o; dorsal aspect; ad., anlagen of the cortical substance; (m., aorta; r. a., adrenal vein; r .pc, post cardinal vein; r. .sc, subcardinal vein.

Fig. 7 Scnii-diagraniniatic drawing of the connection between the subcardinal an<l the postcardinal veins through the adrenal in a 168-hour chick embryo; ventral .aspect; adr., adren:d gland; v. pc, postcardinal vein; r. .sr., subcardinal vein.

relation of the subcardinal veins to tlie glands and in several

places tlic outpushinp; of the Ncins into llic glands may l)e seen.

Sections of the glands at tli(> l.'^O-liour staf2;e of development

sliow that tlio subcardinal veins have pushed further into the

ADRENAL GLANDS OF BIRDS 467

gland tissue than in the previous stage. No great modification of the gland can he seen and there is no apparent increase in the number of blood cells found in the gland. The evaginations of the subcardinal veins are very small at this time, but can be traced by the structure of their walls, which at this time are composed of only a single layer of endothelial cells. Their walls are of the same structure as those of the subcardinal veins at this period of development.

This development continues during the following fourteen hours so that at this period, 144 hours' incubation, these newly formed blood vessels have reached almost to the dorsal side of the gland. In several places, lateral branches are fomiing but these extend for only a very short distance. In no case was less than two of these venous trees found and in most cases three or four of them were present. This means that the venous blood vessels of the gland are formed, not bj^ the division of one larger vein, but from several which push in from the subcardinal veins.

The development of the venous system continues by the branching of the vessels present in the gland until, after 168 hours of incubation, the gland has the api:)earance in section of having many irregular pieces cut out of its interior. At this period of development a new venous connection a])iiears in the glands of birds (fig. 7). By the gi'owth of the glands they come to lie ventro-median to the ])ostcardinal veins. At this thne, these vems tm-n ventrally to form the renal jiortal system, and in the regic^n of the adrenals a In-anch is given off to the glands. Each postcardinal gives off a In'anch to the gland on its side of the body cavity. These veins push into the glands but instead of branching after the manner of the subcardinals and fonning a system within the glands, they open directly into the blood vessels already present in the glands. In other words, they oj>en into the venous tree already fonned from the subcardinal veins. This condition naturally leads to the conclusion that there is a portal system formed in the adrenal glands of birds which might be called the adrenal jKirtal system.

At this tinu> the aorta and the postcardinal and subcardinal veins show coniuM'tix c tissiu^ in their walls, ujion which the

TIIK AXATOMICM. HKCOHl>, VOL. S. NO. 10

468 VICTOR .1. HAYS

eiulotliolial lining rests. Tliis is not true of tlio vonous blood vessels in the glands. These show no connective tissue in their walls and are larger than any capillaries found at this time. Owing to the difTerence in size and structure of these vessels I shall not call them cajiillaries, but shall adopt the tenn 'sinusoids,' jH'oposed by ]\Iinot for this type of blood vessel.

The development of the sinusoids goes on steadily, but after 216 hoiu's of incubation there does not appear to have been any appreciable increase in their number. The most noticeable change in the appearance of the gland is in the great increase in the size of the shuisoids. This growth, however, has in no way affected the nature of their walls, and they are still made up of a single layer of endothelial cells (fig. 5, si.). The adrenal portal system has broken down at this time. It is a transitory condition, persisting through the eighth and iiinth daj^s of incubation only. It is significant that this connection with the post-cardinal vein should disappear as soon as the sinusoids have increased greatly in size. It should also be remembered that the greatest activity in the development of the chromaffin substance took place during the existence of this system.

Until after 240 hours of incubation, the sinusoids are found to open into the subcardinal veins in many places and by means of no very definite vessels. At this stage, 240 hours, the sinusoids seem to join into two groups near the posterior end of each gland and enter the subcardinal veins by means of four well defined veins, two for each gland. There is no evidence of a central vein running longitudinally through the gland, but this is to be expected since the sinusoids do not arise from the branching of a single xcin, l)ut from four or five veins which push in from the .sul)cardinal vein. Each one of these veins then forms a system of sinusoids b}' re])eated branching in the gland. This later development is then the combination of several of these systems at their bases to fonn a larger sj'stem. Since there are two veins found opening into the subcardinal vein, it follows tliat these numorous systems have combined to form two distinct systems of sinusoids in each gland. These systems are distinct only in ])oiiit of origin, since there arc numerous anasto

ADRENAL GLANDS OF BIRDS 469

inoses formed between the sinusoids of the different systems and between the sinusoids of the same system.

The later development of the venous system is in no way remarkable. The terminal sinusoids continue to branch slowly up to the end of the period of incubation. At this period the gland is filled with sinusoids, so much so that in section they appear to occupy nearly one-half of the entire volume of the gland.

There can be no doubt as to the origin of the venous system of the adrenal glands of birds. It develops from inpushings of the subcardinal veins and penetrates the glands by means of numerous branches which in almost ever\' case are directly in contact with the chromaffin substance.

The development of the arterial system

Observations on the development of the arteries of the adrenal glands reveal no conditions which are in any way out of the ordinary, and the condition is the same as that of any organ of this type.

The earliest connection found between the glands and any of the nearbj' arteries appears after 120 hours of incubation. At this time a small blood vessel is .seen passing into the cortical substance of each gland from the anterior pair of mesonephric arteries. At this ]Deriod the walls of these vessels are not very distinct, and within the gland no capillaries can be seen. For some time very little progress can be seen in the development of the arteries. After 144 hoiu's of incubation the only increase in the complexity of the arterial system is the apiiearance of a very few indistinct capillaries within the cortical substance.

During the next twenty-fom* hours the arterial system of the glands develops rapidlj' and several new vessels appear during this period. .Vn artery is given off by each of the anterior mesonephric arteries just before they enter the mesonephric glands. These arteri(»s run anteriorly, one along the lateral border of each adrenal gland and two l)ranches are given off to each gland by its respective arter>', one near the posterior

ui(l the other near the anterior end of the gland, and each sends

47n

VK TOU ,1. HAYS

hranchos into tlio cortical part of tlic {!;laii(l. Tliis docs not «)ccur, liowever, until after several l)ranclies ha\e been fonned on the surface of the gland antl instead of a large artery penetrating the gland, directly, it is broken up and the branches are very small Avhcn they enter the substance of the gland. Still another arterial connection a])i:)ears at this time. This is a small artery Avliicli runs directly from tlic aorta to the post<M-ior

ventral

Kiji. 8 A, The arteries of tlie adult fowl in llie region of the adrenal jilaiids: ventral aspect; adr., adrenal gland; au., aorta; n. r., renal artery. B, The veins of the adult fowl in the region of the adrenal gland; ventral aspect; adr., adrenal gland; v. n., adrenal vein; r.p., postrava. X 2.

end of the left gland. This artery also branches on the surface of the gland before entering the cortical substance. Within the glands all tliese arteries divide still further and the terminal branches are so small that in section they a]i]iear to be smaller than the blofxl cells. It is jirobable that in the li\ing gland these capillari(>s are somewhat larger than in the sections observed. None of the capillaries within the gland were foimd in the chromaffin substance but there can be no doubt that at least the tcriiiiiial braiiclics soiiict inics ])enetra1(' this ])avt of the gland.

ADRENAL GLANDS OP^ BIRDS 471

Here again, the greatest growth of the chromaffin substance is accompanied by a correspondingly- rapid development of the vascular system.

This practically completes the development of the arterial system of the glands. At a later period, about 192 hours, the connection between the mesonephric artery and the left adrenal disappears. This artery which disappears is not the one which arises from the branch of the mesonephric artery which runs anteriorly along the lateral edge of the gland. This artery runs directly from the mesonephric artery to the gland. The corresponding artery to the right gland remains (fig. 8). Aside from this modification there is no further change in the external arrangement of the arteries, ^^'ithin the glands there is a slight increase in the number of capillaries and the nature of their walls undergoes a marked change. When first formed, the walls of the capillaries contain no connective tissue, but as the period of incubation draws to a close, a small amount of it may be seen in the walls of the larger ones. If any connective tissue is present in the walls of the smaller branches, the amount is so small that it cannot be seen in sections prepared b}' iu\y of the ordinary methods.

The glands of the (idult bird

In the adult biiil, the adrenal glands lie just anterior to the l)ifurcation of the postcava, one on each side of the median Hue. They are about 1.5 cm. long and 0.5 cm. wide at the widest part. The right gland is roughh' triangular, while the left is oval in outline (fig. 8, ad.). The internal arrangement of the cortical and chromaffin substances shows no change from the condition found in the embryo at the close of the jieriod of incuiiation. In the natural increase in size of the glands it is the cortical substance, chiefly, which has increased in mass so that there is much more of this in proportion to the chromaffin substance than was jiresent in the embryo. The same relation between the blood vessels and the tis.^^ue of the gland is found here as was described in the well advanced embryos. The sinusoids jiass between the grcnips of chromaffin cells, while the capillaries lie in the cortical substance but each encroaches to a certain extent upon the territory of the other.

472 VICTOR .1. HAYS

The trunks of the venous trees have increased f2;reatly in size and form large central vessels which may be C()mi)ared to the central vein of the adrenal gland of maimnals. The sinusoidal character of the venous blood vessels persists in the adult and even in the largest vessels very little connective tissue is found in the walls. Near the close of the period of incubation, the venous blood was found entering the postcava by means of two sejxirate veins from each gland. This condition is not found in the adult. Tlie two veins anastomose on the ventral surface of the gland and the blood f