Book - A History of Embryology 1959-3

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Needham J. A History of Embryology. (1959) Cambridge University Press, London.

1959 Needham: Chapter 1 | Chapter 2 | Chapter 3 | Chapter 4

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This historic 1959 embryology textbook by Needham was designed as an overview of embryology history. Currently only the text has been made available online, figures will be added at a later date. My thanks to the Internet Archive for making the original scanned book available.
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Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

Chapter 3. Embryology in the Seventeenth Century

1. The Opening Years

A cool) deal has been written on the history of biology in the seven- teenth and eighteenth centuries by those who apply the distinction be- tween the “Baroque” and “Rococo” periods. Since the art-styles from which these names are derived had relatively little influence in England, it is natural for English writers and readers to experience some hesita- tion in accepting at any rate all their applications to the history of science. Sigerist's essay on the position of Harvey may form a suitable introduction to this point of view, and the treatise of Bilikiewicz divides all the embryology of these centuries quite sharply into Baroque and Rococo.

Doubtless there is something to be said for such a division. Thus Harvey is said to stand as the typical Baroque biologist, since his out- look was “dynarnie"; he studied the movement of the blood and the morphological movement in space-time of the developing embryo. With him embryology stepped from the confines of pure anatomy. Yet it seems to be overlooked that Hippocrates, Aristotle, Coiter and Aldro- vandus (to say nothing of the Cleopatra legend, ct’. p. 65) all employed the method of comparing morphological change against time in develop- ment.‘ Another characteristic of the Baroque period was its political absolutism, mirrored, it is suggested, in the absolutist claims for reason’s supremacy which provided the basis for the wilder assertions of pre- formationism. But also in the hands of men like Gassentfi, Descartes and Leibniz, this thorough-going nationalism gave rise to the a prion" mathematical attitude to biological phenomena, exemplified inDescartes' own contribution to embryology (p. r 5 5). Finally, it involved a prefer- ence for mechanistic as opposed to vitalistic interpretations, e.g. the Epicureanism of Highmore.

1 Cf. the interesting recent resume of H. Fischer. ' On the significance of the time—cone:pt for seventeenth-txntury biology the obscure but interesting essays of d'Irsny should be consulted. Page! has us I

ti:;l(y"£:w_lt'n,L.t)I.3. vun Hel.mont': meure De Tempou on hiologicnl time (part at \ rr5 A iiisroxw or mnnrocoor

711° R_°°°C° P€1'_i0fl. it is said, brought in new movements mm-.1, freedom 1!! the political sphere, and this took the (am, in sdcnoc oh

to empmdsrn, so that the hiological observations of Reditand 9 were as much oonnected with the romantic movement as the philosophical speculations of Rousseau. In the Encyclopaedists, the connection betwun empiricisrn in science and political freedom is particularly well seen. But when it is suggested that the new eminence of the female sex in the Rococo period, unimaginable to previous ages, was connected with the temporary triumph of ovisrn,‘ the mder my question whether the Spenglerian method is not being arr-ied too far.

1Ernilius Parisanus, a Venetian, now dealt with embryology in the fourth, fifth and sixth books of his De Subtilitare. They were entitled

as follows:

(4) Of the principles and first instruments of the soul and of innate heat, (5) Of -the material of the embryo and of its etiicicnt cause, (6) Of the part of the animal body which is first made, and of the mode and order of procreation.

Parisanus is very wordy, but he has the merit of giving many quotations from the lesser known authors, and providing (as a rule) accurate refer- ences. He held that the spleen was formed in all development before the heart. and that neither heart nor lungs moved in ultra. With regard to the controversy over the function of white and yolk, he was in agree- ment with Fabricius, but he firmly opposed the view that the chalazae were the first material of the chick, rather, it must he confessed, be- cause of the opinion of Aristotle than from personal conviction. Never- theless, his own observations were noteworthy, and he will always be remembered for his opinion that the heart of the chick begins to beat some time before any red blood appears in it.

Parisanus was the last of the macro—iconographic group of sixteenth- century embryologists. Their labours established the fundamental morphological facts about the developing embryo; the first step the history of embryology. But there were numerous errors in their work, and Harvey, who occupies a terminal or boundary position, was destined to correct them. He marks the transition from the static to the dynamic conception of embryology, from the study of the embryo as a

r fiajkigwiez, p. 73. "Die I-‘nu hnbe heute nieht nur dz: Rudy. dass -hm Scb°-‘I'M und \V' In Dithyrnrnben besurtgen wrrde: wenn ue dm, BN1 -uf den 'l'l:rone einnehmen coder hber 'ntIO11c vcrfugen konne, oder Wynn ue_ tm nllgemum gesellsetnftliehen Leben mi: der wnchrenden Glenehbereehtmmg Iggllu wortlu-Jxere Roller: tlbemehmen kbnne, S0 tube are such dn Recht. 11:,“ an 5' an der Ernbryologie dem mlnnhchen Gesehlcchtz in die _Augen zu Id’ uzg ‘hm \Vesen, dag dieselben Rechte nuf Fresher: habe. Der Ovlscnus hes: es: mawehen.“

changing succession of shapes, to the study of it as a causally governed organisation of an initial physical complexity, in a word, from Coiter and Fabricius to Descartes and Mayow. Iconography did not die: on the contrary, the improvement of the microscope gave it new life, and the micro-iconographic school emerged with its principal glory, Malpighi.

Harvey sums up the work of the macro-iconographic period in the historical introduction contained in Ex. No. xrv of his De Generations Animalfum.‘ I give it in full in the beautiful seventeenth-century English into which l-Iarvey‘s Latin was translated under his guidance by the physician Martin Llewellyn.

\Ve have already discovered the Formation, and Generation of the Ego; it remains that we now deliver our Observations, concerning the Procreation of the Chicken out of the Egge. An undertaking equally difficult, useful], and pleasant as the former. For Nature's Rudiments and Attempts are involved in obscurity and deep night. and so pcrplext with subtilties, that they delude the most piercing wit, as well as the sharpest eye. Nor can we easier discover the secret recesses, and dark principles of Generation than the method of the fabrick and composure of the whole world. In this reciprocal interchange of Generation and Corruption consists the Eternity and Duration of mortal creatures. And as the Rising and Setting of the Sun, doth by continued re- volutions complete and perfect Time; so doth the alternative vicissitude of Individuurns, by a constant repetition of the same species, perpetuate the continuance of fading things.

Those Authors which have delivered any thing touching this subject, do for the most part tread in several path, for having their judgements pre- possessed with their own private opinions, they proceed to erect and fashion principles proportionahle to them.

Aristotle of old, and Hieronymus Fabricius of late, have written so accur- ately oonccming the Formation and Generation of the I-‘oetus out of the Egge, that they seem to have left little to the industry of Posterity. And yet Ulysses Aldrovandus hath undertaken the description of the Pullulation or Formation of the chicken out of the Egge, out of his own Observations; wherein he seems rather to have directed and guided his thoughts by the Authority of Aristotle, than by his own experience.

For Volchcnis Coiter, living at Bononia at the same time did by the advice of the said Aldrovandus (whom he calls Tutor) dayly employ himself in the opening of Egges sat upon by the Hen, and hath discovered many things truer than Aldrmandus himself, of which he also could not he ignorant. Likewise }Emilius Parisanus (a Venetian Doctor) dcspising other men: opinions hath fancied A new procreation of the Chicken out of the Egge.

But because somethings, (according to our experience) and those of great moment and cons: . I aha" dad“: to yo°fi‘;;l°:t: ;;;!yt1\lrt:i ozlstserwrse hath been yet delivered, are altered. especially about the Emzfhyelas $21 [cl éunbthe cgpc. a.nd.wh1.t mm thnlnhgs age znhost intricate, confused, and hm‘ to 05;’-:‘v’::;:<;v;h!r)e°h‘ au tars o iefl sticlrle ' - .

‘ P. 77 of the English edition (1653). x17 A msronr or emanrotouy

rather to their oi;-n pmoiaour-rcem

than to ixiicihieliicaiiirlil M m°‘°“‘ Cm“ °‘ “" emenfion of Animals)

Aldrovandus, artakin

but a blind mznlizn mbsgcr‘?ith‘ehteo3ainh:¢eg'},1:'ryY:,1l!klidA[)3I5‘Pu"]; “gm ((‘1"h"h “".“° to the Acute Angle of the Egge; and thinks the Grnrrdil esct ii Eynsécism the Cock: and that the Pulius isrramcd out ufthcm bui",,o..:;,h,§ :5 my 1?! the yolk as the white; which is clean contrary to Aristotle’: o irrioo who our: awed the Gnndines to oonduec nothing to the feeundip of ,the Vcldrerus Coiter delivers truer things, and more oorsanzmt 3 Auto ‘egg. his three Globuli are meer fable. Nor did he rightly consider the from whence the Foetus is derived in the Egg. Hieronymus 1-‘;b,g,_-in}; ;...,.':§ contends, that the Grandine: are not the seed nfthe cook and yet he will have the body of the Chicken to be framed out of them (as oht cfits firs: matter) being made fruitful by the seed of the cock. He likewise saw the Original of the Chicken in the Egge; namely the Macuia, or Cimtr-icuiz annexed to (L: membrane of the Yolke, but conceived it to be anely a Relique of the stalk broken off, and an infirmity of blemish onely of the Egge, and not a principle part of it. Pnrisanus hath plentifully umiuted Fabricius his opinion concern- ing the Chalazae or Grandines, and yet himself is evidently at a loss insarne ocrtnme circles and point: of the Principle parts of the Foetus (namely the Liver and the Heart) and seem: to have observed a Principiurn or Principle of the Foerus, but not to have known which it was, in that he saith, that the Puneturn Album in the Middle of the Circle: is the Cocks Seed out of which the Chicken is made. So that it comes to pass that while each ofthtan desire to reduce the manner of the Formation of the Chicken out of the Eggc

to Lheir own npinions they are all wide from the mark.

Before discussing how Harvey put them right. however, there are a number of other matters to be mentioned. Parisnnus’ work was pub- lished in 1623, and twenty-five years were to elapse before Harvey’: Exercitatioru were to be put before the learned world by George Eat. In that time not a few events of importance for the history of embryology took place.

It will be cunwnimt to speak fits: of Adrianus Spigelins, whose De Formula Foeiu appeared in 1631. In this hook the plates of the gravid uterus which had been prepared some years before for Julius Casseriux were now published. They had more influence than Spigelius' Km. perhaps, in contributing to the permanent fame of his book.

He gives for the most part straightforward anatomical descriptions.

but he returns to the notion of a cotyledonous placenta in man, and he combats Ar:tntius' opinions about the placenta. Arantius had said that the function of the jecor men‘ was to purify the blood—supply to the foetus, a thoroughly modern idea, but Spigelius opposes this on two grounds, firstly, because the foetus has its own organs for purifying blood, and secondly, because. if Arantius was right, the placenta would always be as red as blood, but this is not the ease in such animals as the sheep. Spigelius himself thought that the placenta was for the purpose of preventing severe loss of blood at birth, as would be the case if the embryo was joined to the mother with only one big vessel and not a great many little ones.

However, Spigelius upholds the view, taken by Rufus of Ephesus and by Vesalius, that the allantois contains the foetal urine, which has to be separated from the amniotic liquid in which the embryo is, because it would corrode the embryonic skin (71: cult" tenellae aliquot! dunmum urinne animonia infmet). The first discussion of the oernix mseom, or mrder, as he calls it, appeals in Spigelius, who, however, hazards no guess as to its nature. He is happy in his refutation of Lzurentius, who had aflinned that the foetal heart did not beat in umo, and he shows some advance on all previous writers save Arantius in declaring that the umbilical vessels take vital spirits away from the foetal heart, not ex- clusively to it. He gave, moreover, the first denial of the presence of a nerve in the umbilical cord, and also made the first observation of the occurrence of milk in foetal breasts at birth.‘ Finally, he abolished at last the notion that the meconium in the foetal intestines argued eating in mm: on the part of the embryo.

Riolanus the younger,‘ the correspondent and almost exactly the contemporary of Haney, was professor in Paris and published his Anthropogruphfa in 1618. As he was a keen advocate of the ancient views, his section on the formation of the foetus has little importance. Yet it contains the first known instance of the use of the lens in embry- ology, the germ of that powerful instrument which was to lead in due course to so many discoveries. “In aborted embryos," said Riolanus, “the structure is damaged and can often not be properly seen, even when you make use of lenses (conxpidlia) which make objects so much bigger and more complicated than they ordinarily seem.”

The De Fanmrlrice Faetu: of Thomas Fienus, professor at Louvain and a friend of Gassendi, published in 1620, is interesting because it is the middle term betuecn Aristotle and Driesch. As the title-page informs us, he sets out to demonstrate that the rational soul is infused into the human embryo on the third day after conception. This by itself would not be very am-.1c¢iv'e but the most cursory inspection shows that Fienus’ interests were nizt at all theologit‘.-1L He divida the hook up into seven main questions. (1) What is the eflicient cause of an- bryogcny? He concludes that it is neither God, nor Intelligence. nor anima mundi (influence of neo-Platonism here as on Galileo). (2) Is it in the uterus or in the seed P In the latter, says Fienus, adding a list of authorities who agree with this view—I-Ialy-Abbas, Gaictanus, Zon- zims, Turisnnus, Fernelius, Vallesius, de Perunato, Saxonia, Czsrrcnllf. Zegnrm, Mercurialis, Massazia, and Archangelus, "rolru Fabio Ifaua men; impmdrnler udxmfiit" (I). (3) Is it heat? lixenus nearly deczded that it was, but gave his opinion against It. _saymg. “tl1e‘P}'°°63 (°f development) is so divine and wonderful that it would be ndxculous to ascribe it to heat, a more naked =_md Simplt qll-11“?-" Mm’ ‘WEh'”8 various other alternatives in ql-ICSHOHS (4): (5)311?! (5). 116 355 “'h°d‘°_‘ it is anirmz rnnimlr port emutplum adtemnu (7), and concludes that; is. 1: is here one he Mwm:1nfl§m:Y:‘mg-_f°Eh;Q:f;“ "- npprovnl certain writers, e.g. exzn er P °d‘5’f _‘’’4{ ' ‘,”'7,'“

‘ The endocrinological Aspect: of the no-mlled "soreerer’r milk" luv: been studied by lhlban and it has been unlysed by Tuchnssovnilmv. ‘ See Donlry:

- 1, ' 1 ' -exuter: orgimxzahorn), Themxstzus Si‘:-:§;Z;,:fZ:,,::}:3g:z,?:;;fgfdmnidbilm ct ac:om1r,r;o;1a,!ur;' flu"!!- mentmn) and Marsilio Fit.-mo in‘ his con._tmf!}¥31'Y °{' 3 “S "”"""d (pyiusguum adullum sit corpus. WW6 310 |31I"‘“{f¢§’;‘“°}:f;"f:‘r:2;‘;

- - ‘ h ' 3 mm c w I

‘i,'"i,"§m:m:i can't‘-Ir;-nbgixigearstocrglasn fo1?eachPof its faculties and ‘ 5 G‘ y wn resiclenoe not merely OODWWIHB 7° 1” b"”“‘°d i“’°’ gffiigiéiig which has nlieady organised itself. “The confonnazion of

a the foetus 1.: a v|tal,fn;t °a§Ii::,;'°1;:¢:d°;_i‘:P;g;:]’fl: intheremaindero 2 e :3 ' _

after which the mtmnal (not V'9Sf3'3u"e °’ ‘ms’ '_° . bl of ‘ d the uterus with the seed, finding a suite e mztss

whmh has mmiel ters into it and begin’ m El“? it 3 shape‘ Flam’ izipealtficligcg; ’s::enl writers, 3113 P“w5b‘d 3 ddmce °£ his views. A . _ . . T -chm Later wnters on $e Sa;I1[a‘c"5lIl‘:]x:§Idx:1(itI1ed:gofll§Cr§;e Scganhfiygz Albertus de Reies, one ' ‘I-‘Ii . ' . ,1] W am p«m»s.sxswfism*- ¥*‘°;°*;“:.:::L:;=:;*:.“:;.:.: adopted the same standP°1"‘ 35 menus "1 I 5 ’

In 1625 Joseph de Arornatari, of Assisi, included in his epistle on plants the first definite statement of the prefomtatianist theory since Seneca, but he did not develop the idea.‘ He had noted that in bulbs and some seeds the rudiments of many parts of the adult plant can be seen even without glass or microscope, and this led him to suggest that probably in all animals as well as plants a similar thing was true. “And as for the eggs of fowls," he said, “I think the embryo is already roughly sketched out in the egg before being formed at all by the hen (quad attinet ad ova gallimmnn, zxirtimamu: q-m'd'em pullum in «ma delinealum em, antequam fooeamr a gaIlx'na).” This suggestion did not begin to bear its malignant fruits till the time of Swammerdam. In his De Rubia Contagiara, too, Ioseph de Aromatari wrote against spontaneous generation, asserting that all animals arise from eggs (Bigelow). Here the logical connection between preformationism and belief in spontane- ous generation appears, as also in its converse later, eg. when, in the thought of I. T. Needharn, epigenesis and spontaneous generation go side by side (see on, pp. 211 and 218).

Johannes Sinibaldi's Geneanlhrapia might be mentioned as belonging to this time. It was a compilation of facts relating to the generation of man, but it expressly excluded from its field any discussion of the embryo. It is no more important for our subject than the queer Om’ Enmmium of Eryeius Puteanus, another of Gassendi'5 friends.

2. Developmental Determinism and Transplantation; Digby,.

Highmore and Tagliacozzi

Much more significant was the controversy between Sir Kenelrn Digbyi and Nathaniel Highmore. in 1644, Sir Kenelm, whose intrigu- ing personality will be sufficiently familiar to anyone even slightly ac- quainted with seventeenth-century England (biographic details in I ohn Aubrey and in Bligh), published a work with the following title:Two treatirer, in the one of which, The Nature of Bodies, in the other, The Nature of1lIan'.r Soul: 1': locked into, in may afdircozvry oftlre Immortality of Reasonable Souler. It was inscribed in a charming dedication to his son, and consisted, in brief, in a survey of the whole realms of metaphysics, physics and biology from a very individual point of view.

One of Sir Kenel.m’s principal objects in writing apparently was to attack the old terminology of "qualities" in physics and “faculties” in biology. To say, as contemporary reasoning did, that bodies were red or blue because they possessed a quality of redness or blueness which

‘ See pp. 66, 163 and zrg. ' See Plate Vll, {sting page rzz. X2!

caused them to appear red or blue to us, or again, to say that the heart beat because it was informed by a sphygmic faculty, or, to take the famous example, that opium sent people to sleep because it contained in it a dormitive virtue, appeared mere nonsense and wurd»spinning to Digby, “the last refuge of ignorant men, who not knowing what to say, and yet, presuming to say something. do often fall upon such cxprastons.

Digby, like Galileo and Hobbes, wished to explain all phenomena by reference to two "virtues” only, those of rarity and density, “tracking by means of local! Motion." Chapters twenty-three, twenty-four and twenty-five contain his opinions and experiments in embryology. He begins by opening the question of epigenesis or prcformation, practi- cally for the first time since Albert the Great. "Our main question shall be," he says, “whether they be framed entirely at once, or successively, one part alter another? And if this latter way, which part first?" He declaru for epigcnesis, but after n manner of his own, refuting "the opinion of those who hold that etrerything cantaincth formally all things.”

Why nhould not the part: be made in generation [he ask] of a matter like to tlm which tnaketh them in nutrition? If they be nugrnented by one kind ofjuyce that after nvcnall changes turneth It the length into flesh and bone; and into every tort of mixed body or limiill’ part “hereof the sensitive era- ture is compounded, Ind that joyneth itself to what it findeth there already nude, why should not the nine juyce with the some progress: of heat and moisture, and other due temperaments, be converted at the hm into Bash and bone though none he formerly there to joyn it self unto?

He gave a clearly deterministic account of development.

Take a bean. or any other seed and put it in the earth, and let w:ter_f2ll upon it; can it then choose but that the bean must swell The [Wan 8W¢u1“E- can it choose hut break the skin? The akin broken. can rt ch°°§= (by {tam of the heat that is in it) but push out more matter, and do that action wind: we may call genninnting? Can these germs choose but pierce the earth in strings, an they are able to make their way? . . . Thus by drawing the thrtd cm,“-“Hy along through yam fingers, and staying at every knot. to examine how i; is tyed; you see that this diflicult progress: of the generation of lmng creature: is obvious enough to be comprehended and the steps of it set down; if one would but take the paines and afford the time that is neossary to note difigcnflygu the circumstanots in every change pf it. . . . Now if all this orderly succession of mutations be necessarily made in a ban, by force of sundry circumstances and external! accidents; why may itnot be conceived that the

I on dais pampern-mic view, lee pp. 66 and 79- 1 22 PLATE VH

Sir Ktntlm Dtgby (_/rum thz pamllng by Camzlnu Janxrn. at Ahlmrp. Copying/1!: Earl Spenm).

like is also done in sensible creatures, but in a more perfect manner, they being perfeaer substanomi Surely the progress: we have set down is much more reasonable than to conceive that in the seed of the male there is already in act, the substance of flesh, bone, sinews, and veins, and the rest of those severall similar parts which are found in the body of an anirnall, and that they are but extended to their due_magnitude by the humidity drawn from the mother, without receiving any substantial mutation from what they were originally in the seed. Let us then confidently conclude, that all generation is made of a fitting, but remote, hornogeneall compounded substance upon which outward Agents, working in the due course of Nature, do change it into another substance, quite different from the first, and do make it lesse hornogeneall than the first was. And other circumstances and agents do change this second into a third, that third, into a fourth; and so onwards, by successive mutations that still make every new thing become lessc homo- geneall than the former was, according to the nature of heat, mingling more and more different bodies together, untill that substance bee produced which we consider the period of all these mutations.

This passage is indeed admirable, and well expresses the most modern conception of embryonic development, that of the ovum as a physica- chernical system, containing within itself only to a slight and varying degree any localisation answering to the lomlisation of the adult, and ready to change itself, once the appropriate stimulus has been received, into the completed embryo by the actions and reactions of its own con- stituents on the one hand and the influence of the fitting factors of the environment upon the other. Digby has not received his due in the past; he stands to embryology as an exact science, much in the same relationship as Bacon to science as a whole.

Generation is not made [he says] by aggregation of like parts to pre- supposed like ones; nor by a specifical Worker within; but by the compound— ing of a seminary matter with the juicc which aocrueth to it from without and with the steams of circumstant bodies, which by an ordinary oourse of nature are regularly imbibed in it by degrees and which at every degree doe change it into a different thing. . . 3 Therefore to satisfie ourselves herein, it were well we made our remarks in some creatures that might be continually in our power to observe in them the course of nature every day and hour. Sir John Heydon, the Lieutenant of his Majesties Ordnance (that generous and knowing Gentleman, and consummate Souldier both in theory and practice), was the first that instructed me how to do this, by means of a furnace so made as to imitate the warmth of a sitting hen. In which you may lay severall eggs to

‘ Digby would have appreciated the dernorut-ration of modern biology that the egg: of many animals eontain insuflicxent water and salt: for the embryos produced from them, ):o that absorption from the environment has to take place (see Ncedham. I9] r, 1:. an .

hatch and by breakin th t u ‘ ' hourli’ mutation in thgem iafnyguslfilrahac. ages you my dmmcfly obuwcaeq

_SI1' Ixcrlclm then on to describe the events that take place in the incubating egg, which he does very accurately. though briefly. Invi ‘. Pm, he Sara. the like experiments have been made, and the like con- clusions come to by "that learned and exact searcher into nature, Doctor H:1rvey"—these he niust have learnt of by word of mouth, for Harvey’: book had not at that time been published, As regards heredity,headopts a pure theory of pangenesis, and has more to say about it than any other writer of lug time. He is sure that the heart is first formed bothin Ovi- P3” and VmpaI_'-4. "whose motion and manner of working evidently appears in the twmckling of the firs: red spot (which is the first chnnge) in the eggs.”

Sir Kenelm Digby not only anticipated the outlook of the physica- chemical emhryologist, but he also foreshadowed with considerable acumen \ViIhelm Roux's definition of interim emhryologiml lam.

Out of our short survey of which (ansenble to ourweak talents, and slender experience) I pemvade myself it appeareth evidently enough that to effect this worlte of generation there needeth not to be supposed a fomiing virtue or Vi: Fonnotrix of an unlmown power and operation, as those that consider things suddenly and in gross: do use to put. Yet in discourse, for eonvcniency Ind ahortnesae of expression we shall not quite banish that tune from all commerce with us; In that what we mean by it be rightly understood. which is the complex nsaernbleznerat, or chain of ‘Ill the noses, that concur to pro- due: this effect. or they Ire set on foot to this end by the g1’eatA.rchi!cct xnd Modentuur of them. God Almighty, whose instrument Nature is: that is, the nine thing, or rather the some Lhings so ordered as we have declared, but expressed and comp:-ized under another name.

Thus Sir Kenelm admits that it is allowable to speak of the "complex assemblement" of causes, as if it were one formative virtue, and this corresponds to Roux‘s “secondary components" or interim embryo- logical laws. But that the portmanteau genernlisatiuns an be resolved into ultimate physieo—chemical processes, Dighy both believa and spends two entire chapters in trying to show. Digby has been one of the two seventeenth-century Englishmen most under-estimated tn the history of biology, but his place is in reality a very high one. How far he was in advance of his time may be gauged from the worl: of his con- temporary Spcrlingen, whose book of 164x was thoroughly scholastic and retrograde.

His Trealire on Eadie: evoked several answers. Undouht.e<lly.the most interesting from the progressive side was that of Nathaniel Highmore,‘ who will always be well remembered in embryological history. Highmore’s The History afG‘eneraIz‘on came out in 1651, so that Harvey must have known of it, and it is one of the puzzles of this period why Harvey made no mention of it in his work, apecially as I. D. Horst in a letter to Harvey refers to Highrnore as his pupil. Harvey replying in 1655 said he had not seen Highrnore for seven years. Hlghmure'a title- page expressly states that his book is an answer to the opinions of Sir Kenelm Dighy. But before discussing in what the answer consisted, we may look at the plate which is bound in immediatelyafter the dedication (to Robert Boyle). It is interesting in that it shows again the idea initiated by Leonardo, namely that all growing things, plants as well as animals, have an umbilical cord. But the drawings of the chick embryos and eggs are more quaint than accurate (Fig. rr).

Highmore first describes the Aristotelian doctrine of form and matter, and then cenaurcs both it and the extensions of it with their “qualities," etc., much as Digby himself had done.

Some of our later philosophers have showed us that those forms war“ they thought and taught to bee but potentially in the matter, are there actually subsisting, though till they have acquired fitting organs they manifest not themselves. And that the effects which were done before their manifestation (as the forming and fashioning of the parts wherein they are to operate) can rise from nothing else than from the Soul itselfe. This likewise I shall leave to the Readers enquiry, and shall follow that other way of introducing Forms, and Generation of creatures (as well animals M vegetables) which give: Fortune and Chance the prehemincncy in that work.

He then describes Sir Kenelrrfs opinions, quoting from him in detail, and dissents from them mainly on the ground that they do not sulfi- ciently account for embryogeny, as it were, from a technical point of view. That they subvert the "antique principals of philosophy" does not worry Highmore, but in his view their detailed mechanisms do not. explain the facts, a much more serious drawback. Highmore is himself by way of being an utomist, and it is because embryology was first treated by him from an atomistic standpoint that he derives his importance.

The blood, that all parts may be irrigated with its benigne moisture, is forc'd by several channels to run through every region and part of the body; by which meanea every part out of that strum selects those atoms: which they find: to be cognate to themselves. Amongst which the Testicle: abstract some spiritual atomes belonging to every part, which had they not here been anticipated, should have been attracted to those pom, to which properly they

' Phylieinn It Sherborne in D'or:e4, see Fig. I2. I25 XI. Illurlrutfvnfrvm Nalhanill ”i:hMW('l "Hittory of Gtncntion," X651. 1 26 EMBRYOLOGY IN THE SEVENTEBNTH CENTURY

did belong for nourishment. . . . These partiel passing through the body of the Testides, and being in this Athanor oohobsted and reposited into a tenacious matter, at last passe through infinite Mmnders through urtain vessels, in which it undergoes another digestion and pelimniziug.

Highmore objects, therefore, more to Digby’s theory of pangenesis than to his description of embryogeny. He gas on to give a long descrip- tion of the development of the chick in the egg. mentioning in passing that the albumen corruponds tnthe semen and the blood of Vivipara. and the yolk to thdr milk. ‘

Fahritius, who hath taken a grunt deal of pains in dissections . . . suppose: the chick to he formed from the chalame, that part which by out Women is ulled the treddle. But this likewise is false. for then every egge should pru- duce a chickens, there being one treddle at each end of the egg. Which “"9 for no other end than for ligaments to contain the yolk in an equilibrium. that iélmhhtnothyeverymovingoftheggbeshakt, hrokqaudeoufitsodwith

e white.

Highmore was the first to draw attention to the increase of brittleness which talus place in the egg-shell during incubation,‘ and he holds still to the Epicurean view that the female produces a kind of seed,‘ though he thinks that the chick mnbryo is nourished in the early stages by the amniotic liquid.

Perhaps the most interesting reply to Dighy from the traditional angle was that of Alexander Ross. In his PIn1ocopln'call Tourhrtane he upheld the Galenic View that the liver must be first formed in genera- tion, for the nourishment is in the blood and the blood requires a liver to malre it: ergo, the liver must be the earliest organ. Sueharguments could dispense with observations. Ross also mentions Digby's sug- gestion that the "forrnative virtue" was only a bundle of natural causes, but he claims that the notion was an old one in schoohphilosophy, being included in the phrase mum azume, mum causati.

It was said above that some of Digby's idms anticipated the formula- tions of one of the greatest founders of modern experimental embryo- logy, Wilhelm Roux. The most fundamental technique of modern experimental embryology is undoubtedly that of the transplantation of parts of embryos into dilfererrt situations in other embryos. The problem for which it was developed by Gustav Born and Hans Spe- xuann was that of "determination," or the own of the fixation of the fate of parts and tissues. Will they develop, in their new environment,

figlltebglloseslhoulypetcenl.nfiulimetolheinltrinrdnringhrurhttinm p. .

In accordance with their original presumptive fate, or in accordance with that of the tissues of the host which immediately surround them? The first type of behaviour acquired the name herlzunflrgenuirr (or in English, "selfu1se"); the second came to be called ortsgernixr (or in Ejlgltsll. "neiglIbourwise"). As is well known, It vast branch of modern b|0l0g}’» which may be called aperirncntal morphology (equivalent to the German Enluiclzlungrmechaliik), has grown up since the time of W. Roux (I850-I924), and has achieved many points of contact with bio- fhenirsuy.‘ The study of the morphogenetic hormones, or organisers. is being actively pursued today.

‘In the light of these facts it would be very desirable to have a system- atic monograph on the history of transplantation and grafting in general, but if such a treatment of the subject exists, I have not been able to find it.‘ Certainly grafting and transplantation have a long history, but because easie: in plants than in animals. and in large organisms than in small embryos, they did not quickly lead to funda- mental discoveries. Moreover, in adult organisms, immunity reactions prevent the success of any but autoplastic transplantations (i.e. from place to place on the same animal). These were. however, known in the sixteenth century, as Con-adi has described, and (according to Garrison and othets) may be traced to ancient Indian surgery.

In the seventeenth century the concepts of "selfwise" and "neigh- bounvise" were closely approached, though in a setting of factual error, as we find from an amusing story related by Walter Chztrleton in 1650.

A certain inhabitant of Bnnels, in a combat. had his nose mowed on, and addressed himself to Tagliaoouus,' I famous Chirurgeon, lining at Bononili that he might procure a new one; and when he feared the incision of own arme, he hired a Porter to admit it, out of whose mm. l-raving’ first gush the reward agreed upon, at length he diggcd a new nose. About tlrrrtwn monflhs after his return: to his cwne countrey, on n suddaine the ingr-a'lted_nnse grew cold, putrified, and within a few days dropt all’. To those of his fnendl. 9131 were curious in the exploration of the cause of this unexpected misfortlmfii it was dismvered, that the Porter expired near about the same punculrc of time, wherein the nose grew (rigid and tatdaterous, There are at Bnrxnlfi Y“ surviving, more of good repute, that were eye-t'ritn6ses_nf thee occurrences. Is not this Magnetisme of manifest aflinity with rnumle. Wl1¢“l’Y “W “W-

mm 0ppmh¢iii:(e'.°5§) ma techniques in ernbryology. _ , ch. . an ‘,,,,,,, Renaissance. Cluflw l’l=h‘6;zr¢ery' 599): lll7'Aezl(a:;11'I!l: may or his and tuna we are indebted to Guudr dc tvebuex.

I28 Fig. 12. Nalhanitl Higlxmou, M.D.

(from the m1,.,ag. of an “Corpons lmmnni dusqmsmo amalomia," 1651).

Fig. 1.1. Rm! .1. Gran]. M.D. am. In‘: «open mm.

We and right of inoculation, a community‘ I lif ‘mi V=§='-‘flI0n. 70! so many nmneths, nu a suddaine rnnniliethbn ti: side

h na}tl$sI1 I is therein mi: of Superstition? What ufatrmt The bookinwhichthis storywas related was entitled:A Ttmayn Pmdow: The Mqnztitlf cm of Wauntlr, 77» Nam-‘xy of Tartar"; 775": 771: Image of God In Illm; tnillul anyway by }olL Bap; an Helmanl, and Ibwulalnd, Illuxtmled, all Amplialed by Walter Charle- ton. Charletan was a friend of Kenclm Digby's, and mention; him in hrs Prnlegtrrntrra.The ngervasnrneinwhidxmenweremuchfascinated by magnetic phenornena such as had been described at the beginning of the century in “’ilham Gilbert's worlr on the lodutune (1600). The century was to end, moreover, by the triumph of the concept ointme- tion embodied in Newton's work on gravitation. It is therefore not in the lust surprising that the biologists in the intuvening period should have thought a grant deal about action at a distance. and if their beliefs were sometimes rather absurd by pr-esent—dzy standards, this must aftcralltosomeextentbeduetothegrtatinhexent difiicultyofhiu- logical experimentation. Dighy and Char-leton, no less than van Helo mnnt. believed in the possibility of a "magneti " cure of wounds, the patient benefiting by the application of preparations to the sword which had aused the hurt, or the bandage which had first covered it. Hence the relevance of the transplzntatimr story, which Chzrktnn emphasized again in his Prulegornena, saying that he would relate

hnwa'l‘agliaartianNose,enfeoifedwithaCnmmunityufV'mlityand Vegetation, by right of Transplantation, upon thefieenf: Gent. at Bmxels h:thgruwnendavermr:anddrnptnfl':ttheinstanceofthztPonn’:death infianoniaontofwhosearmeilwasfirstrnected.

This was an effect “rnagneti " due to "the long urine of Syrnp:thy_." Allthiswastakenquitee¢riuuslywhentheRoyal Socletybeganlts worl: a decade later, and a special invatigation was made of ‘:Srr Kenelrn Digby’s Syrnpathetimll Powder for the Cure of \Vapnds.’ Significant also is the fact that both Charleton and Drgby were interuted intherevival of atonrism. They hoped that the rapid ‘travel of "pcstilenti.-:1! Atomcs,“ “igneous Amines." “mumiall ;5‘"mB- ' 3"“ me like, might some day the phmmnma ofattnctran Ind achml

at a distance. . _ _ But the point ofinterest for us is the Idea that a piece oftransplznted

tissue could long retain, though inmrpor-ated into the body of a host, pmpertia belonging to the body from which it had been taken.

3. Thomas Browne and the Beginnings of chemical Embryology

There are references to embryology in Sir Thomas Browne’s Pseudo- daxia Epidemica, or Inquiries into very many vulgar T went: and cam« manly received Trutlu, which was published at this time.‘ The twenty- eighth chapter of the third book contains a number of diflicult problems in the embryology of the period, in most cases stated without any solution.

That a chicken is formed out of the yolk of the Egg was the opinion of some Ancient Philosophers. Whether it be not the nutrient of the Pullet may also be considered; since umbilical vessels are carried into it, since much of the yolk remaineth after the chicken is formed, since in a chicken newly hatched the stomach is tincted yellow and the belly full of yelk which is drawn at the navel or vessels towards the vent, as may be discerned in chickens a day or two before exclusion. Whether the chicken be made out of the white, or that be not also its aliruent, is likewise very questionable, since an umbilical vessel is derived unto it, since after the formation and perfect shape of the chicken, much of the white remaineth. Whether it be not made out of the grando, gallaturc, germ, or trecl of the egg, as Aquapendente informeth us. seemed to many of doubt; for at the blunter end it is not discovered after the chicken is formed, by this also the white and the yelk are continued whereby it may 0011- veniently receive its nutriment from them both. . . . But these at last and how in the Cioatriculs or little pale circle formation first beginneth, how the Gr-ando or tredlc, are but the poles and establishing particles of the tender membrnns firmly conserving the floating parts in their proper places, with many observables, that ocular Philosopher and singular discloser of truth, Dr Harvey hath discovered. in that excellent discourse of generation, so strongly erected upon the two great pillars of truth, Experience, and Reason.

That the sex is discernable from the figure of eggs, or that rocks or hens proceed from long or round ones, experiment will easily frustrate. . . . Why the hen hntcheth not the egg in her belly? Why the egg is thinner at one extrearn? Why there is some uvity or emptiness at the Hunter end? Why we open them at that part? Why the greater and is first excluded 2’ Why some eggs are all red, as the Kestrils. some oniy red at one end, as those of kites and buzzards? Why some eggs are not oval but round, as those

of fishes? ete., are problems whose decisions would too much enlarge this discourse.

And elsewhere,

That [saith Aristotle] which is not watery and improlifical will not con- glaciate; which perhaps most not be taken strictly, but in the germ and spirited particlespfor Eggs, I observe, will freeze, in the albuginous part thereof.

I See Merton. ' Cf. Needhatn (1931), p. 231.


They who hold that the egg was before the h‘ d this ,1 ~ mm)’ Other animals, which also exteridcth unto thexun;’t’:iE are noiiiiiglhfi by urnhrlical vessels and the navel is manifest sometimes a day or two after exclusion.‘ . . . The same is made out in the eggs of snakes, and is no: im. probable in the generation of Porwigglm or Tadpoles, and may also be [rug "' 5°m° "“mP‘"°“3 5X‘—‘1“310M. lllllough (as we have observed in the daily Pm?” °_f §°m°) the whole Magot is little enough to make a fly without any part . . . The vitreous or glassie flegm of white of egg win gin“. extinguish a coal.

These citations show Sir Thomas to have been more than simply the supreme artist in English prose, which is his common title to remem- brance. In picking way carefully among the doubtful points and difficult problems which previous embryologists had propounded but not answered, he usually managed to give the right answer to each. But in addition to this, he was also an experirnentalist, he had made both anatomical and physical aperiments on eggs, and he was prepared to put any disputed point to the tst of "ocular aspection," if this could be done. His experimental contributions to embryology come out more clearly in his Commanplate Bank: which were puhlikhed by Wilkiri in 1836.

Runnet beat up with the vi-hits of eggs seems to perform nothing, nor

will it well incorporate, without so much heat as will harden the egg. . . .

Eggs seem to contain within themselves their own coagulum, evidenced

upon incubation, which makes incrassation of parts before very fluid. . . .

Rotten eggs will not he made hard by incubation or deooction, us being destitute of that spirit or having the same vitiated. . . . They will he made hard in oil but not so easily in vinegr which by the attenuating quality keep: them longer from concoction, for infused in vinegar they lose the shell and grow hig and much heavier then before. . . . In the ovary or second cell of the matrix the white comes upon the yolk, and in the later and lower part, the shell is made or manifested Try if the same parts will give any coagulation

unto milk. Whether will the ovary best? . . . The whites of eggs drenched in saltpeter will shoot forth a long and hairy saltpeter and the egg become of a hard substance. Even in the whole egg there seems a great nitrosity, for it is very cold and especially that which is without a shell (as some are laid by fat hens) or such as are found in the egg poke or lowest part of the matrix. if an hen be killed a day or two before she layeth. . . . Diflerence between the sperm of frogs and eggs, spawn though long boiled, would not grow thick and magn- late. In the egg: of skates or thornhacks the yolk coagulates upon long deooc- tion, not the greatest part of the white. . . . In spawn of frogs the little black speclts will concrete though not the other. . . . In eggs we observe the wlute will totally freeze, the yolk, with the same degree of cold will grow thick and


Sn Thmmz: Bnm-nz and kit tuft, Dorothy (from the panmu junnzrly an the pasreman of the Am:/am7, at Srmfilmm Paar 4. T.u.;I.;.).


Gulichlwi Harircufi

_Gcucx-atione ..AJll:ll}<1lillfl;. .' , Zau I.zma:;..g Inirlg bang: from an cg (III:/wnlupiru 0/ 1:3:/rm Hart 4-‘: back .». Ilu Gmrruian cf Ammals. 1651).

clammy like the gum of trees, but the sperm or tread hold its former body, the white growing stiff that is nearest to it.

The only conclusion that can be drawn from these remarkable ob- servations is that it was in the "elaboratory" in Sir Thomas’ house at Norwich that the first experiments in chemical embryology were under- taken. His significance in this connection has so far been quite over- looked, and it is time to recognise that his originality and genius in this field shows itself to be hardly less remarkable than in so many others.‘ To study experimentally the chemical properties of those substances which afford the raw material of development was a great step for those times. It was not until some twenty-five years later that \Valter Need- ham carried this new interest into the mammalian domain.

4. William Harvey and the Identification of the Blastoderm

The Latin edition of William Harvey's book on the generation of animals appeared in 1651, and the English in 1653. The irontispiece of the former (which is reproduced as Plate IX, opposite) is a very noteworthy picture, and derives a special intertst from the fact that on the egg which Zeus holds in his hands is written Ex ova omm‘a——-a con- ception which Harvey is continually expounding (see especially the chapter, "That an egg is the common Original of all animals"), but which he never puts into epigrammatic farm in his text, so that the say- ing, omne vivum ex am, often attributed to him, is only obliquely his.

The De Generation: Animalirzm was written at diflerent times during his life, and not collected together for publication until George Ent, of the College of Physicians, persuaded Harvey to give it forth about x65o. As early as 1625 Harvey was studying the phenomena of embryology, as is shown among other evidences by a passage in his book where he says: ‘

Our late Sovereign King Charles, so soon as he was become a man, was want for Recreation and Health sake, to hunt almost every week, especially the Buck and Doc, no Prince in Europe having greater store, whether wand-

’ See Plate VIII, facing page :31. I may give two instutou of Browne’: awareness, isolated though he may have been at Norwich:

(r) The Ilydriulaphia was first published in r658. In chapter 5 occurs the famous "Life is A pure flame; we live by an invisible Sun within us." The Traclam: Duo of Mlyow to whom the firs: experimental demonstration of this is usually ascribed. was pu lished in 1668. Patterson, however, shows that it may be found in la’: Spring and Weight of the Air, 1660. May we not conclude lhll Browne was in airly close touch with the Invisible College. fint mentioned in I646?

(a) Dr Sin 1' tell: me that Browne was acquainted with the very ml’: work of Cesi on wore: in erm, of which no copy has been in England for many yean.

‘ P. 396; this and subsequent references are to the English edition of 1653.

133 A ms-roar or EMBRYOLOGY

ring at libe in the Woods and Forrests or in l '

and Chaceslfyln the three summer moneths thee aalfldtllihpetgcgglgeplirges then {at and in season were his game, and the Doe and Hind in the Autummi and Winter so long as the three seasonable moneths continued. Hcreupon I had d_axly opportunity of dissecting them and of making inspection and ob. ‘°":“u°“ °f an ‘hm’ P31’?-S. Whlcil liberty I chiefly made use of in order to the genital parts.

Nor was Harvey less diligent in examining the generation of Ovipara. John Aubrey, in his Bn'efLr'z'e:, says,

I first sawe Doctor Haney at Oxford in 1642 after Edgehill fight, but I was then too young to be acquainted with so great a Doctor. I remember that he mm: often to Trin. Call. to one George Bathurst, B.D. who kept a her: in his chamber to hatch egges, which they did dayly open to discerne the progress and way of geueratiom

Aubrey mentions a conversation he had with a sow-gelder, a oountry- man of little learning but much practical experience and wisdom, who told him that he had met Dr Harvey, who had conversed with him for two or three hours. and "if he had been." the man remarked. "as stiff as some of our starched and formal! doctors, he had known no more than they." Harvey seems also to have learnt all he could from the keepers of King Charles’ forests, as several passages in his book show. Nor was the King‘s own interest lacking.

I saw long since a foetus [Harvey says] the magnitude of a peaseood cut out of the uterus of a doe, which was complete in all its members «Se I showed this pretty spectacle to our late King and Queen. It did swim, trim and per- fect, in such a lrinde of white, most transparent and crystalline moysture (as if it had been treasured up in some most clear glassie receptacle) about the higuesse of a pigeon’; egge, and was invested with its proper coat.‘

And, again-

My Royal Master, whose Physitian I was, was himself much delighted in this kinde of curiosity, being many times pleased to be an cye—witnes!, and to assert my new inventions.’

Harvey's hook is composed of seventy-two exercitations, “W15” 1'53)’ be divided up for convenience into five divisions. In Nos. r to [0 he speaks of the anatomy and physiology of the genital orgms of the fowl, and the manner of production of eggs. Nos. 11 to 13. and also Nos. z_3 and 35 deal with the hen's egg in detail, describing -Lg parts and “W uses, while in Nos‘ 14. to 22 the process of the "generation of the foetus out of the hen egge” is described. The greater part of the book, com- prising Nos. 25 to 62, as well as Nos. 71 and 72, is theoretical, and treats of the ernbryological theories held by Aristotle on the one hand, and the physicians, following Galen, on the other, instead of which it pro- pounds new views upon the subject. Finally, Nos. 63 to 70, as well as the two appendices or “particular discourses,” are concerned with embryogenesis in viviparous animals, especially in hinds and does. And just as Aristotle put: much of his best embryological work into his Hixtaria Animalium and not into the work with the ap- propriate title, so Harvey has some admirable observations on the embryonic heart scattered through his D2 Illalu Cordi: et Sanguintlv in Animalibur.

It will be best to refer to some of the main points of interest in Harvey's discussions before trying to assess his principal contribu- tions to the science as a whole. Harvey is the first, since Aristotle, to refer to the “white yolk" of birds.

For between the yolk which is yet in the cluster and that which is in die midst of the eg when it is perfected this is the diflerence in chief, that though the former be yellowish in colour and in appearance, yet its consistence repre- senteth rather the white, and being sodden, thickeneth like it, growing com- pact and viscous and may be cut into slices. But the yolk of a perfect egge being boiled groweth friable and of a more earthy consistence, not thick and glutinous like the white.‘

All of Harvey’: observations on the formation of the egg in the ovi- duct contained in this chapter are interesting, and may with advantage be compared with the studies of Riddle and Asmundson upon the same subject, where the chemical explanation will be found for many of Har'vey’s simple observations.‘ Harvey's controversy with Fabricius on the question of whether the egg is produced with a hard shell or only acquires its external hardness upon standing in the air, which follows immediately on the above citation, is interesting.’

Fahricius seemeth to me to be in errour, for though I was never so good at slight of hand to surprise an egge in the very laying, and so make discovery whether it was soft or hard, yet this I confidently pronounce that the shell is compounded within the womb of a substance there at hand for the purpose, and that it is {tamed in the same manner u 13, the: pm, gf ‘h ‘'19 Piisfick faculty. Ind the rather, beause Ichgve seen an ueegedrgrigliemgfly egge uhsch had a shell of its own and yet was contained within another egge greater and fairer than it, which egge had a shell too. '

’ P. 47.

' A great tteoauty of intomution about the physioo-cheeniul nature and properties of the eggs of birds and all their constituents is rmw available in the book ofRorrm1o'v 5: Romanov. Nothing has yet replaced the author‘: systematic Chmital Embryology (193 I) though the wealth of new knowledge won about chemical changes during embryonic development during the put twenty-six year: make: this urgently necessary. l\‘i:llI,IWh1le Ilncheth ttirnuhung monograph will be found very helpful.

Harvey was the first to note that the white of the hen’s egg is hetero‘ geneous, in the sense that part of it is much more liquid than the rest, and that the more viscous part seems to be contained in an exceedingly fine membrane, so that if it is sliced across uith a knife, its contents will flow out._ He also set right the errors of Fabricius, Parisanus and others, by showing that the chalazae were neither the seed of the cock nor the material out of which the embryo was formed, and, most important of all, by demonstrating that the eicatricula was the point of origin of the embryo. He denied, as against popular belief, that the hen contributed anything to the developing egg but heat.‘

For certain it is that the chicken is constituted by an internal principle in the egge, and that there is no accession to a complete and perfect egge by the Hermes incubation, hut bare cherishing and protection; no more than the Hen contrihutcth to the chickens which are now hatched, which is only a friendly heat, and mre, by which she defendeth them from the cold, and

forreign injuries, and helpeth them to their meat.

Whether future work will still afiinn that nothing is given to the egg by the hen except heat is beginning now to be in do!-lbl. 151116 RSV-tits Of Chattock are correct.

In the description of the development of the embryo in the hen's egg. which remains to this day one of the most accurate. Harvey Says ' Wilh regard to the spot an the yolk, which had, of couficy 5061 S5911 and H16“- tioned by many previous observers, "And yet I C0flCCi\‘€ (hit 110 mm hitherto hath acknowledged that this Cicatricuiil W35 t0 ht found in every egg: nor that it was the first Principle of 111? Pfggm" Thus ii? unequivocally identified the hlastoderm (with its pnmrtiye streak and neural folds) as the unique place of origin of the €mbfY0fll“» b°dY-'_H“"_ description‘ of the beginning of the heart, that “rapenng bloody point or pxmcmm mliem, is too famous to need more than 3 !’ciCI€-n<_3€- H9 thought that the amniotic liquid was of “mighty "Sh" ‘T01’ “"51-[5 91¢ embryos swim there, they are guarded and skrecncd from =ii1.¢0I1€U-9' sion, contusion, and other outward injuries, and are 3150 11°“-\'15h¢d hi’


' P. 69. ' P» 33- . ‘The term itself, Xdmhau: (blastodern-A), is of course one of those mlroduced by

Pxnder in I817. I Pp. S9, 9: ' P. as.

Thus he made no advance on the opinion which had for long been held, namely that the amniotic liquid or colliquamenturn served for SLISCCXIBIICC.

I believe [he says] that this eolliquamenturn or water wherein the foetus swims doth serve for his sustenance and that the thinner and purer part of it, being imbibed by the umbilicall vessels does constitute and supply the primo- genital parts, and the rest, like Milk, being by suction conveyed into the stomack and there concocted or chylified, and afterwards attracted by the orifices of the Meseraick Veins doth nourish and enlarge the tender embryo.‘

His arguments for this are, (1) that swallowing movements take place, and (2) that the gut of the chicken is “stuft" with excrement which could hardly arise from any other source. He was thus led to divide the amniotic liquid into two quite imaginary constituents, a purer and “sincerer" part, which could be absorbed straight into the blood with- out chylification, and a creamless milky part, which could not be treated so simply.

About the fourth day [says Harvey] the egg beginneth to step from the life of a plant to that of an animal]! . . . From that to the tenth it enjoys a sensitive and moving soul as Animals do, and after that, it is compleated by degrees and being adorned with Plumes, Bill, Clawes and other furniture, it hastens to get out.’

These and other passages which deal with the forerunner of the theory of recapitulation are interesting, but we have already met essentially the same idea in Aristotle. Harvey contributed nothing new to it. The first point on which he went definitely wrong was the conviction he reached that the heart does not pulsate before the appearance of the blood. No doubt his lack of microscopical facilities or of the desire to use them affords the reason for this error, but it was a rather unfortunate one, for it was to a large extent upon it that he formulated his doctrine‘ "the life is in the blood." For example, he says, “I. am fully satisfied that the Blood hath a being before any part of the body besides, and is the elder brother to all other parts of the foetus."'

The yolk, Harvey thought, supplied the place of milk, "and is that which is last consumed, for the remainder of it (after the chicken is hatched and milks abroad with th H ' ‘ ' ' be“!-"‘ He thus mused himself “in; Alizi-«ce)cxl;sail:1t.:fxl:§::11:l:1iei;nilt1l his remarks about the relationships of yolk and white in nutrition are worth consideration; m noting, for instance, that the yolk is the 133: :0 be consumed, he comes very near to anticipating the modem conczption of a succession of energy-suuroes.

‘ P. 358. _ ‘ P. 89. ' P. ror.

‘ This doctrine was not peculiar to Harv (cf. Levit. xvii. r r and r4. Servetus, am). See aka the elaborate ltudy of Rilsche on a relation between blood, life and mu! in ancient thought.

1“ 913‘ Pl1Y§|Ui}“5 3551706. flu! the Yolk: is the hotter part of the egge, md the most nourishing, I conceive that they understand it, in relation to us, as it B become our nourishment, not as it doth supplymore oongruous alimem to the chicken in the egge. And this appear-es out ofourhistory ofthc Fabrick of the ohxcken; which doth first prey upon and devoure the thinner part of 316’ Wlmc. before the gmsser; as it were a more proper diet, and did more easily submit to transmutation into the substance of the foetus. And therefore the yolk: seems to be a remote: and more deferred entertainment than the Whit: for all the white is quite and clean spent, before any notable invasion is made upon the yolk.’

A comparison between these simple facts and our knowledge of embryonic nutrition is most interesting.

In connection with Minot's distinction of the periods of embryonic growth, it is curious that Harvey says,

And now the foetus moves and gently tumbles, and stretcheth out the neck though nothing of a brain be yet to be seen, but merely a bright miter shut up in a small bladder. And now it is a perfect Magot, differing only from those ltinde of wormes in this, that those when they have their freedom crawle up and down and search for their living abroad, but this worm constant to his station, and swimming in his own provision, draw! it in by his Umbilicall Vessels.‘

Sometima Harvey confesses himself puzzled by problems which could only be solved by chemical means, yet it does not occur to him that this is the case. For instance, he enquires why heat will develop a chick out of a good egg but will only make a bad one worse.

Give me leave to add something here [he writes] which I have tntd _0lf=1I3 that I might the better discerne the acituation of the foetus and the liquor: after the fourteenth day to the very exclusion; I hove boi.led_m egg: fill it grew hard, and then pilling may the shell and scclng the scntuatwn DY ‘hf! chicken, I found both the remaining pans of the white. and ‘hf N” P‘-“'5 °f the yolk of the same consistence, colour, tast, and other accidents: as my other stale cgge, thus ordered, is. And upon this Eltpenmenlu I ‘M mud‘ ponder whence it should oome to passe that lmprohfigl eggs should. ‘V01: the adventitious heat of a sitting Herme, putnfie md stn-ilr; and yct no inconvenience befall the Prolifical. But both these liquors (thoughlthere be a Chicken in them too, and he with some pollution and excrement) should be found wholesome and incorrupt; so that if you eat them in the dark after they are boyled, you cannot distinguish them from egges that are so prepared, which have never undergone the hen's incubation.

| P. ros. ' P. 183. ' l’- H1-

Harvey was never afraid of trying such tests on himself; in another place, for example, he says,

Eggs after 2 or 3 days incubation, are even then sweeter relished than stale ones are, as if the cherishing warmth of the hen did refresh and restore them to their primitive excellence and integrity.‘ . . . And the yollte (at 14 days) was as sweet and pleasant as that of a newlaid egge, when it is in like manner boyled to an induration!

Another matter on which Harvey set Fabrieius right was on the question whether at hatching the hen helps the chicken out or the chicken comes out by itself. The latter was the belief held by Harvey, who said of Fabricius’ arguments on this point that they were “pleasant and elegant, but not well bottomed.“

On the great question of preformation versus epigenesis, Harvey keenly argued in favour of the latter view.

There is no part of the future foetus actually in the egg, but yet all the parts of it are in it potentially.‘ . . . I have declared that one thing is made out of another two several wayes and that as well in artificial as natural productions, but especially in the generation of animals. The first is, when one thing is made out of another thing that is pre-existent, and thus a Bedstead is made out of Timber, and a Statue out of a Rock, where the whole matter of the future fabrick was existent and in being. before it was reduced into its subse~ quent shape, or any tittle of the designe begun. But the other way is when the matter is both made and receiveth its form at the same time.‘ . . . So likewise in the Generation of Animals, some are formed and transfigured out of matter already concocted and grown and all the parts are made and distinguished together per memmorphorin, by a metamorphosis, so that a complete animal is the result of that generation; but some again, having one part made before another, are afterwards nourished, augmented, and formed out of the same matter, that is, they have parts, whereof some are before, and some after, other, and at the same time, are both formed, and grow.’ . . . These we say are made per epigenerrh, by n post-generation, or after-production, that is to say, by degrees, part after part, and this is more pmperly called a Generation, than the former.‘ . . . The perfect animals, which have blood, are made by Epigenesis, or supenddition of parts, and do grow, and attain their just future or dx,u17 after they ttre born.’ . . . An animal produced by Epigenesis, attracts, prepares, conoocts, and applies, the Matter at the same time, and

‘ P. 126. ' P. 64. ' P. 65. ‘ P. X29. ‘ P. 21!. ' P. 221. ' P. :22. ' P. 222. ' P. 223.

is at the same time formed, and au cm x 5. . erroniously seelt after the Matter of 51!: chizilen (u'<i::ii§:p:i izilgtixefegug wlhiicclik went to the unbodymg of the chiien) as though the geueu.

c e an were effected by a Metamorphosis, or transflguration of sornelcollected lump or mass, and that all the parts of the body, at least the Pnnupsll parts, were wrought off at a heat or (as himself: speaks) did ads: and were oorporated out of the same Matter.’

Nothing could be more plain than Harvey's teaching an epigenesis.

On the relation between growth and difl'erentiau'on Harvey has some valuable things to say. The term "nutrition" he restricted to that which replaces existent structurs, and the term "augmentation" or "incre- ment“ to that which Contributes something new. That process which led to greater diversity of form and complexity of shape he called ‘‘formation‘‘ or “frarning."

For though the head of the Chicken, and the rest: of its Trunck or Cor- porature (being first of a similar constitution) do resemble a Mucus or soft glewey substance; out of which afterwards all the parts are framed in their order; yet by the same Opemtour they are together made and augmented, and as the substance rsembling glew doth grow, so are the parts distin- guished. Namely they are generated, altered, and formed at once, they are at once similar and dissimilar, and {rum a small similar is a great organ made.’

Harvey was thus very certain that the processes of growth in size and differentiation in shape went on quite concurrently, though he had no inkling of changes in the relative rapidity of each process. On this point he goes further than Fabricius. Fabricius thought that growth was a more or less mechanical process, taking its origin from the pro- perties of elementary substances, but that differentiation was brought about by some more spiritual or subtle activity.

Fahxicius [says Harvey] alfirmcs amisse, that the Imrnutative Faculty doth operate by the qualities of the elements, namely, Heat, Cold, Moisture, and D:-yncg (as being its instruments) but the Forrnmvf: Wofks Without them and after a more divine manner; as if (fersooth) she did fimsh l_'-ct task with Meditation, Choice, and Providence. Forhad he looked deeper unto the thing, he would have seen that the _Formatxve as well the Alteratw: Faculty makes use of Hot, Cold, Moist, and Dry, (as her rnstrumen!-9) 3“

would have deprehended as much divinifY “mi ‘km i" N“"ifi°n and ham“.

tation as in the operations of the Formative Faculty her self. . . . I 537 11*‘

Concoctmg and Imxnutatrve, the Nutntrve and Augmenung Faculties (“hf Fabricius would have to busre themselves only about 13:12, glgld. and Dry, without all knowledge) do QPCIIW Willi W“ 3“ °°'

much to a designed end, as the Formatxve faculty, which he aflinns to 9°95’

, P. 2“ . 3 us, - P. 308.

the knowledge and fore-sight of the future action and use of every particular part and organ.‘

Here Harvey adopts a more organic conception, being unwilling to regard growth as more mechanical than morphogenesis. “All things are full of deity (jovis onzm‘apIena),” said he,‘ "so also in the little edifice of a chicken, and all its actions and operations, Di;-flu: Der‘, the Finger of God, or the God of Nature, doth reveal himself."

There can be no doubt that Harvey’s leanings were vitalistic. In the following passage, he argues against both those who wished to deduce generation from properties of bodies (like Digby) and the Atomists (like Highmore). Aubrey notes that Harvey was “disdainfull of the chymists and undervalued them."

It is the usual error of philosophers of these times [says he] to seek the diversity of the causes of parts out of the diversity of the matter from whence they should be framed. So Physicians affirm, that the dilferent parts of the body are fashioned and nourished by the different materials of blood or seed; namely the softer parts, as the flesh, out of a thinner matter, and the more earthy parts as the bones, out of grosser and harder. But this error now too much received, we have oonfuted in another place. Nor are they lesse de- ceived who make all things out of Atoma, as Demoeritus, or out of the elements, as Empedocles. As if (forsooth) Generation were nothing in the world, but a meer separation, or Collection, or Order of things. I do not indeed deny that to the Production of one thing out of another, these fore- mentioned things are requisite, but Generation her self is a thing quite dis- tinct from them all. (I find: Aristotle in this opinion) and I my self intend to clear it anon, that out of the same White of the Egge (which all men confesse to be a similar body, and without diversity of parts) all and every the parts of the chicken whether they be Bones, Clnwes, Feathers, Flesh, or what ever else, are procreated and fed. Besides, they that argue thus assigning only a material cause, deducing the causes of Natural things from an involuntary or casual concurrence of the Elements, or from the several disposition or con- triving of Atomes; they doe not reach that which is chiefly ooncemed in the operations of nature, and in the Generation and Nutrition ofanirnals, namely the Divine Agent, and God of Nature, whose operations are guided with the highest Artifice, Providence, and Wisdome, and due all tend to some eertaine end, and are all produced, for some certaine good. But these men derogate from the Honour of the Divine Architect, who hath made the Shell of the Egg: with as much skill for the egge’s defence as any other particle, disposing the whole out of the same matter and by one and the same formative faculty.‘

But although these are Harvey’s theories, it is significant that in his preface he says, "Every inquisition is to be derived from its causes, and chiefly from the material and efficient," thus expressly excluding formal

‘P. 399. 'P.:Io. ‘E51.

and final considerations. Certainly, as far as his practical y.-mk mm 1,, gifntnmmed blélhem. and In case of the egg-shell, for example, C b Y 3333 I301}: e man to say. it is present for the protection Ofdlc “I1?! 170;] t en to do or say nothing more. Such an explanation,

vush c nuehg gladly accept u. was no bar to further exploration bath by way of expenment and observation.

Harvey not only follows Aristotle in his good discoveries and true statements about the egg, but also, unfommately, in his less useful parts, 33. T01’ exam_ple,'when he devotes several pages to the discussion ofhow fa’ ‘bf’ 989’ 13 ‘NW3. and whether there is any soul in suhventaneous or unfrurtful eggs. He decides that there is only a vegetative soul. On the other hand, he admimhly refutes the opinion of those physicians—who were not few in number‘-who declared that the foetal organs were all functionless during foetal life.

But while they contende that the mother’s Blood is the nutriment of the foetus in the womb, especially of the Porter Sangufnzae, the bloody parts (as they mll them) and that the Foetus is at first, as ifit were : part of the mother, sustained by her blood and quickened by her spirits, in so much that the heart beats not and the liver sanguifies not, nor any part of the Foetus doth uecute any puhliek function, but all of them make Holy-Dsy and lie idle; in this Experience itself confutes them. For the chicken in the egge enjoycs his own Blood, which is bred of the liquors contained within the egge, and his Heart hath its motion from the very beginning, and he borrow- eth nothing, either blood or spirits from the Hen, towards the constitution either of the sanguineous parts or plumes, as those that strictly observe it may plainly perceive.‘ We have already seen how the Stoirs in antiquity believed that the embryo was a part of the mother until it was born; from tnis idea the transition would be easy to the belief that all the organs in the embryo were functionless and dependent on the activity of the corresponding ones in the maternal organism.‘

One of Harvey's most important services to thought lay in his abolish- ing for good the controversy which had gone on ever since the srsth century 13.0. about which part of the egg was for nutrition and Wl'1lCl'l for formation. He had the sense to see that the distinction was a uselss and baseless one

There is no distinct part (as we have often said) or disposed nutter out of which the Foetus may be formed and fashioned. . . . An egg}: is that thing, whose liquors do serve both for the Matter and the Nourishment of the foetus. . . . Both liquors are the notmshrnent of the foetus.‘

i h'ti.73‘p2.,sic;uu ma also refuted on. state tutigz, so Daniel Winekltr in 1630.

‘ P. 210.

As regards spontaneous generation, Harvey considered that even the most imperfect and lowest animals mule out of eggs.

We shall show that many Animals themselves, especially insects, do germi- nate and spring from seeds and principles not to be discerned even by the eye, by reason of their contract invisible dimensions (like those Atornes, that fly in the sire) which are scattered and dispersed up and down by the winds; all which are esteemed to be Spontaneous issues, or born of Putrefaction, because their seed is not anywhere seen.‘

Unfortunately, he never did return to this subject, for, as he himself informs us in another place, all the papers and notes in his house in London were destroyed at the time of the Civil War, so that what he had written on the generation of insects irretrievably perished.‘

Another point on which Fabricius had been in error was the appear- ance of bone and cartilage in the embryo. According to him, “Nature first stretcheth out the Chine Bone, with the ribbes drawn round it, as the Keel, and congruous principle, whereon she foundeth and finisheth the whole pile." This armchair conceit Harvey was easily able to destroy by a mere appeal to experience, but by experience also he came upon a fact less easy to be explained, namely that the motion of the foetus began when as yet there was hardly any nervous system. “Nor is it less new and unheard of, that there should be sense and motion in the foetus, before his brain is made; for the Foetus moves, contracts, and extends himself, when there is nothing yet appears for a braine, but clear water.”‘ On the basis of this paradox Harvey may be said to be the discoverer of myogenic contraction, but he could already claim that distinction, for the first heart-beats are accomplished long before there are any nerves to the heart, as he himself points out. "We may conclude from this fact," he remarks,‘ “that the heart and not the brain is the first principle of embryonic life,” and he gives instances of physiological actions not under the conscious control of the individual, such as the reflexes, as we should call them, of the intestinal tract, and the emetic action of infusion of antimony which cannot be tasted much and "yet there passcth a censure upon it by the Stamack”' and a vomit ensues. Thus, twenty-five years before Francis Glisson, Harvey bad formu- lated, from embryological studies, the View that irritability was an intrinsic property of living tissues.

‘ P. 205.

‘ There is some obsuzrity in Harvey's Ittirude on spontaneous genention, as Red‘: pointed out in 1663, for if the "seed!" from which insects original: are not always

neoestarily derived from previous insect: or the name species, they do not ditfer so

greutly_fx-um the Sxoie-Knbbalutic "seeds" (nee pp. 66 and 80 pasaim), and hence nhnde into Epicurean Items.

' P. am. 4 P. 345. ' P. 348. ‘ P. 349. 143

Both Harvey and I-‘abricius were very puzzled about the first origin of the hlood. What artrficer,” says Harvey,‘ "an mmfom an “,9 liquors rnto blood, when there is yet no liver in being?" It was to be a long time before this question was ariswered by Waltl"s disomtry of the blond islands in the blastoderm, and, even now, the chemistry of the appar-ance of haemoglobin is one of the most obscure problems of chemical embryology. The older observers explained it by considering the yolk to be akin to blood and ready to turn into it at the slightest inducement.

Another problem which neither Fahricius nor Harvey did anything to solve was the nature of the air-space at the blunt end of the egg.

Fahrieiu: recounts several amveniences arising from it. acoordirtg to it: several magnitudes, which I shall declare in short. flying. It contains aire in it. and is therefore commodious to the Ventilation of the ego, to the Respira- tion, Transpiration, and Refrigeration, and lastly to the Voeiferation of the Chicken. Whemxpon, that cavity is at the Era: verylinle. after-wank greater, and at last greatest of all, acoording as the several recited uses do require.‘

As regards the placenta, Harvey took the side ofAraru:ius and denied any connection between the maternal and foetal circulations.

The atremities of the umbilical] vessels are no way mnjoined to the ex- tremitiu of the Uterine vessels by an Anastomnsis, nor do extract blood from them, but are terminated in that white rnueilzginous matter, and are qunte obliterated in it, attracting nourishment from it.‘ . . . Wherefore these rar- uncles may be justly stiled the Uterine Cakes or Dugs. that is to say, tarm- venient and proportionate organs or instruments duaigfltd 701‘ 15¢ Wnmnmfi of that Aibuginou: Aliment and for preparing it for the attraction of the

veins.‘ He criticises van Spieghel for not going farerlflllgh l-n‘l'i3-

There came forth a book of late, wrote one Ad1_'l1nII5 Spigrlins. W153‘;-'1 he treateth concerning the use of the umhilrmll arteneS_Im‘l by power-full arguments that the Foetua doth not receive its Vital Sprnn by the arteries from the Mother, and hath fully answtfld 1509: WWW” which are ulledged to the contrary. But he might also as you have rm“ '0’ the same arguments that the blood neither is transpottnd IN-_° lllfl 5"? the mother’: vcincs hythe propagation: of the umhrillcallvuns, E calsmi C chiefly manifest by the examples drawn from the H¢I|-EE8° “"1 9 “'33”

Birth.‘ From all this it would appear that Han’¢7Y nfiudfid ‘he “win.” milk” the special secretion of the plaoenta. €<_!11V_=)'¢d ‘U “"5 f°"_“’ umbilical cord. The nature and constitution of the uterine 13

very imperfectly understood. Its discovery is usually attributed to Walter Needham, but various remarks in this chapter (Ex. No. 7o) seem to show that Harvey was well acquainted with it. In later times it was regarded by some (Bohnius and Charleton in 1686, Zacehias in 1688 and Franc in 1722) as the sole source of foetal nourishment. Merclrlin spoke of it in 1679 as malaria albuginm, orig:/e 1115!) mm ab.rz'mz'Iz'.

The least satisfactory parts of Harvey's book are Exercitations Nos. 71 and 72 on the innate heat and the primigenial moisture. Here he becomes very wordy and speculative, giving us little but confused and puzzled argument. He devotes many pages to proving that the innate heat is the blood and to drawing distinctions between blood and gore, the one in the body, the other shed.‘ In one place he speaks of the processes of generation as so divine and admirable as to be “beyond the comprehension and grasp of our thoughts or understanding.” Two centuries previously Frascatorius had said precisely the same thing about the motion of the heart, and it was ironical that the very man who shed a flood of light on cardiac physiology should in his turn have des- paired of the future of our knowledge of embryonic development.

Harvey did not say much about foetal respiration, and his few remarks are contained in one of the “additional discourses.” He was puzzled exceedingly by the question. But he came very near indeed to the truth when he said,

Whosoever doth carefully consider these things and look narrowly into the nature of sire, will (I suppose) easily grant, that the Aire is allowed to ani- mals, neither for refrigeration, nor nutrition sake. For it is a tryed thing, that the Foetus is sooner sufiocated after he hath enjoyed the Airs, than when he was quite excluded from it, as if the heat within him, were rather inflamed than quenched by the sire.‘

Had Harvey pursued this line of thought, and looked still more narrowly into the nature of air, he might have anticipated Mayow. He does say that he proposes to treat of the subject again, but he never did.

5. The Riddle of Fertilisation

The rnainspring of Harvey's researches on the does and hinds can be understood by a reference to Ruett"s figures in Fig. 10. According to the Aristotelian theory, the uterus after fertile copulation would be full of menstrual blood and semen; according to the Epicurean theory (held

' Here Harvey was standing at the boundary beyond which no one could go yvithout chemical thought and experiment. “Innate hear" and "primigenml momure. ’ mid: term: though they were, recognised phr.-no-rnem which we now know to be those of thnr concert at enzyme Ictions constituting rnzubolum, and the complex of factors

pgevent the dennruntion of protein molecule: in the living body. by the "physitlans") it would be full of the mix d einni' I '

. , . I agulatcd mass exists, said Harvey, it ought to beepogsiblento dissection, and this “'43 what he tried to do.‘ It soon became plain an my be read in Ex. No. 68, not only to Harvey but to the, King and :5: K1118 9 8“m°l‘°°P°’S, that no such coaguluin existed. and the result was made still more certain by means of segregation expcfimgnts w1,,'¢h (he Km? °a“l'd °“‘ 3‘ Hamlnfln Court.’ Accordingly there was nothing to be done but to abandon all the older theories completely, and have fewuise to some sort of hypothesis in which an aim: semi'ria!i's, an

incorporeal agent" or a "kind: of contagious property" should bring about fertilisation. This was it perfectly sound deduction from Harvey‘; expei-iments, and did not then appear anything like so unsatisfactory as it does now, for Qilben oticolchester was not long dead, the "lode- stone was beginning to be investigated by the virtuosi} and even sud: extmvagtinces as Sir Gilbert Talbot’s Powder “for the sympatheticall cure of wounds" were only with difiiculty distinguishalzile from the real

effects of magnetic force.‘ But to Harvey himself the subject of the action of the seed was hid

in deep night, and he confessed that, when he came to it, he was “at a stand." Some very interesting light is thrown upon his mind in this connection by a copy of the De Generation: Am'malx‘mri annotated by

himself, and now in the possession of Dr Pybus, by whose courtesy and hythnt of Dr Singer, who has transcribed the notes, I hat :2 been enabled

1 See pp. mg, 258, 25!. 4:6.

‘ The amount given by Harvey himself (r653. PA 4x6) emnoi be omitted: “When I had often discovered to His hlnjtslirs sight lhll lltention in the Womb, Ind hmng likewise plainly shewed that all this vihile no portion of seed oraonoeptian either an to be found in the Womb, xnd when the King hit-riself hxd coinmtiniuted the nine :3 I very wonderful thing to diverse of his followers, 1 great debut: at length Iruse: ’I_‘he Keepers and fluntunm concluded, tint, that this did imply, um their cnnczptzan would be late that year, I_nd thereupon accused the drought; but afttrwgrds when they understood that the time was past and gone; and thn I stood gnfliy upon that. they pegzmptanly did noami, um I ms rim rriutalten my lelfe, and so had dnvm the King into my error: And that it could not possibly be. but [hit iomzihing It lest of the Conception must needs lppeu in the Uierui:_ui-iull I! last, being cnnfuttd by their own eyes, they sat: down in a gaze Ind guveit over [or gnnted. But all the Kings Phyiitiam persisted may that it could no waits be, out . oonczptmn Should go for- wud unless the males seed did remain in the womb. ind that there should be noLhin£ .¢ .11 “siding in die Uterus Ifter : t‘ruitt‘u1l md efieeruall Ceitimi; [1111 they mated amongst their ’ndi}rarix.

"Now um um experiment which is of no great concern might Ippear the ninrc evident to posterity; I-li_x Majestic for nynaate (because they hnve in the um: um: and mama o( em-ieepuori) did at the beginning of October separate nbout a damn Does from the society of ih_: Bud: u-id lock them up In the Course n_eer Hampton Court. New lest iiny_one l_n_ighl lfl"£nI1‘lh2f doubtlessly_theze did continue the see: bestowed upon them in Coitinn (their time of “I11!-1l?g being then not put) X dissect: diverse of them, Ind discovered iio seed it ._u midmg in their Uterus; Ind yet then

did conceive by the virtue of their former Ccition (A: by Con-

vihom 1 dixsected not. _ , _ ,, tagiori) Ind did Fuwn at their lppolnted time.

Fig. 2.1. Illanmrripl mun of Dr. William Harvey.

to study it. It was given by Harvey to his brother Eliab, whose name it still bezus. The notes, which are on the fly-leaves, are written in much the same way as those famous ones which Harvey used for his lectures at the College of Physicians in London, and which have been repro- duced in facsimile. There is the same mixture of Latin and English, and the some signs, such as WI, to denote thoughts claimed as original. A page is reproduced in Fig. 14.

For the most part, the notes are uninteresting and nothing but a confusion of Aristotelian terms, yet one page is concerned with the mode of action of the seed, and here we can, as it were, sce Harvey's mind wrestling with this most difficult of problems. He thinks that

Odour and the sense of smell maygivc a clue.‘ That his thoughts on this patnt were doomed to oblivion as soon as egg-cells and spermatozoa were discovered does not detract from the intermt of his struggle

Quod tacit semen fecundutn another . . . and by the name . . . Jag? woman in whose uterus is the poison.

They do not [or do not yeti] come forth in actuality but lie dormant as in warm fcnnentiog matter [P fomite]. Again, rabies in dog, 1,53 damn, {M many days on my own observation VW. Again, smallpox for days. Again_ the Hellcrative need, just as it (passes) from the male, lis dormant in the woman as In warm fermenting matter (2).

Or else like a . . ., like light in stone . . ., the pupil in the eye, in sense motion, . . . in the body.

Like ferment, vapour, odour, zottennm . . . by rule.

0: like the smell given off by flowers.

Like heat, inflammation (2) A in lime (heat?) bath the wet form. . . .

Like what is first . . . in the art of waking . . . principles ofvcgetatian and propagation. A Dormioe by hibernating . . . cleansing by mtg; and :11 kind, of lotions, apin for insects, as for their seeds as well (P) Or when a soul is a god present in nature, that is divine which it brings about without an orpnic body by means of law. See Ankmk Marvel? concerning odours and smells given 01?. Whether an mm .55 everythmg that an be smelt give: ofl’ something and so 13“ °bi¢m of disperses (3) what is not without hat, or by destroying. . . ""‘°‘ attracts to itself.

A Amongst inflammable (objects are) lire, naphtha, paper. . . .

A V\Hmanusetodoremr...anatomiamanair....

A Amt . . . post 4°‘ paras. otium indinente die rursua quad prius et

olen-ere vid. .2 . Galen. . . .

A Mr. Boy: apainel in Paris lay all ye third night and morning in getting dogg. Whelping dogg’s sent (scent) are a stronger sent, vesting in vestigio alios ord . . . gr . . . lepxis odore lepris me hbidine esse. Hots, the mare, hurt, the cow, a bull per mutta rnillsa.

A...ei lepra {raoedo in farioli fade: cupidinitua. Dogg ye otter in aqua:

fracedo vasorum ex aulpore?

Such were the thoughts on action at a distance, on particles, odorous or contagious. flying from place to place, on fermentation and latency,

‘ And that there may be some analogy between lenilrsnuon and the transmission of an infectiotn disease. On this pain: John Nlrdt of Florence, one o_l' Haney’: corre- rpondentgfheld tcllale urnefopxnmn, uhthe legten betwéegn Lgem,

‘ ‘ nu-v , . , to, I . ac themdohneuunfl =y.svw(I47 pp PésmAw§md ‘he

Gnlialcr (B logna. 655) contains - reference to the _ ‘ . enetr-ntion ‘hf egg-cilia by upennatowa and other cells by invasive butena was rally

inane iuofi the:-nxrk_

which thronged to I-larvey’s mind as he wrestled with the problem of fertilisation unaided by that triumphant tool the microscope.

6. Harvey's Achievements and Influence

Summarising now Harvey's influence on embryology, we must admit that it was in certain respects reactionary.

1. He did not break with Aristotelianism, as a few of his predecessors had already done, but on the contrary lent his authority to a mori- bund outlook which involved the laborious treatment of unprofitable questions.

2. His dislike of atomism and "chymistry” precluded any close co-operation between his followers and those of the Descartes-Gassendi tradition.

But these failings are far outweighed by his positive services.‘ It must again be remembered that he used no compound microscope, and was content to rely, like Riolan, on “perspectives,” or simple lenses of very low power.

1. There can be no doubt that the doctrine omne vivum ex ova was an advance on all preceding thought. Harvey's scepticism about sponta- neous generation nntedated by nearly twenty years the experiments of Redi.‘ It is important to note that he was led to his idea of the mamma- lian ovum by observations on small embryos surrounded by their chorion no bigger than hen's eggs, for the follicle was not discovered until the time of Stensen and de Graaf, and the true ovum not till the time of von Baer.'

2. Extending this doctrine downwards as well as upwards, he denied the possi lity of generation from excrement and from mud, saying that even verrniparous animals had eggs.

3. He identified definitely and finally the cicatricula on the yolk membrane as the spot from which the embryo originated.

‘ Attention is drawn by Bilflriewia (P- is) to the peculiarly empirical tradition of English philosophy described Lg. by \, Ind Hlrvty is placed in I line of dueent tnoorpomtlng Roger Bacon. Duns Scotus, William of Occltm and Francis Bacon. On Harvey‘: knowledge of his predecessors. see Fraser-Harris.

' The cnlehll words in Redi': Generation of buem ought not to be omitted: "I began to believe um nu worn-it found in mm! were derived directly (mm the the ping: of flier, and not from putrefaction, Ind I was Itill more confirmed in this be rat by having observed that before the meat grew worrny flies had hovered over it, of the I-me kind that later bred in it. But belief would be vain without the confin-nnu'on of experiment, hence in the middle of July I placed I snake, lamb fish, some eels of the Arno, and I slice of milk-fed veal In four large, wide-mouthed flaslu; having well closed and ruled than, I then filled the some number of other tlnslu in the am: way. only leaving these open. It was not long before the meat end the fish, in these ucxmd vessels, became wormy, Ind tliu were seen entering Ind leaving at will; but in the closed flasks I did not see I worm, though rnuly day: had passed line: the dud llesh hid been put in them "

' See Suton Ind Come .

‘_i' Dl5°“55l"E ‘he question of metamo hosis re '


In addition to these achievements, th noticed mime, but equally important, are an mhm’ Pumps 1°”

5. He destroyed once and for all the Aristotelian (semen-blood) and Epicurean (semen-semen) theories of early embryogeny_ 111;; was perhaps the grates: blow he gave to the Peripatetic teaching on development. In spite of it, Sennertus, van Lind: and Sylvius adhered to the ancicnt views. and Cyprianus in 1700 had the distinction ofheing the last to support them in a scientific discussion, though Sterne in Trirtmm Shandy,‘ as late as 1759, referred to them in a way that shows they still lived on in popular thought.’

6. He handled the question of growth and difierentiation better than any before, anticipating the ideas of the present century. '

7. He settled for good the controversy which had lasted for 2200 years as to which part of the egg was nutritive and whichwas formative. by demonstrating the unreality of the distinction.

8. He set his predecessors right on a large number of detailed points, such as the nature of the placenta.

9. He made a great step forward in his theory of foetal respiration, though here he did not consolidate the gain.

0. He affirmed that embryonic organs were active, and that the ‘embryo did not depend on external aid for its principal physiological


But all these titles to remembrance, great as they are. do not account for the peculiar fascination of Harvey. A little of it is perhaps due to his imaginative style, which comes out clearly in Martin LI:-wellyn’s English version.’ A word of censure is due to Willis for transrnuting it in his translation into the dull and pedestrian style of X847. No one who reads the 1653 edition of Harvey can ever forget such metaphors as this, "For the trunclr. of the body hitherto resembles a skifl’ without a deck, being in no way covered up by the anteriour parts,” or the vigour of diction which promotes such remarks as, "In a hen~egge after the tenth day, the heart admits no spectators without dissection,“ or again,

'Bookr, Verbally, it was still quite possible to support the Hellenistic VIEW that the em-

bryo was formed from menstrual blood. in the postvhlnrveinn period. if it were nd~ mitttd that this blood flawed little by_lmle through the urnlnliul vessels. This on the position of John Frdnd in his treatise on meun-moon, Emmntologm (I700-I730).

5:31 i<7e§'nu point: out. there is no proof on: Llewellyn an the translator. Whoever n was deserves the Ipplause of posterity. ‘ P- 331- ‘ P- 331-

"For while the foetus is yet feeble, Nature hath provided it milder diet and solider meats for its stronger capacity, and when it is now hearty enough, and can away with courser cates, it is served with commons answerable to it. And hereupon I conceive that perfect eggs are not onely party-coloured, but also furnished with a double white,"‘ or, lastly, “An egge is, as it were, an exposed womb; wherein there is a substance concluded, as the Representative and Substitute or Vicar of the breasts.”'

In this connection, it would he a pity not to quote from the verses which Llewellyn prefixed to his translation of Harvey's book.’ After describing the controversies that followed the De Motu Cardir, he wrote

A Calrner Welcome this choice Peice befall,

Which from fresh Extract hath deduoed all,

And for Belief, bids it no longer hegg

That Castor once and Pollux were an Egge;

That both the Ben and Housewife are so mateht, That her Son born, is only her Son hatcht;

That when her Teeming hopes have prosp'rous hin, Yet to conceive, is but to lay, within.

Experiment, and Truth both talre thy part:

If thou canst ‘scape the Womenl there's the Art.

Live Modern Wonder, and be read alone,

Thye Brain hath Issue, though thy Loins have none. Let fraile Succession he the Vulgar Care;

Great Generation’s Selfe is now thy Heire.

Curiously enough, the “calmer welcome” which Martin Llewellyn hoped for actually happened. Harvey’s book was so well reasoned and

‘P. 391. _ ‘P. ;69. ’ One of Harvey’: epitaph: is of rntere.-it to the embryologut. It was In mscnptron, in n stmngc Latin lryle, attached to his statue in the Royal College of Physicians, Ind It perished with the building in the fire of r666.

Gulizlmo Hxrvea viro manumenth mi: immoruli hoe msuper

Coll:-gium Meclicorum Londiniemium Qui enim Sxnguini morurn Ur ex mixmhbus urrurn dedit meruix esse \ Smor per-peruus

—pn.-sumnhly "he who gave motion to the blood, even as he allotted to animals their

origin. has dcsencd to stand here for ever as their tutelary deity.” Aninteresring recent _

Iccount of Harvey‘: tar: ma tune: is ma: 0! Heringhun. Since the man account of Harvey’: work on er-nbryology was written, A. w. Meyer’: valuable Analyri: 0/ the D: Generation: Animabum 0/ Harvey hn Ippcared.

basedon such good observations that it produced only three answers, and

they were of little importance. Janus Orcharn took exceptionto Harvey’: finding no seed in the uterus and suggested that it had vapor-ised like a steam but his Aristotelian leanings were promptly detected and casti- gated ’by Rallius. Matthew Slade, taking the pseudonym of Theodore Aldcs, published in r 667 his Diuertatio epislolim tantra D. G. Harreium, which was, in his own words, "a detection of one_or trro errors in that golden bool: on the generation $2 animals of Willi.-ml: Han'ey,.:']e‘atesdt f h 'sicians and anatamists." e errors were pure y anatomr an

v;,PA,l,gg1ig dgfgnded Haney against Sladejs attack, claiming that the “gangs” war: not emns at all. A manuscript work of Slades appmrs b It! t. to Dfufingxihe first printing of this book there mine to my notice the attack of Alexander Ross on Harvey’s De Generation. As described on p. 127 Ross also wrote a polemic against Dighy (the Plu'Ia.ropIn'azIl gh; , 8 , d th following title shows the breadth of his 3hji1::ctizlJi’1’smt<:ccarI:)y:d!v)ar:aered thcought: Amzna I|Iim;amm'; or, the lid gene}; of man’: baafy discerned; in an nnatmnknl duel between An}laiIe Md G51," ,,,,,¢m,;,,g 3],; parts thereof; . . . mt}: a refulanon of Dr Bmtm», Vulgar Emrrr, (Ire Lam‘ Baton’: Natural Hixlary, and DI H 3. book D, Gmenztiane, Comerziur, am! atlrerr; rvlterelo 1': annexed a Zgrfim D,_ p,_ 19 1],; Aullmv and hit amwer thereto, touching Dr Hang’: book De Generations; by A. R. (Newwmb. II°“d°“-. 1:52)- This book upholds the Aristotelian them’? Of =fl1b5'°8“'5‘5 Tm trual bl d . 28 and the doctrme of spontantioufi generation a:_m;s55); it alas: aitlircks )Harvey's speculations on femlisat1on.(p._232). On p. :30 there is a passage which ma)’ 5931' 3 P'°f°m‘3,“°m5’ ’m“' “man. "The egg: is not altogether a body inorgammll act-tmllyu fereeing it hath different parts." The letter from Dr. Pr. is thus intro- , 4 ‘ ht ‘th this learned letter which

yhzsvteflalilifiexezito this Appendix, 111,3‘ 31°“

mflyst lmow how otiensiphea D§‘ll'larve.y’sut1>:pg1Tr:(;: 1;t:I:;Il1;r5W8e5r°: to myself.” It appears t EWCYS _ . . be th2nandW==!°°"‘“ %’?‘;:::°': the title Illediatr Medxmtur; or. I 2 {arm _ 3' _ Ienilive at gentle Potion.‘ Wm‘ 5”" ‘”’"""d""‘"°m "pm 5” Kmdm D1.”-‘.3 0b,m.,,,,-W, 0,. R,z,;g,'a2m.1;a', byll. R. (Young. Landon. 164;)- , . - 1 dil f lt b his cuntempornnes- tr-auss soon _ _ , h bl; _ him. gm [he has: mstance IS that in r65"5, very: soon after t e pu h 6;‘ . b k W,11;_,,,, Langly anezmnemscnatorandp :1 tron of Harvey's 53,0 . ' gamma mm: dfldupmem cian ofDordrecl1f, mad’ 3 BTW‘ “my ex?

of the hen's egg. Buffon says that he worked in 1635: ie. before Harvey, but this is not the case, for in his observations which were published by Julius Schrader in 1674 the later date is given several times. Langly mentions Harvey more than once, and evidently followed his example in careful observation, for his text is concise and accurate and his draw- ings very noteworthy (see Fig. 15).

Iulius Schrader included Langly’s work in a composite volume con- taining a well-arranged epitome of Harvey's book on generation and some observations of his own on the hen’s egg. The book was dedicated to Matthew Slade and I. Swammerdam. On the practical side Schrader added nothing memorable to Harvey and Langly, but it is noteworthy that the mammalian. embryo was throughout these centuries more popular material than that of the chick. Out of fifty emhryologists between Harvey and Haller, the names of Langly, Schrader, Malpighi, Maitre-Jan and Snape practically exhaust the list of those who studied the egg of the hen. This orientation of mind doubtless sprang from the strong influence of medicine, and especially obstetrics, on seventeenth- and eighteenth-century embryology.

One of the most interesting English followers of Harvey was Andrew Snape, farrier to Charles II, who in 1683 published as an appendix to his treatise on the anatomy of the horse an excellent account of the de- velopment of the chick and the rabbit. Often naming Harvey in the text, he accepts the doctrine of ex ova omnia, and of course identifies the whole hlastocyst with the mammalian egg, as Harvey had done. Follow- ing Highmate, he first describes the germination of plant seeds. His plate of the generation of the rabbit is copied without acknowledgment from de Graaf.

Snape is perhaps of interest as illustrating the influence of animal breeding on embryology. Just as the needs of practical obstetrics called forth the compilations of Bauhin and Spach in the sixteenth century, so after the destruction of the feudal economy in the English civil war, the needs of stockraisers stimulate Snape.‘

7. Atomist Theories of Embryonic Development; Gassendi and Descartes

'Harvey’s death took place in 1657. The following year saw the

publication of Pierre Gassendi's Opera Omnia, and thus brought in an entirely new phase in embryology.‘ Together with Rene Descartes‘

‘ For Si-nape‘: rather dubious position it: the history of comparative anatomy. see F. Smith. vol. I. p. 334. _ _

‘ The irnportlnt treatise of hhrcus l\‘l:rci, whoa: significance was fint Nllflfid by W. Plgel, might have been discussed here. but Iince that somewhat win: thinker stands in close relation to the Kabbzluh, he has been treated at an pp. 0-1. 11:.- was mueh more modern in his view: than either Gusendn or Descartes.

Isa The obmwzxjm nf rvumm gangry, made In 1655, w_ev: pub- In-hrd by 1. Schmdzr nl 1674, pnhap: yxmulafed by tin work of Illalpnght, ulna u n/epgd m in ma ggefnce. Th: frnnlirpnefz thaw:

mi: and an .;1m nnxing _/ram

em, and aim :1 ml 0/magmffing gins: av pempxculium, but mm u

no mmlmn uf it: we in La 1 ‘r Ierx. LangIy':_figurn, one 1 '.'f;.§2;. 1': IIPM up: of inmm m that they renmblz the picturu wluth mu 2! [mm been n_rezInI for Ilnmry‘: bank had xl barn ullumaud.

_,{,..z,4l.. nwf.72,

.4 Franmp' .. mg. :5. From 1. Srlundafx

E. Fig. III.

“Obnrvnlmnel ct Hlunrine, etc.," Anulevdam. I674.

treatise on the formation of the foetus, Gassendi's De generation: animalium et de mzimatianefoetu: marks a quite difierent attitude to the subject.‘ Harvey had adopted a rather contemptuous position about the “corpuscularian or mechanical philosophy," which was then coming in, and had expected even less help from it in the solution of his problems than from his equally despised “chymists." Gassendi now set out to show that the formation of the foetus could be explained on an atomist basis: and, using the Galenic physiology and the new anatomy as a framework, he set forth his theory in full. As we read it through at the present day, however, we cannot avoid the conclusion that it was not a success. In spite of his frequent quotations from Lucretius and his persuasive style, it does not carry conviction. The truth of the matter was that the time was not ripe for so great a simplification. The facts were insufliciently known, and that Gassendi is not quite as interested in them as he is in his theory is shown by the circurnstance that he only mentions Harvey once.

Gassendi examines in turn the Aristotelian and the Epicurean doc- trines of embryogeny and rejects them both, the former on the ground that the change from egg to hen is too great and diflicult for anything so shadowy and ghostlike as a “forrn” to accomplish, andthe latter because it leaves no room forteleology. He therefore adopts as the basis of hissystem atomism and panspennic preformationism, alleging that the germs of all living things were made at the Creation, but that they come to their perfection as atomic congregations in an atomistic universe. Thomas‘ monograph is a valuable help to the study of thisveryintercstingthinker.

At exactly the same time, Descartes was speculating on the same subject. Added to his posthumous De Homine Liber (1662) is a treatise on the formation of the foetus. He may also have written a work On the generation of animals, for a manuscript with that title was found among his papers after his death, and was believed to be in his handwriting. There is evidence, however, that it is not his, and though it was pub- lished in Cousin‘s edition of his works, we may safely neglect it, agree- ing, in the words of that editor, that it is “a fragment in which very mediocre and often quitefalseideasstruggle to light through rhemedium of a style devoid alike of clarity and grandeur." It must he admitted, however, that even his main treatise is very confused. It suffers from the fact that its earlier part contains much which really belongs to the physiological text-book immediately preceding it. Thus it begins abruptly in the middle of a disquisition on the error of attributing bodily functions to the soul. Before long, however, it warms to its theme, and a conception of growth is outlined.

‘ Opera, vol. :, Seer. ru, Bk. rv. pp. 2/6e ft.

When one is young, the movement of the little threads hid:

!’°_dY 5-‘ 15! 810w than it is in old age, because the thrndivare nifioporiziiii; J°"'‘'d 0'" I0 the other. and the streams in which the solid particles run are I-"B9: 50 that the threads become attached to more matter at their roots than f"“‘°."“ me“ f“"‘_' "*5" ‘3“'°““'-‘C3. so that they grow longer and thicker, in this way producing gm“-1h_1

I'he fourth part of the book is mlled, strangely enough, a Digression, in which the formation of the animal is outlined. The mixture of seeds is then described, and :1 theory of the formation of the heart attempted by n_"°““5 °f 3" 3"-'11°EY_“'1th ferrnentation. The arplanation is uncon- "f“°1“S- but has a oertaut interest as showing chemiul notions begin- ning to perrnute biological thought. Indeed, Descartes’ way of look- ing at. development was thoroughly novel, as is illustrated by the following citation.

How the heart to move. . . . Then, because the little parts thus dilated tend to continue their movement in .1 straight line, and because the heart now formed resists them, they move away from it and take their course towards the place where afterwards the base of the brain will be formed. They enter into the place of those that were there before, which for their part move in 3 drcular manner to the heart, and there, after waiting for a moment to snemble themselves, they dilute and follow the same road as the afore-mentioned ones, etc.

Destztrtes, in fact. with premature simplification, was trying to erect an embryology mare geometrica denwnrlrara,‘ That he failed in the attempt was as obvious to his contemporaries as it is to us—“We see," said Garden, "how wrctchedly Descartes came 05 when he began to apply the laws of motion to the forming of an animal." In doing so, he was many ymrs before his time.

But in the history of embryology these men and their writings have a very great significance.‘ Impressed by the unity of the world of phenomena, they wished to derive embryology as well as physics from fundamental laws This attempt, which resulted in a Galen-Epicurus synthesis on the one hand and a Galen-Desmrtes synthesis on the other, must be regarded as a noble failure. Its authors did not realise

‘Time’: mutations have I trick of justifying speculation: of I rnatenalnt clxaneter in my: unupeercd not only to lhur origlnll xuthnrs, but In men of gentnmms Just preceding our own. Here, for _example, Descartes‘ lxnaguutxre longing: sound: more mteresung m r957 than it did or x927, {or the mm-vemng year} have brought so much new knowledge of the fibrillar chuaeter of runny protein par-uela and molecules, not last those of embryonic cells. _ _

‘He would have been fascinated indeed by the great trennse of d grey Thompson (r9r7) eubmitting embryonic, _u an other, Me. to ngomps rmthemaucal n’catment- Io Cmesun. yet It the some urn: free tmmgll preeonoelved theory.

' See Heussler, de St Germain Ind Btflhltf.

what avast array of facts would have to be discovered before a mechan- ical theory could with any justice be applied to explain them. Gassendi and Descartes were like the Ionian nature-philosophers, propounding general laws before particular instances were accurately known. Their ineffectiveness arises from the fact that they did not themselves appre- date this, and consequently worked out their ideas in prolix detail, the whole of which was inevitably doomed to the scrap-heap from the very beginning. But the spark was not to die; and if anywhere in this history we are to find the roots of physico-chemical embryology, we must pause to recognise them here.

Much less well known, but not without interest, was the Dirrertatia J2 vita F 0cm: in Utera of Gregorius Nymmanus, which was reprinted in the same year as the second edition of Descartes’ book, 1664. Nymmanus writes with a very beautiful Latin style, and expresses himself with great clearness. His proposition is, he says, “That the foetus in the uterus lives with a life of its own evincing its own vital actions, and if the mother dies, it not uncommonly survives for a certain period, so that it can sometimes be taken alive from the dead body of its mother." In supporting this thesis, Nymmanus answers the arguments of those who had held that the lungs and heart of the foetus were inactive in ulero. Fabricius, Riolanus and Spigelius all proved, says Nymmanus, that the mother and the foetus by no means necessarily die at the same time. "The essential life,” he says, “is the soul itself infomiing and activating the body; the accidental life is the acts of the soul which it perfomis in and with the body.” Though the foetus cannot be said to have life in the latter sense, it can in the former. The foetus, says Nymmanus, prepares its own vital spirits and the instruments of its own soul; there is no nerve between it and its mother. If, he says, the foetal arteries got their Sphygmic power from the maternal heart, they would stop pul- sating when the umbilical cord was tied, but this is not the case. The pulse of the embryo is therefore due to the foetal heart itself. Galen, says Nyrnmanus, was aware of this, but did not understand the meaning of it. Again, the foetus in utero moves during the mother’s sleep, and vice cnm. Nyrnmanus' dissertation is an interesting study in the transi- tion from theologiml to scientific embryology which took place all through the seventeenth century, and may be followed in the writings of Varandaeus, de Castro, Dolaeus, Hildanus, Scultetus, Ammanus, Augerius and Garmannus. The problem of animation-time, a more metaphysiml aspect of the same question, was still being handled, but

less attention was being paid to it than formerly. Honoratus I-‘aber's De Germa!r'oneAm'maIx'um of 1666 does not belong to its period. Its author, a Iesuit, proceeds in scholastic fashion to lay down four del:mitions, three axioms, one hypothesis and _.,,vemy_se,,m propositions, in the last of t\'luc.h he summarises his cgn¢1us;0,,5_ He 51 xntlircstixigm that he disphys a gisbeucr in 5p,,,m,,,¢,,,_,s gm,_.,;,,;,,n, Here Y 8ntlC1PJfm8 R€dl._and he Is Careful to mention the mark of

31'V'€_)’. but fl€‘v'.€flhCl§S his treatise is of little value. His chief import- ilifllate Is ‘that he [5 an epxgenesxst, and therefore demonstrates to us how I t opuuon “as becoming accepted, when MaIpigl:i's brilliant ob- servations and bad theory sent it out of favour, and prepared the way for the numerous controversies of the following century.

8. Fixntivesand Uterine Milk ;Robert Boyle andWalterNeedham

It was in 1666 also that the following appwed in the P}u‘Ia:npIu'mI Trmtrarlionr of 11:: Royal Society:

A may of prerming bird: taken out «J the eggs, and other smallfaeluftz communicated by Mr. Boyle.

When I was sollicitous to observe the Prucesse ofNarurein the Formation of the Chick, I did open Hens Eggs, some It such a day, and some at other daics after the beginning of the Incubation, and carefully taking out the Etnbryn'.s, embalmed each of them in a distinct Glass (which is to be artfully stopt) in Spirit of Vline : Which I did, that so I might have them in readinesse to make on them, at any time, the Observations, I thought them capable of aflarding; and to let my Friends at other seasons of the year, see, both the ditfering appearances of the chick at the third, fourth, seventh, fourteenth, or other daies, after the eggs had been sate on, and (especially) some particular: not obvious in thickens, that go about, as the hanging of the Gutts out of the Abdomen, etc. How long the tender Embryo of the Chick soon after the Punctum saliens is discovenable, and whilst the bodie seems but :1 little organized Gelly, and some while after that, will be this way prcserv’d, without being too much ahrivel’d up, I was hindred by some mischances to satisfie myself; but when the Faetus‘s, I took out, were so perfectly formed as they were wont to be about the seventh day, and after, they so well retained their shape and bulk, as to make me not repent of my curiosity; And some of those, which I did very early this Spring, I can yet shew you. .

Boyle said in conclusion that he sometimes also "added Sal Armo- niack. ahounding in a salt not some but urinous."

In the following year (x667) there appeared the De Formalo Form of Walter Needham. Needham was a Cambridge physician who went to Oxford to study in the active school of physiological research which such men as Christopher Wren, Richard Lower, John Ward and Thomas Willis were making famous. His book on the formation of the embryo, written later (and dedicated to Robert Boyle), after he been in practice in Shropshire for some time, is important because at is the


(B) Exmm foctum equlmlm qucrn. quiz ad numus nan en: thalcugrlphn Dslendendus, ego rx memom dtscrlpsl‘

Illuxlmlinnsfrnm Walter Needham‘: D: Forrnalo Foctu of 1667. The up/zzr one u uu nrmlar la, but run. an Len-I: xugzm, ademxml «nth, Fig. 29 of Plait X! I’ in De Fon-nato Foam 42/‘ Fabriritu (1’em're, xéaa).

first book in which chemical experiments on the developing mammalian embryo are reported, and also because it contains the first practical instructions for dissections of embryos (see Plate X, facing page 158).‘

Sir Thomas Browne had, as we have already seen, made experiments of a chemical nature on the constituents of birds’ eggs and of the eggs of Amphibia, but he did not analyse them after any development had been allowed to take place. He may therefore be regarded as the father of the static aspect of physico-chemical embryology, while Walter Needham may be regarded as the founder of the dynamic aspect. The practical difficulties of these pioneers of animal chemistry may be seen in such a book of practical instructions as Salmon’s General Practire of Chyrnirtry of 1678. They had no satisfactory glassware, no pure reagents, the methods of heating were incredibly clumsy, and there were no means of measuring either heat or atmospheric pressure.

In the review of Needham’s book which is to be found in the Philo- sophical Trarmzctionr of the Royal Society for September X667 there occurs the sentence, “These humours (the amniotic, allantoic, etc.) he saith, he hath examined, by concreting, distilling, and coagulating them; where he furnishes the Reader with no vulgar observations.” What were these observations? They are to be found in the chapter entitled "The nature of the humouxs”:

I now proceed to speak of this other nutritive liquor round about the urine itself which latter is plainly separated by the kidneys and the bladder. These liquors also proceed from the blood and seem similarto its serum but yet they are different from it. For when fire is applied to them in an evaporating basin (cochlea) they do not coagulate, as the blood-serum always does. Indeed, not even the colliquamentous liquid of the egg itself coagulates in this manner, although it is formed from juices which are evidently liable to coagulation-— in the same way humours difier among themselves before and after digestion, filtration, and the other operations (mangania) of nature. All, when distilled, give over a soft and mild water (mollnn at Imam) very like distilled milk. This property is common to the liquor of the allantoic space, along with the rest. Because when the salts are not yet made wild and exalted the serum of the blood remains still quite soft and does not give proof of a tartaric or saline nature. Indeed, the first urine of an infant is observed by nurses to be not at all salt, but in older animals, when I distilled it in an alembic, I seemed to observe a little volatile salt at the small end (in capitello). Coagulations attempted by acids happened diflerently in rapect of the different humoura. For when I poured a decoction of alumina into the liquor of the cow's amnios it exhibited a few rather fine coagulations but they were clearly white. The nllantoic juice, however, was predpitated like urine. Spirits of vitriol and vinegar brought about lest esults than alumina ‘ ‘ concretions I found also lflrlllc later months; l§l:Se:cIhflc'l:SO:'¥'E'l:Enl£:nl:l’l: Pl3°°9- Th?! 3!! 111011: frequent and larger, however, within the allantoic membrane.

‘ Some information concerning Walter Needham and his trier-ids, especially John R1)’, the botanist, is contained in RnvI.'n'l book 1711 the latter.

From the above excerpt, which contains the account of all that N - ham did on the cherniml composition of the embryonic liquids it can be seen that he treated the whole matter more dynamigllgr than Browne. He was the first to describe the solid bodies in the amniotic fluid (hipponmnes, see Ienlnnson) and his chemical experimentation was all pioneer work.

His book other merits, however. In the first chapter he refutes the theory which Everard had propounded, that the uterine milk was identical with the contents of the thomcic duct, conveyed by lymphatic vessels from the laetmls of Aselli to the uterus, instead of elsewhere; and he Sl]O“‘S that arteries must be the vessels bringing the material to the womb. The second chapter deals with the placenta,

where he giveth a particular account of the double Placenta or Cake, to be found in Rabbets, Hares, Mice, Moles, etc., and naininea the learned Dr Wharton's doctrine, assigning a double placenta to at least all the viviparous animals, so as one halfol’ it belongs to the Uterus, the other to the Chorion, shelving how far this is true, and declaring the variety of these Phaenomena. Where do occur many uncommon observations concerning the difierenee of [uterine] Milk in ruminating and other animals, the various degrees of thick- ness of the uterin liquor in oviparous and viviparuus creatures.‘

He describes the human placenta correctly enough.

The use of the placenta is known to be to serve for conteighing the nliment to the foetus. The diflicttlty is only about the manner. Here are examined three opinions, of Curvey, Everhard, and Harvey. The two former do hold that the foetus is nourished only from the Amnion by the mouth; yet with this difference. that Curvey will have it [ed by the mouth “hen it is perfect. but whilst it is yet imperfect, hy mcmion through all the Pom 9f the body. and by a kind of juxtaposition: but Everhard. supposing a simultaneous formation of all the instruments of nutrition together and at first. and ¢8N‘€1Tf' ing the mass of blood by season of its asperity and =1zemI§ CO! |“-“-“' tion, and rather apt to prey upon than feed the pans. n|3'-'.3‘1m5v W‘ ‘h’ liquor is sucked out of the amnion by the mouth, concocted the stotnzcka and thence passed into the Milky Vessels even from the beginning. Mean- time they both agree in this, that the embryo doth breath but not feed through the umbilical vessels. This our Author undertakes to disprove; and having

rrcursor of am comparative may nf pl-cm‘-1

the elassifiation oi

.m.m.n and funetmn which reached definitive rational"! in Gmm-(:g21)-

asserted the inildness of, at least, many parts of the hloud, and oonsequently their fitness for nutrition, he defends the Harveyan doctrine of the co1liqua- tion of the nourishing juyce by the Arteries and its conveyance to the foetus by the veins.

In the third chapter Needharn gives the first really comparative account of the secondary apparatus of generation, enunciating the rather obvious rule that in any given case the number of membranes exceeds the number of separate humours by one.‘ He affirms that all the humours are nutritive save the allantoic. It had previously been held that all fish eggs were of one humour only, but he points out that a selachian egg has its white and yolk separate. He gives the results of his chemical experiments at this point, and suggests that the noises heard from embryos in were and in we may he due to the presence of air or gas in the amniotic cavity, thus forming a link between Leonardo and Mazin. In his fourth chapter he deals with the umbilical vessels and the urachus, and here he claims priority over Stemen for the discovery of the durtus 1'nIexti'naIz's' inthe chick, referring to Robert Boyle, Robert Willis, Richard Lower and Thomas Millington, to whom, he says, he showed the duct before Stensen published his observations on it. The fifth chapter is concerned with the foramen ovale, and the arterial and venous canals, and with the foetal circulation in general. The sixth is about respiration or “biolychniu.m,” and in it Needham writes against the conception of a vital flame, alleging cold-blooded animals, etc. in his favour, but here he takes a retrograde step, for he argues that the use of the lungs is not for respiration but to "comminute the hloud and so render it fit for a due circulation." '

The seventh and last chapter contains a direction for the young Anatom- ists, of what is to be observed in the dissection of divers animals with young: and first, of what is common to the viviparous, then, what is peculiar to sevcrall of them, as, a sow, mare, cow, ewe, she-goat, doe, rabbet, bitch, and a woman, lastly, what is observable in an Egg, skate, salmon, frog, etc. All is iilmstrated w'it'h divers accurate sciicmts.

‘ For the icvgrireei-iih-century and inter folklore of the embryonic rnzi-nbnncs (cf. the "Silly Haw," etc.) 1:: Brand, esp. p. 405-

' The ducmr inlextinalix, which connect: the IV]!!! yolk with the giicot the embryo, has n peculiar importance in the history of embryology, mice it provided one of the imin arguments on the prefui-muioi-iis: ride at the cliimx of that debate (It: p. r99: and Fig. 2:). . _ _

As Adzlmann rightly remiirlu, it was known to Aristotle (Hi:-Inna, 561‘ . Central. 7 :1: ,°)_ “,4 H, coke,’ who spurt, of gn outgrowth from intestine to yolk. o meniion o It i. mlde by Aldrovandus. Flbricius or Harvey. ii; res, Appeared sgenit-in DE n'I:Ili' in ivilutina pulli rransilu Epixlola (bound up with his De liluiculu at Gland. Obxtrvaliorrum Specimen) in which the miiscoveryms made. but W. Nccdham hzd I priority of ten years, as described in the text. See Muf-

Th‘ 3'-'b5"l"°m “"59 Of fihemical embryology in the seventeenth Dentury {nay he put in a very few words. Marguerite do Tertre incog. poi-nted in her obstetrical text-book of 1677 the results of some similar experiments to those of Needham. “If you heat the (amniotic) liquor " she says, “it does not coagulate, and if you boil it it flies away lmving’a crass salt like urine, but if you heat the semsity of blood, it solidifiesns if it were glue." The same observation was recorded by Mauriceau in 1687, who concluded, with some common sense, um, 93 mm mg 3,, little solid matter present, the liquid could not be very nutritive; and by Case In 1696, who said,

In this juice the plastic and force ruides, for although to our eyes it looks in colour and consistency like the semm of the blood, yet it is abso- lutely (Into toelo) d.ifl'erent; for if I little of the former is slowly evaporated (si in cochlear!" ruper rggrmn denier) no coagulation will eser appear.

Lister said this once more in 1711, but with Boerha:rve's wad: of 1732 the subject entered a new phase.‘

9. The Discovery of the Follicles of the Mammalian Ovary

In 1664 Nicholas Stensen, that great anatomist, later a bishop, who was also in many ways the founder of modern geology, produced his De murculir at glandu/it lpecimm, in which Coiter’s observations on the vitelline duct and the general relations between embryo and yolk in the hen’s egg were made again and confirmed. About this time also Dcusingius described his case of abdominal pregnancy, and was thus the first nnatomist to draw attention to this phenon.

In 1667 Stensen published his Elemznlannn myalagiae xpminm, in which he described the female genital organs of dogfishes. He damm- strated the follicles in the ovaries and aflirmed that the "testis" of women ought to be regarded as exactly the same organ as the "ovary" or "roe" of Ovipara. At the time he carried the suggestion no further. and it is surprising diat it did not arouse more intermt, for it was exactly what Harvey had been looking for. Nothing obvious found in the uteri of King Charles’ does. and the mm-ictmm yet hem: my strong that viviparous conceptions rally more frm_n ‘E85. Stflliflfl minute ova supplied the fitting answer to the qnmtron. Thu: Harvey and Stcnsen between them substituted the modem concept Of Imm- malian ova for the ancient theory of the ooagulum all In the space of fourteen years.

In 1670 Theodore Kerckrwg Pullhshd wk °“ ‘Mm

I Ebstein has written the history or en. boilinfl lest fw rmdn in W?"-

osteology (see Fig. 16), and, two years later, de Graaf and Swammer- darn described in detail the follicles of mammalia (see Fig. 17)» thus demonstrating the truth of Stensen’s suggestion of some years before.‘ It is important to note that these workers_mistook the “Graafian folli- cles" for eggs—a mistake which was not rcctified till the time of von Baer. Stensen himself not long after also published an account of these “eggs,” but he was by then too late to gain the priority of demonstration. Poi-tal’s claim that Ferrari da Gr-ado, who lived in the fifteenth century, was the true discoverer of mammalian ova has been disproved by Fer- rari,‘ and, although it is true that Volcher Coiter mentionedwhat we now call the Graafian follicles, he did not recognise in any way their true nature.

De Gr.1af's discovery was confirmed in 1673 by Caspar Bartholinus, and, in r674, by Langly, whose original observations had been made, so it was said, in 1657, the year of Harvey's death. If this is true, Langly has the priority of observation, Stensen of theory and de Graaf of demonstration.‘

The concept of biological homology originates from Harvey, Stensen and de Graaf, according to Tur. The mammalian ovary was recognised as homologous with the ovary of the oviparous animals. In this con- nection, the work of Nuck in 1691 is very important, as one of the earliest instances of experimental procedure. He ligatured the uterine horns after copulation in a dog, and observed pregnancy afterwards, implantation having taken place above the ligature. His conclusion was that the embryo was derived from the ovary and not from the sperm— animal ex we generari experimenlo probatur. His work was repeated almost exactly me years later by Haighton, who drew almost exactly the same conclusion from it.‘

ro. The Micro-ieonographers and Preformationism-, Marcello Malpighi and Jan Swammerdarn

In the year 1672, Marcello Malpighi, who had for many years pre- viously been working on various embryological problems with the aid of the simple microscope,‘ published his tractates De Ono Incubate

‘ Se: Meat. The words nmlierum tester ocnri: muzlogi um: appear in Hirl. Dirrzd. Pin-ii, lunar‘: edition. vol. 2. p. 153.

' Una Chair: dc Illldccine . . .. pp.‘ H5 ff.

' See Tur. Cole (p. 48) believe: t t the first use of the term "ovum" {or the ovarian follicles of mammal: in print is in van Home’: Pmdmm-ur of 1668. The idn was cvidtntly widely current In these two decades.

‘ See pp. 109-19 and 236.

Biblmgnphy of the history of the microscope by 0, \V. Richards. 0! the large lnenrurc on this nlbjtct we may mention only the introduction: of llooruboorn and Hinzzsche; and the paper of Hughes on Ichromatum.

I63 Fig. 16. Thmlm Kmluing‘: imagfnalire a’ mz-Eng: u/luun.[¢p..,.; (167.2) Iahmfram Phil. Tnns. zéy. Soc., 167:, .g_ .11, ,5 4913 I, Fig. I. "A Artur-ix nflh in chfqfdzptndaznczr." . Fig. II. "Egg! of «Initial! bignux. as Dr Knknngin afinu fu In-on [maul [Inn in llne ftrttdd of a fT'ormrn.”

Fig. III. "A bigger Egg." .

Fig. IV. "Smallzr Eggxfmm the Iexhzkx aft: mIf’—(Grnafianfum‘dg).

Fxg. V "npr¢:¢-rm an Egg. Rind! Dr Knktfngxux qflfnu In hm: opznaf av ( dot‘ [sic] “after it Iraxfallm Em um Mama: up man, nndiu ' htuza um tulle zmbryun marhd B, tahtuaf he /mmd the land bqun M M from the body, yet without a d::m'u:1 pretrpffall allhgoygmn.”

F .171 “ En’ .0x>en:d I tm'Iu[']dlerun:r)mm." VII, “ 77:: ;:c!:'ta:v.§:,fyr:cfa:zI:3nar¢kr. (mush:-dfiuuvhnjia

mneeptnm [sic]. ' Kncbfng 1-imply drew minted rnpie: nf III: xhzldm J M: newborn Fulani.

(Bxl¢'k:‘az1::, p. 96,) 164

65 Fig. 17. Illwharinmfram "Rcgneri dc Gnnf Opera Omnin" (Lugdurfi Bataoorum E: wig-x'nn Haeldana, 1677)

A. Tab. XXVI. Evhilul Ova mm in amimlamm utera Iepniunhcr.

0. Tab. XVI. Exhibel Tem‘ um nu Osmium Mulia-1': am annrm Thbamm lxtmno. C, Tab. XVIII. Gallinu Pam: Genilalat exlubtt.

and Q: Formatione Pulli in 01:0. In spite of its great importance, it was anyllung but a voluminous work. The plates in which Malpighi re- presented the appearances he had seen in his examination of the em- bryo at different stages are beautiful, and I reproduce some of them here (Fig. :8, below and Plate XI, opposite). Description of the embryo was now pushed back into the very first hours of incubation, and it is interesting to note that Malpighi could not have done his work without Harvey, whose name he mentions on his first page, and who pointed out the cicatricula as the place where development began, and therefore, as Malpighi must have reasoned, the place where microscopic study would be most profitable. Now for the first time the hlastoderm was described. the neural groove, the optic vesicles, the somites and the earliest blood-vessels.

Malpighi appears to have been anticipated, as regards the first de- scription of the chick's heart pulsating in colourless blood. by HEM)’ Power, M.D., of Halifax (a friend of Sir Thomas Brow-ne‘s), whose charmingly written l’:‘.zp:rim:n1aIPlu'la:apIry appeared in X664. Power confirmed microscopically the opinion of Parisanus (see p. n6).

For view but an Egge [he say: on p. 60] after the semncl days Incubation,

and you shall see the cicatrieula in the Yolk, dilated to the breadth of a gmat

or six-pence into transparent ooncentriml in ‘hf c¢1m'5“’l“1'°°f is 3 white Spot. with small whrte threads (whreh in furunry proves the with its Veins and arteries) but at present both ti: motion and cuculauon is

my arm:


lllumanmu from .\IalpI'ghf': De Om Xncubam of 1672 xlnmmg llxt tnrly mzgu of the deulaprnerxl of the chick (rampart mm L.11.2'; movwgmp/I).

Fig xvx (left) shows me and luuulosa and the embryo u Iboul as hauls‘ Incubation; u rnnd G me \ nzllm: u-sscls, n n the lnll';!lI1IlVCil'L at n the Imrnor utdlme turns, .2 D (hr lemurs of “inch in hm bun drnwn. an xv: (right), xvu nnd xvxu Illusxrne Ihe formulon or uh: hart \I:lp)gh| saw 1:. They - at gmx imms: .. they show me nnruc mm. In mg. xvn the non n- M represents the confluence of mg two cmphzlomesemeric mm coming [mm me yolk- nc. ma ludmxz mm uh: ductus unmus. L. I: L: jmned nbov: by the Duct or Cuutr (upper 11) from the animal \cm or me tmbryumc body (cf. Lnllne, mg H5). In Fug. xvm the vase! K mu ulnmllely became the vcnz clvn. x Is the lunch, L me \cnmcl¢ um .\I the bulbus (cf. Lulhe, Fig. I97). A: N Ire xhuwn mm norm: mrm, connetung the hurt vmh [hr mru. Thur signifi- unc: mu no: .p,ma'mann Ihe ume or Ruthie, who m 1825 drmanslnled the fish-lxk: g.1x.nn_. and gill-uthcs In 1h: crnbrym or birds Ind numnuls. PLATE XII

Illuxtraliarrt/ram "The curious and mxurare obscnatmns of .\Ir Stephen Larcnzim of Florrnce on the Dlssectmns of (h: Cramp-Fish : tonrafnmg the mmpamme mmlamy of that and some mlm Fub, u-1'11: Expuimenu. Dedrumd In In: Jim Snnle Hxghnru 11.: Print of Tummy, and mm dun: mm Englulnfranx we lmmm, mt]! Frgmn‘ after the L:fe_ by]. Drrrix, 3|! D jzfler) Wale, I.muiarI", 1705

A. Tm: HI. Hg. 5 (lb: “mu tinge), the (Q arm. camp-Fsh. aaaau, xhe wan: Cnrtlc or Cncamx; Db, . cznam Cqlllquamenmm of: luden calnur, :,u.. am ma: Dnughx mm Amman dd, . «mu strip: or Sclwdgv: art, mu: Bladdrn of unmu rmm and dafluvnt Bxgnesl; 17 . cerum mu: Hag; ggzt. : Lug: Svrnthe .7. Bordering, m some plans oi . Sub phureau colour; 1.1., Anotbzr circle of thc Colhqunmuxxurn; u, . «nu: Dd: or emu.

c. Tnbic n'. Fig 2 (lam)

B and D are ukm from phutugraphl arzuglu-3. see mu.

undiscernable to the bare eye, by reason of the feebleness thereof, and also because both the Liquor and its Vessels were ooncolour to the white of the Eggs they sworn in; but the Heart does circulate this serous diaphanous Liquor, before (by a higher heat) it be turned into bloucl. And one thing here I am tempted to annex, which is a pretty and beneficial Observation of the Microscope, and that is, That as soon as ever you can see this red pulsing Particle appear (which Doctor Harvey conceited, not to he the Heart, but one of its Auricles) you shall most distinctly see it, to be the whole Heart with both Auricles and both Ventricles, the one manifestly preceding the pulse of the other (Which two motions the bare eye judges to be Synehronical) and without any interloping perisystole at all; So admirable is every Organ of this Machine of ours framed, that every part within us is entirely made, when the whole Organ seems too little to have any parts at all.

The cloven hoof of preformationisrn may be observed in the last few lines, and their chronological position should be noted.

Recently Cole has brought to light another anticipation of‘Malpighi, even more interesting, if not so reputable, as the preceding. On March 14th, 1671, William Croone deposited with the Royal Society a manu- script paper on the development of the chick; in Hue following year a brief abstract of it was published in the Philosophical T rmtxatiinm, but it did not appear in full till 1757. Croone examined by dissection the cicatricula of the hen’s egg, and gave an illustration purporting to represent the preformed embryo, but obviously recognisable to modern eyes as a fragment of vitelline membrane accidentally carimturing the features of 2 bird. "Croone's paper,” says Cole, “is important, not on account of its merits, which are negligible, but because it is the first reasoned attempt, based on observation and illustration, to establish the corporeal existence of a preformed foetus in the unincubated egg." Croooe rather naively admits his preconceived bias in favour of pre- formation. or rather of "instantaneous generation," followed by "meta- morphosis," but does not indimte whence he derived it. Joseph de Aromatnri, Swarnmerdam, Highrnore, were all possible sources.

Among the immediate followers of Malpighi was Lorenzini (see also p. 207), a Tuscan investigator whose merit has apparently been over-

looked. A pupil of Nicholas Stensen and Francesco Redi, he published in 1678 (six years only after Malpighi's De Ow Incubato) a descrip- tion of the anatomy of the elasrnobrancl) fish T arpeda, plentiful then no doubt as no\v at Naples. An English translation appeared in 1705.

Lorenzini recognised the ovary of this fish as homologous with that of the hen. and studied the early development of the eggs, giving two semi-diagrammatic pictures of the blastodisc. These are reproduced

"1 P1319 X”. facing page 167. In the earlier one, shown side by side with a modem representation of Ziegler’s, the medullary groove is scgn growing forward over the surface of the blastodisc, and Dorenzini has tried to indicate the presence of the little distinct swelling: which are formed by the segmentation mvity. In the second picture he 1135 correctly shown the outspread cephalic end of the medullary plate which closes later than the rest of the neural tube, though he dots noi figure the neuromeres. No explanation is available for what he describes as a “little bag" (f, T, in the first figure, 2, 2, in the second), unless it was a tumed~up fragment of the hlastodiscfl

It is always considered that the modern phase of the controversy over preforxnation mm epigcnesis began with Malpighi, though the firm- ness of his convictions on this question have been much exaggerated. Emhryogeny, preformationists held, is not comparable to the building of an artificial machine, in which one part is made after another part, and all the parts gradually "assembled,” but takes place rather by an un- folding of what was already there, like a Japanse paper flower in water. Malpighi was led towards this belief by the fact that development goes on after fertilisation as the egg passes down the oviduct, and in the most recently laid eggs gastnrlation is already over, so that in his researches he could never find an absolutely undeveloped germinal spot. It is curious to note that he says his experiments were done mmse Augurri, magno evigmte mlore, so that a more than usual degree of development would have taken place overnight. Had he examined the eieatriculae in hen's eggs before laying, he would very probably not have formed this theory, and the epigenesis controversy might have been settled with Harvey. Another influence which Wu unfavourable to the epigenetic position was that it was Aristotelian, and therefore unfashionable. Yet Malpighi’s view was much more sensible than many which succeeded it, for he did not maintain a perfectly equal swelling up of all parts existing at the start, but rather an unequal unfolding, a distribution of rate of growth at different times and in diflerent regions of the body.

Thus he says,

Now, as Tully says, Death tnrly belongs neither to the living not l0 the dead, and X think that something similar holds of the first beginnings of animals, for when we enquire artfully into the production of animal3_out of their eggs, we always find the animal there, no that our labour is repaid and we see an emerging manifestation of parts successively, but never the first

origin of any of them.

fishes. Duverney (1643-x73o), for uxmple, Itudied the hurt ofthe tzrp Ind rt: d¢vdU

What had been unfounded speculation for Seneca in antiquity and for Joseph de Aromatari and Everard in late times was now set upon an apparently firm experimental basis by Malpighil

It is most instructive to note the difference in the attitudes of Langly and Schrader respectively towards the prefomiation question. Langly has no doubts about it, nor has Faber; they both follow Harvey and epigenesis unquestioningly, but Schrader, though he believes in epigenesis on the whole, is not at all certain about it. His friend, Matthew Slade, he says, brought the epistle of Joseph de Aromatari to his atten- tion, and what with that, and the unexplained observations of Malpighi on the pre-existence of the embryo, he is not willing to deny all value to preformationist doctrine. Others were bolder. It was immediately seized upon by Malebrauche, the Streeter of his age, who, in his Recherche de la Vér-fie‘ of 1672, realised its philosophical possibilities, and gave it a kind of metaphysical sanction. That mystical microscopist, Swammerdam, made use of it as an explanation of the doctrine of original sin. In a remarkably short space of time it was a thoroughly established piece of biological theory.

Malebranche refers to it in his Recherche de la Ve’1i!e' in the chapter where he treats of optical illusions and emphasises the deceitfulness and inadequacy of our senses.

We see in the germ of a fresh egg which has not been incubated an entirely formed chicken. We see frogs in frogs’ eggs and we shall see other animals in their germs also when we have sufficient skill and experience to discover them. We must suppose that all the bodia of men and animals which will be born until the consummation of time will have been direct products of the original creation, in other words, that the first females were created with all

the subsequent individuals of their own species within them. We might push .

this thought further and belike with much reason and truth, but we not un- reasonably fear a too premature penetration into the works of God. Our thoughts are, indeed, too gross and feeble to understand even the smallest of his creatures.

Malebranche, who was a priest of the Oratory of the Cardinal de Bérulle, took an ardent interest in the scientific life of his time‘—for example, in a letter to Poisson, the Abbé Daniel wrote, “Reverend Father, M. Male- branche has writtm to me saying that he has installed an oven in which

‘ For léxe earlier part of this min of thought, 2:: pp. 66 Ind in; for the later, we pp. 21 3 .

' Just is Christian theology led some xeventeenth—century thinkm to take an active interest in embryologieal phenomena, so in earlier centuries Buddhism in China had stimulated speculation Ind some obszrvltion on rneumorphosis in plants Ind Inimlh (see Science and ciuloazion in China, vol. 2).P1m xm. facing page 17¢, show: this

12:-ring‘: Buddhiu iconography, the "putting oil’ of the ‘old man’ " in delivernna: mm uuon.

16 la: hgtched eggs. {is has already opgned some and has been able to C6 ‘ e "earl formed in them and heating, together with some of the artenee.

Swnmmerd_.1m‘s supponforprefonnation came from a different angle. He had been investigating insect metamorphosis, and, having hardened the cltrysalts yvrth alcohol, had seen the butterfly folded up and perfectly formed within the cocoon. He concluded that the butterfly had been hidden or masked (larwtru) in the caterpillar, and thence it was no great step to regard the egg in a similar light. Each butterfly in em, comm mu_st contaur eggs within it which in their turn must contain butterflies which in their turn must contain eggs, and so on. Before long, Sn-am. merdarn extended this theory to man. "In nature." he said, “there is no gmemtuon but only propagation, the growth of parts. Thus original sin )5 explained, for all men were contained in the organs of Adam and EVE. Yhon their stock of eggs is finished, the human race will cease to e.

In r684 Zypaeus reported that he had seen minute embryos in un- fertilised eggs, and there were other similar claims. Him: 7rmxlr'or:.r phyriolagi, said Schurigius in 1732, Ixorrrinem in avulis dclineahrm quoad armies perm in e:n'g'zIit .mzrm'm'I>ur ante tonttplianfln exirtere rlalmmt.

Swammerdam cannot be regarded simply as one of the principal pillars of the preformation theory. His own crnb1'.V°l°8l°3] ‘T55-'“’Ch¢9. which were made chiefly on the frog, were remarkable in many Ways. He was the first to see and describe the cleavage of the egg-cell and later segmentation. He said that there was a time during the development of the tadpole when its body consisted of granules (gfomkm 0!‘ 721001;?!"-V). but as these grew smaller and much more nurncfous they Csfilpcd his penetration (see Fig. r9). Leeuwenhoek also saw these cells.’ and his actrrunt was published long before Swarnrncrdam'5. hut hi5 0hS€rV’«1ll0n5 on the rotating embryos of Anodon and the eggs of H635 Were equally interesting.

rr. Foetal Respiration and Composition; Jchn MSYOW and

Robert Boyle In 1674 John Mayaw, a young Oxford physician, published his tr-rotate, De Rrrpiratione Form: in Utero cl Ova, which W31’: included 35 one of the parts of his T racmtu: Quinque inediro-pllyxici in that year. Mayow was the first worker to realise that gaseous oxygen. 0?. 35 5°

gehefll"lfi;13’(1lV‘;. ?Ic1sr1c;|rp:ag:rl7t. Dobcll‘: boolg on Le¢ by certain Inpses of txste, irprobably the most considerable gum: wf l=vznteenth—c:.ntury_ biologist aunt. Unfonunnely, he co hum.“ hm“ _ er-iption and mtumon only or the prottuoolognml ma bmemlom 0 um"-



Portrait of Am». can Lenmenlwzk (1632-1723) by Jon. Vnlzol/2 (:65a—93) m 1636, am in nu R:)lupru.mun. Amnndam.

Km Fig. 19. Observation: on (It: rlmvage of the amphibian egg.

A. The fin: inure: :2] the 2-all xlagz, frmn "Johannis Swaxnmerdammii Bibha's') (Ley en, apud Ixaaalm Seuerinum. Balduimnn Vamln An, Pzmnn Vflfldtf

H.173 -

Elaxlonxeus of the frag‘: eg at lha 2-cell nag: an xhmn in Tab. XLVIII, figx. V, VI. VII. VIII.

(9. 82,7) "in 1: fig. Van, Pono ofimvabam. Rmmnculmn mu’ m-um, nambfli aim- dmn rulzn .-iv: plxcahnu, in dun: ueluti pants d ":11" :1, a. . . . . . ..IIa::c: uulan obmvalio mics’ 1:2! plicatuiae tarpon’: Ranunmli; quarn qnidem, mm mlmn ormita p ' nu a me nnimadrevxam, in via‘: paxhnodmn Rnmmtulis quoque dmxn’; p urfnvum 1nx'In' dein adfnebal [mix at! urn'u! cximmandum dc subila illa wrpuxndi Rmruntulorum zxpam-iwu El elmgatime, gun: die quarto, cum Embrya we axpluul. tvenirz emxfmr. Credxdaim Ixine, quad allrva illa txplxzali Rmmneulipan in Caput :1 77mra::m an-rural; alien: mo In Abdovntn alque Cuudam, qua: pedztentfm mqgz: augelur."

p. -914) "in 12 fig. VII. . . . In media huiu: Om‘ mamfzxte nm-u: demfptum ant: I: cmupiul-barn."

Wm: obravalimu Inn mad: betumn 1665 and 1675. In 1676 Oligmu Jarobaeux pnblirlml H: "De Rania Obscrvationes" (fiillame, Pzrir). Ht} illuxtralionx thou: the rail- bud nagu but no blauomem. On pr:/annatian II: appear: ta agree with Swammen darn mtlxei than with Harvey.

B. Thzfinl icnnu cf the 4-011 xfagz,]1om “Expérience: pour sarvir ) Phisxoire de la génémupn es ammnux ct dc: plantcs"; par M. l‘Abbl Spallanzani (ed. Sembier), Earl/ulnnx Clxiral, Geneva, 1785.

(9. 36). “II: yesmnblznt d J: fifiu globe: noin qua’ pa-rvinvnt rand: d I'm‘! mad 2: «cu une lenulle faiblz; mm‘: 11' on obmva nut: mufon: Ientille, on 1:: unit xillarrnlr dz qmum :1'IIo1u gut :2 muptnl 1) angle: draft: rlnmn: In puru d dzmf-mnxvlz dz: chfixaigna nu dz: nmronx, Fig XI. Quofzrue m peril: nuom Ill mm: pa: mnir, mm": eouverh arm mmbmne til:-:ab.'tl¢ qui nmlap/at ézmitemrnt I: rule :1: I'¢uf,- n‘ I ‘on are cut: membrane, on um’! J dlcouxml la pmu appnn-M2 dc hm] qua’ ex: naive 1! gm‘ :2 dlrhin pay I: plu: Ilgn allmachernznl, avtc l'inl!n'tur dz I'¢uf don! In nabxmncz 2:1 pruq-ue fiuide, d'Ime mulzur pruquz Handle, lumogéne, on n‘nu'lm'ra en apparnlce, cmnpoxéu depenm panimlu gzbulleuug quand on l'ob1-ave ave: vn nu':1ormpe." (Ix this the zavliex-1 mention o/yo!Iz- p 1: us

“fined it. the "nitro-aerial” vapour, was the essential factor in the burning of a candle and the respiration of a living animal. His Work “as forgotten until Beddoes drew attention to it in r79o, bu: sincg mm many have praised it and Schultz: makes him the equal of Harvey.‘

The reason why he became interested in embryology is given in the opening sentences of his work.

Since the necessity of breathing is so essential to the sustaining of life that to be deprived of air is the same as to be deprived of common light and vital spurt, It will not be out of place to enquire here how it happens that the foetus can live though imprisoned in the straits of the womb and completely desti- ture of air.

He firs! of all gives an account of the opinions held about foetal respira- tion and the umbiliml cord. He says that he disagrees (1) with the view that the embryo breathes per os while it is in the womb, for there is no air in the amnion and the ruttia fnfanruli proves nothing; and (2) with the view propounded by Spigelius that the umbilical vessels existed to supply blood to the placenta for the nourishment of the latter. It‘ this were the case, he says, the membranes in the hen’s egg could not be formed before the vitelline vein, as drey are, and in casu of foetal atrophy the placenta would always die and be oorrupted too, which does not happen. Nor does he support the view of Harvey (3) that the um- bilical vessels supply blood for the concoction and colliquation of the food of the foetus, for why should not the embryonic body prepare its own nutritious juice before birth just as it does afterwards. He further

thinks the theory (4) that the umbilical vessels are for carrying of?

surplus foetal nourishment quite untenable and as little likely as the

theory (5) that they exist for the object of allowing a foetal circulation-— for this could just as well be accomplished through the vessels which exist in the embryonic body.

Mayow decides therefore for the opinion of d'l't-{mu Jnrex Hrppoantzr and Everard that the umbilicus is a respiratory mechanism, carcfully dissociating himself, however, from the hypothesis of RlDl«’inl-I3 ll!-‘if 15¢ umbilical cord with all its windings is so arranged to cool the blood passing through it. He flten say$.

We ohserve, in the first place, that it-is probable that the alburntnous Juice exuding from the impregnated uterus Ls stored pvtth no small abundance of aerial substance, as may be observed from its white colour and {mthy eha.rac_- ter [Needham’e uterine milk]. And in further indimuon of this. lift P‘_1‘["' genial juices of the egg, whidt have_ a great resemblance to the seminal JLUCIE of the uterus, appear to abound in atr particles. For if the white or the yolk o

For an extreme view in the opposite direction so: Patterson.

an egg be put into a glass from which the air is exhausted by the Bqylian pump, these liquids will immediately become very Irothy and swell up into an almost infinite number of little bubbles and into a much greater bulk than before-—a sufliciently clear proof that certain aerial particles are most int}. mately mixed with these liquids. To which I add that the humouxs of an egg when thrown into the tire give out a succession ef explosive cracks which seem to be caused by the air particles rarefying and violently bursting through the barriers which confined them. Hence it is that the fluids of the egg are possessed of so ferrnentative a nature. For it is indeed probable that the spemiatic portions of the uterus and its carunculae are naturally adapted for separating aerial particles from arterial blood. These observationg premised, we maintain that the blood of the embryo, conveyed by the umbilical arteries to the placenta or uterine carunculae, brings not only nutritious juice, but along with this a portion of nitro-aerial particles to the foetus for its support, so that it seems that the blood of the infant is impregriated with nirro-aerial particles by its circulation through the umbilical vessels quite in the same way as in the pulmonary vessels. And therefore I think that the placenta should no longer be called I uterine liver but rather a uterine lung.

These splendid words, informed by so much insight and scientific acumen, show that, by the time of Mayow, chemical embryology had certainly come into being. He died at the early age of thirty-six, and we may well ponder how different the subsequent course of this kind of study would have been if he had lived a little longer. The second part of Mayow's treatise is concerned with respiration in the lion's egg during its development, and it may he noted that his observations on the air contained in the liquids before development probably account for the facts which have been reported at one time and another concerning an alleged anaerobic life of embryos in early stages. Mayow was wrong in supposing that the gas which he pumped out from white and yolk was purely "nitroaaerial," but he shows the greatest good sense in his reminder that the amount of nitroqlefial par. ticles required by embryos must be comparatively small owing to their small requirement for "muscular contraction and visceral concoction." His remarks on the effect of heat on the developing egg are not so clear as the remainder of the treatise, but he seems to mean that the heat will disengage the nitro-aerial particles from the liquids, and so aid in respiration, an idea which was later used by Mazin. His fundamental mistake here was that he failed to realise that the egg-shell was penne- ablc to air; and this vitiates all his reasoning about the respiration of the egg. “It will not be irrelevant," he says, “to enquire here whether the air which is contained in the cavity in the blunter end of every egg contrib- uts to the respirttion of the chic " He first notes that the mvity in question lies between two membranes and not between the shell-membrane and the shell as Harvey himself had supposed; and then he gos on to say that he disagrees with the opinion of Fabricius, who had asserted that the air in the air-space serves for the respiration of the chick. His reasons are (I) that there would not be enough there for the needs of the embryo, which would use it, as it were, at one gulp, and (1) that the air in it cannot pass thrmigh the inner membrane, an error into which he was led by observing that if an egg-shell with its contents removed and its air-space intact was put into a vacuum, the air-space would swell up until it was as big as the egg itself. Mayow sees now what had escaped the attention of all previous observers, namely that the egg-contents are not “rarefied or expanded, but are on the contrary condensed and forced into a narrower space than before." Such a condensation could, he thinks, take place in four ways: (a) by an increase in pi-opinquity of discrete particles, (b) by a subsidence of motion on the part of a congregation of particles into rest, (3) by the extraction of some subtle spirit from amongst the particles, and (J) by a decrease in elasticity on the part of some elastic substance previously present. We should at the present time choose the third 2:l!Cf1L’il1Ve.3S being the trust, in view of the loss of water and carbon dioxide ubicli the egg suffers as it develops,‘ but Mayow cl1ose‘ fourth, diinking it probable that the "air distributed among illelumts °f ‘he 983 1°55’ "5 elastic force on account of the fermentation produced among tltfie juiccs by incubation.” Now since the egg—contents are compacted mtg smaller bulk by the procss of incubation, a vacuum would be Craig somewhere if Nature had not: “'59! he‘ ‘f“5‘°‘f““'Y,P'“d‘”°°' msme 3 small amount of air into the air-space whidi might in due coursecxpoafie and avoid this. His proof for this was an inaccurate Ol)SeI'ViIll0Ih' d thought he saw, in eggs at a late stage, when the contents were remoi e -, the air-space collapse to the normal size which it occupies ‘iln unmxc bated eggs. He expressly Sf)‘ 1113‘ his ‘hem’? d°°9 "°t “P2? ‘he conception of harm vnfuz. but that. by the ¢°mP‘¢_55““;‘l Ejbmcal imP"l5"“'d air’ the fluids of ale egg are form} 111;“; zcked more ‘T559151 and ‘ha pamclhs wmpcslng the cmbrymil; 0 same work tightly togethcn “T1” ““°".“‘ 3" “PW” ‘°. P‘ miller toniata are as the steel plate bent round into numerous coils by W 3“ set in motion." . . With this ingenious but erroneous supposition l\la{0i‘1i°!‘$:;liCcla|:d‘C; what is undoubtedly the first great contribution to p. y! “we won biophysical embryology.‘ His views on foetal respiration

l 1%,: féfiaffi; ‘L',,l,Z,6i'.age on metabolinri -nd gmwth during omega-uh. see the trearue of Brady.

generally accepted, as the writings of Zacchias, Viardel, Pechlin and John Ray‘ show, but Sponius as lateas 1684 was asserting that the lungs of the foetus were functional in utero, absorbing from the amniotic liquid the nitro-aerial particles which P. Stalpartius supposed the placenta to be secreting into it. It is interesting to note that by Mayow’s own air- pump method Bohn found nitro-aerial particles in the uterine milk in 1686, and Lang found them in the amniotic liquid in r7o4. The problem had by then arrived at a stage beyond which it could not progress in the absence of quantitative methods.

The year 1669 saw the publication of Nicholas Hoboken’s useful treatise on the anatomy of the placenta, and of the English edition of P. Thibaut's Art of Chymirtry.‘ I mention the latter here because of a reference to the special conditions of embryonic life which is found in it,‘ but as yet no real help was being given to embryology by contempo- rary chemistry.

About this time also Francis Willoughby published his famous book on birds, an attempt to bring Aldrovandus up to date, in which a good picture is given of the emhryological knowledge of the time, although no new observations or theories appear. Another contemporary review is that of Barbatus.

In r677 spermatozoa were discovered, as announced by Ham and Leeuwenhoek‘ in the Philosophical Tranxactionx of the Rqyal Society, though Hartsoeker afterwards claimed that he had seen them as early as 1674, but had not had sufficient confidence to publish his results.‘ There is a reference to this in the letters of Sir Thomas Browne, who, writing to his son, Dr Edward Browne, on December 9th, 1679, said,

I saw: the last transactions, or philosophimll collections, of the Royal Society. Here are some things remarkable, as Lewenhoecks finding such a vast number of little animals in the melt of a cod, or the liquor which runnes from it; as also in a pike; and oomputeth that they much exceed the number of men upon the whole earth at one time, though hee computes that there may bee thirteen thousand millions of men upon the whole earth, which is very many.‘ It may bee worth your reading.

At the same time as these events were taking place, Robert Boyle,’ at Oxford and London, was engaged in continuing those experiments in chemistry which had led him not long before to write his Sceprical Ch_}-mist. It is not generally known that in this work, which appeared

' Wirdom a] God in Cnatian, p. 3. ' See Ferguson. ‘Art, . 257.

‘ On this lubject see Cole ; Ind Meyer (1918); van Buddenbroclr; and Hug es for {urthtr details.

' On this re: Dobell, pp. 69 ff. ' Too many. to convince the avian; Ice 17. 2:3. ' See Plate XV, {Icing page 176.

Fig. no. The inciemt in Ilzaxize of the '-Jpac: / 1}. 110:’: egg afilriag M.-Jopmz, due to (la: 13:’ 0/ Mfr mi co./mt the egg,

in 166.1, and which set the key for the whole spirit of suhsequmt physico~ Chcmial research, Boyle has a reference to embryology, and curiously enough in connection with a point which, though it is easily seen to be of the highest importance, has been quite overloolted by the com- mentators upon him. One of the main views he was trying to urge was that until some system could be proposed which would give a means of quantitative estimation of the constituents of a mixture, no further progress would be made. He was asking, in fact, that chemistry should become an exact science, and his demand is only veiled by the unt'zuniIi- arity of his language. His preference for the “mechanical or corpuscu- larian" philosophy was mainly due to his realisation that, unlas chemistry was going to start mmsuring something, it might as well languish in the obscurity to which Harvey would willingly have rele- gated it. Thus he says,

But I should perchance forgive the Hypothesfi I have been all this time examining [that of the alchemist], if, though it reaches but to a very little part of the world, it did at least give us a satisfactory account of those things which ‘ti: said to teach. But I find not that it gives us any other than I very imperfect information even about znixt bodies themselves; for how will the knowledge of the T1172 Prirna‘ discover to In the ruson why the Loadstone drawes a Needle, and dispose: it to respect the Palm, and yetaeldom ;~m1u_ly pains at them? how will this hypothesis teach us how’: Chuck IS formed in the Egge, or how the seminal principles of mint, pompxons. and other .\eg_e~ tables, can fashion Water into various plants, ach of them cndt!W't.iV-V1lh.lYS peculiar and determinate shape and with divers specificlt and discmninattng Qualities? How does this hypothesis shew us, I-ow mu_ch Salt, how nnuh Sul- phur, how much Mercury must hetaken to make a Chxclt or

if We know that, what principle is it, that manages these ingredients and contrives, for instance, such liquors as the White and Yolke of an Egge into such a variety of textures as is requisite to fashion the Bones, Arteries, Veines, Nerves, Tendons, Feathers, Blood and other parts of a Chick; and not only to fashion each Litnbe, but to connect them altogether, after that manner which is most oongruous to the perfection of the Animal which is to consist of them? For to say that some more fine and subtile part of either or all the Hypostatical Principles is the Director in all the business and the Architect of all this elaborate structure, is to give one occasion to demand again, what proportion and may of mixture of the T113: Prirmz afforded this Architectonick Spirit, and what Agent made so skilful and happy a mixture?‘

‘ The salt. lulphnr and mercury of the nlchemim. r76 PLATE XV

Boyle's instance of the magnetic needle pointing nearly, not exactly, at the north, and his use of the expressions “how much", "how many", “proportion", “way of mixture,” indicate that he was moving towards a quantitative chemistry, and by obvious implication a quantitative embryology. Elsewhere he says that he thinks the Trio Piima will hardly explain a tenth part of the phenomena which the "Leucippian” or atomistic hypothesis is competent to deal with. Thus, although Boyle made few experiments or observations on embryos, he occupies a very important position in the history of embryology.

During the last two deoades of this century, the Oxford Philosophical Society was occupied on a good many occasions with problems relating to embryology. It is extremely interesting to note, in connection with what we have just seen in Boyle, that John Standard of Merton College reported on February xoth, 1685,

the following obbs. concerning y‘ weight of y‘ severall parts of Hem‘: eggs; done with a pair of scales which turned with § a grain.’

azr. :11. 1:7. gnu.

A henn’s egg weighed . . 2 — 1 15 The skin weighed . . . — — - 16 The shell . . . . - 2 2 4 The yolk . . . . - 5 I — The white . . . . 1 1 — 6

Loss in weighing . 9

Another early quantitative observation was that of Claude Perrault, who found about 1670 that incubated ostrich eggs lost one-ninth of their weight in five weeks.’ The Oxford Philosophical Society, however,

‘ Italics mine.

' The full appreciation of the balance I: u tool of ixzvutigation did not, of course. come until the second half of the eighteenth century, though Suclhufl’ has found in Pu-xcetxux 1 hmt of it.

' Illim, Hist. Nat. (1671), voL a, p. 133: (1676), vol. 2. P. 177. u.:.—tz 177 A msroar

preferred as a rule to consider more unusual things, such as "the egges of a parrot batched in a m>eman’s bosome, a hen egg figur’d like a bottle, a hen egg that at the big ende had :1 fleshie excrescence, mother hen-cg, monstrous, a suppos'd cocks egg, and the egs of a pufiin, an elhgug, and a razor-bill." Mention of these different kinds of eggs reminds us that the systematic collection and classifimtion of eggs had been begun some years before by Sir Thomas Browne (as may be seen In John Evelyn‘) and by John Tradesmnt. About this time R. Waller made some noteworthy observations on the "spawn of frogs and the production of Tadpoles therefrom," extending the work begun by Swzimmerdam not long before. Maurioeau now gave a description of the phenomenon of sterile foetal atrophy. The century fittingly closes with the treatises of Ettmfiller and Gibson, in which the embryologiral work of the seventeenth century is summarised with considerable accuracy. Ettmiiller supported the moribund menstruation theory of ernbryogeny with the argument that animals do not rnenstruate because they are more prolific than men, and therefore all their blood is required for generation.‘ Garmann’s Oolagia am'am, which appeared in 1691, is worth mention also, as a review of the knowledge of the time. But that his work was what the booksellers‘ catalogues describe as “cur-ious" is shown by the following chapter-headings "De ovo mystico, mythico, magico, mechanico, rnedico, spagyrico, magyrico, pharmaceutico.” Finally this was the time when embryonic monsters began to receive a really scientific description. We take an illustration (Plate XVI, facing page 178) from an unusual source, Robert Plot's Natural Hirtory cf Staflordslire (1686); it shows a teratuma with the well»formed teeth and hair so characteristic of such cystic growths. Dr Plot surmised that "dame Nature in this birth at first intended Twinns" but did not know “how she came thus to miscarry in her plastics."

I Diary, vol. 2, p. 69. - opera. 1:. no


A Itmlarna n-ilh Ixell-formed Imln and Imir Umm Robert Plot’: Nnur-I llmory of Snffoydshire, 1686).

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