Book - Anatomical and physiological studies on the growth of the inner ear of the albino rat (1923): Difference between revisions

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5 (zona arcuata) and 10, which is the radial breadth of the zona  
5 (zona arcuata) and 10, which is the radial breadth of the zona  
pectinata of the membrana basilaris.  
pectinata of the membrana basilaris.  
==I. On the Growth of the Cochlea==
As noted above, I have selected from at least seven serially
sectioned cochleas in each age group, four for this study, taking
one section in good condition from each labyrinth. From these
four sections the average values were taken for each age. Table 1
gives the data for the rats used here. As we see, sometimes two,
sometimes three animals were used at each age to get the four
best-prepared sections which corresponded. Determinations
accordingly to sex and side, therefore, cannot be based on like
numbers.
In the following text we shall often refer to the I, II, III and
IV turns of the cochlea. This calls for a word of explanation.
As the cochlea of the rat has nearly 2^ complete turns, four
cochlear canals are usually obtained in the radial vertical sections,
as prepared by me (fig. 3). Therefore, turn I does not mean the
first complete turn, but about the middle part of the basal
turn; turn II about the beginning of the middle turn; turn III
about the middle part of the middle turn, and turn IV about the
beginning of the apical turn of the cochlea. Usually the cochlea
has been divided for description by the authors into the first,
second, and third turns, or more definitely into the basal, middle,
and apical turns. For the purpose of this study, however, it
is desirable to adopt the divisions given above, because here
measurements are largely employed, and there are some differences in size, volume, and arrangement of structures, even between
the beginning and end of the same turn.
At all events, it is to be kept in mind that such divisions are
arbitrary, as the changes in the elements take place in a graded
manner.
A. On the growth of the radial distance between the two
spiral ligaments (fig. 3, 1-1, 2-2)
As we have usually four sections of the ductus cochlearis,
therefore four spiral ligaments in one radial vertical section,
there are two radial distances presented, the first, figure 3, 1-1,
connecting the two basal sections of the ductus on opposite
sides, and the second, figure 3, 2-2, connecting the two apical
TABLE 1
Data on the albino rats used for the study of the cochlea
AGE
BODY WEIGHT
BOOT LENGTH
BEX
SIDE
HEARING
days
grams
mm.
1
5.3
48
d"
R. L.
1
4.2
47
o"
R. L.
3
8.8
60
a"
R.
3
7.1
54
o"
R. L.
3
8.2
56
9
R.
6
10.2
64
9
R. L.
6
11.0
62
tf
R. L.
9
9.1
58
9
R. L.
9
9.8
57
tf
R. L.
=fc
12
13.0
70
a 1
L.
+
12
11.9
68
9
R. L.
+
12
14.8
72
d"
L.
+
15
13.0
74
0"
R.
+
15
13.5
75
9
R.
+
15
13.0
74
9
R. L.
+
20
30.0
96
cf
R. L.
+
20
28.0
94
c?
R. L.
+
25
38.4
107
9
R. L.
+
25
34.2
101
9
R. L.
+
50
60.0
128
9
R. L.
+
50
57.5
121
9
R. L.
+
100
145.6
176
a 1
L.
+
100
102.5
154
9
R.
+
100
100.5
152
9
R. L.
+
150
153.5
184
9
R.
+
150
188.9
191
d 1
R. L.
+
150
198.8
192
<?
R.
+
250
133.5
178
9
R. L.
+
263
140.3
171
9
R. L.
+
365
205.4
202
0"
L.
+
365
170.4
182
9
R. L.
+
368
179.0
196
9
R.
+
546
282.1
222
<?
R. L.
+
546
227.1
204
rf
R. L.
+
sections. These distances measure the radial breadth of the
membranous cochlea and of the modiolus combined at these levels.
In table 2 (chart 1) are entered the values for the radial
distances found between the two spiral ligaments in fourteen
TABLE 2
Radial distance between the two spiral ligaments in radial-vertical section
(chart 1, figure 3)
AVERAGE DISTANCE BETWEEN TURNS IN M
AGE
TTTT'nWP
I-II
III-IV
I-II plus III-IV
days
grams
mean
1
5
1410
925
1168
3
8
1560
1025
1S93
6
11
1650
1175
1413
9
10
1635
1225
1430
12
13
1640
1233
1437
15
13
1655
1235
1445
20
29
1645
1250
1448
25
36
1620
1250
1435
50
59
1615
1253
1434
100
112
1663
1270
1467
150
183
1618
1290
1454
257
137
1655
1275
1465
366
181
1635
1285
1460
546
255
1680
1265
1473
Ratios 1 12 days 1 1.2
1 20 " 1.2
1 546 " 1.3
TABLE 3 Condensed
Ratios of distances between the two spiral ligaments along 1-1 (turns I-II) and
along 2-2 (turns III-IV), figure 3
AGE
BODY WEIGHT
Ratios between the two distances
turns I-II and III-IV
days
grams
1
5
. 1:0.66
8
11
:0.72
18
21
:0.75
213
138
:0.77
age groups, from one to 546 days. As we see, the average value
of the two distances grows rapidly from birth till six days of
age. After that period the value increases gradually till twenty
days, while after twenty days the increase is very slight indeed.
The ratios between 1 and 12, 1 and 20, and 1 and 546 days show
these relations.
In table 3 are given the average ratios between two radial
distances between I-II and III-IV at four ages. Here we can also
see a rapid increase in the ratio from one to eight days of age,
while afterwards the ratios rise very gradually. The data in
table 2 show that at nine days the mean diameter of the bony
cochlea as thus measured is approximately 97 per cent of the
value at maturity. The cochlea thus attains nearly its full size
at an early age. Chart 1 illustrates this point.
Chart 1 The radial distance between the spiral ligaments, turns I-II and
III-IV, table 2, figure 3 (/-/) and (-).
Radial distance at turns I-II.
Radial distance at turns III-IV.
Average radial distance for the two foregoing measurements.
All the charts are plotted on age.
The scale for age changes at 50 days. From to 50 days one interval is
equal to five days. From 50 days on, one interval is equal to twenty-five days.
Unless otherwise stated, the measurements recorded in these charts have
been made on radial-vertical sections.
B. On the growth of the tympanic wall of the ductus cochkaris
Figures 4 to 12 show the appearance in outline at birth, at
three six, nine (not hearing), nine (hearing), twelve, twenty one
hundred, and 546 days, respectively. These figures have been
drawn from the best corresponding sections at the beginning
of the middle turn of the cochlea, figure 3, turn n, which I have
selected as the type, as did Retzius.
The fact, demonstrated by many authors, Bottcher ('69),
Retzius ('84), and others, that development progresses from
the basal to the apical turn is confirmed in the albino rat.
In the albino rat the development of the cochlea, and especially of the ductus cochlearis, is somewhat retarded as compared
with man, and the papilla with its elements developed in a great
measure during the first ten days after birth.
As we see in figure 4, the ductus cochlearis in the new-born
rat is very immature. It is remarkable that the space which
lies in adult rats axialward of the papilla spiralis between the
membrana tectoria and the limbus spiralis-sulcus spiralis internus
(fig. 10) is not yet to be seen. Instead of the space, there is the socalled greater epithelial ridge (der grosse Epithelwulst of Bottcher)
figure 4, G. consisting of pseudostratified epithelial cells. These
long and narrow cells lie pressed very closely together with
their large oval nuclei at various heights. The surface of the
prominence sinks slightly in its center, and at the outer end of
the prominence more rapidly, where it passes over into the socalled lesser epithelial ridge fig. 4, L. (der kleine Epithelwulst)
at an obtuse angle.
The latter is, of course, a relatively small prominence, making
up the greater part of the papilla spiralis. The pillar cells of
Corti lie with their upper ends at the most inner part of the
surface of the lesser ridge just in the angle with the greater
ridge. They form two entirely separate rows of cells, the inner
and the outer, but so close together that we cannot detect any
space between them. Only the protoplasm of the inner pillar
cell is more transparent above the nucleus, and on the inward
side there is a thin rod passing from the upper end to the lower part near the base. This transparent area is not the locus of
the future tunnel of Corti, but marks the protoplasmic change
into the pillar, as the transparent substance condenses into the
rod. We can see this change beginning in the basal turn before
it appears in the apical turn of the cochlea. The inner and
outer cells make a triangle with a narrow base, which clings to
the membranea basilaris; they turn somewhat outward. 1
A large oval nucleus lies in the basal part of each cell; that of
the inner pillar cell is very large, about twice as large as that
of the outer, and with its long axis in a radial direction. As
figure 4 shows, the inner corner of the inner pillar cell does not
yet reach to the habenula perforata.
The hair cells, which in the albino rat are in four rows through
all the turns, are separated by the pillar cells into two groups,
the inner containing one and the outer three rows of cells. They
are comparatively well developed at birth (fig. 4). The inner
hair cell belongs to the greater ridge, as Kolliker ('67), Gottstein
(72), Retzius ('84), Held ('09), and others have already affirmed,
and contrary to the assertaion of Bottcher ('69) and others.
It is situated in the most outer part of the declivity of the
greater ridge and slants away from the axis with its round lower
end at about half the height of the greater thickening. It has
a large round nucleus in the base and the small hairlet at the top.
This hair cell is nearly twice as large as the outer hair cells.
The three outer hair cells reach down to the middle of the lesser
ridge, not through it, having no process at their basal end.
They end with their upper parts at the surface of the prominence.
They stand not straight, but turn with their long axis very
slightly inward, i.e., the in direction opposite to the long axis
of the inner hair cells. They are cylindrical in form with a round
nucleus at their base and small hairlet on the top.
Below the outer hair cells stand the three rows of Deiters'
cells, which have large oval nuclei. These rest with their wide
bases on the basilar membrane and their pointed ends reach
to the surface of the epithelium. They are retarded in development, and at birth their cell bodies are short and undeveloped,
so that they hardly suggest the adult cells.
* 1 In the following description of the cochlea, 'outward' means away from the axis 'inward' towards the axis.
Hensen's supporting cells (fig. 10, at maturity) are as yet
undeveloped and nearly uniform in height, their nuclei being
at nearly the same level.
Outward from the Hensen's cells the height of the epithelial
cells at maturity rapidly diminishes and passes over to the
cylindrical cells of sulcus spiralis externus. At birth no such
distinction is present. Through all the turns the surface of the
lesser epithelial ridge remains about parallel to the plane of the
membrana basilaris.
The membrana basilaris, which stretches from the labium
tympanicum outward to the crista basilaris of the ligamentum
Figs. 4 to 12 Showing the increase in size and morphological changes in
each part of the tympanic wall of ductus cochlearis of the cochlea during
growth, in the radial vertical section albino rat. All the figures have been
uniformly enlarged.
Fig. 4 One day. C, greater epithelial ridge; L, lesser epithelial ridge.
Fig. 5 Three days.
Fig. 6 Six days.
Figs. 7 to 8 Showing the differences in size and morphological changes in
the tympanic wall of ductus cochlearis between a nine-day-old rat which can
already hear (fig. 8) and one that cannot (fig. 7)
Fig. 9 Twelve days.
Fig. 10 Twenty days. In figure 10 we have drawn all the elements of the
organ.
ABBREVIATIONS
M.T., membraua tectoria a. Corti O.P., outer pillar
L.V., labium vestibulare of crista B.C., basal cells
spiralis D.C., Deiters' cells
S.S.I., sulcus spiralis interims Bo.C., Boettcher's cells
S.I.C., cells of sulcus spiralis interims L.S., ligamentum spirale
I.S., inner supporting cells N.F., myelinated fibers of ramus
I.H., inner hair cells acustici
O.H., outer hair cells R.F., radial fibers of ramus basilaris
H.S., Hensen's supporting cells acustici in the tunnel of Corti
S.E.C., cells of sulcus spiralis externus T., tunnel of Corti
M.B., membrana basilaris B., blood vessels
I. P., inner pillar 0., bone
Fig. 1 1 One hundred days.
Fig. 12 546 days.
GROWTH OF THE INNER EAR OF ALBINO RAT
21
HS
22
spirale, consists of two layers, an upper, membrana basilaris
propria, and an under, tympanic investing layer (tympanale
Belegschicht : Retzius). The former, of course, is divided into
two portions, an inner, zona arcuata (Deiters) and an outer,
zona pectinata (Todd-Bowman). While the zona arcuata is
thin from the beginning of life, the zona pectinata thickens at
its central part where it contains cells with oblong nuclei. On
passing to the spiral ligament it again becomes thin. In the
young, the under layer is not so regular in structure as in the
adult. The *cells close to the basilaris propria are arranged
vertically.
On the contrary the cells below them, which vanish in great
part with age, have an irregular arrangement; those near the
endothelial cells of scala tympani having a more radial arrangement. Therefore, this layer is thick, several times the thickness
of the basilaris propria, and the thickness increases towards
the upper turns. The vas spirale is strikingly large at this stage
and lies just under the outer pillar and the Dieters' cells.
The membrana tectoria, beginning at the inner angle of the
ductus cochlearis, where Reissner's membrane rises, covers the
epithelium of the limbus laminae spiralis and the greater epithelial
ridge, lying close to their surfaces. At the inner part it is thin,
but thickens where the greater ridge begins, and at the outer
part again becomes thin. In the basal turn there is seen as a very
thin strand reaching to Hensen's prominence, but in the apical
turn it reaches hardly to the inner hair cell. Although it gives
rise to several thread-like processes going to the surface of the
papilla, these do not seem to connect with the hairs of the hair
cells, but with the terminal plates of the Dieters' cells.
When we divide the tympanic wall of the ductus cochlearis at
the boundary between the greater and lesser epithelial ridges,
we observe that the inner portion from the inner angle to the
outer end of the greater ridge is far larger than the outer portion,
which, however, is the more important for hearing. This
relation becomes more evident as we pass from the base to the
apex. Moreover, the total radial length of the tympanic wall diminishes at this stage towards the apex, though it is larger
in the beginning of the middle turn than in the middle of the
basal turn. As will be shown later, these relations are entirely
reversed in the adult cochlea. This fact indicates that the
cochlea at this stage is very immature.
In the three-day-old rat the cochlea is much better developed
(fig. 5). The radial breadth of the typmanic wall of the ductus
cochlearis becomes greater in all the turns, especially in the upper
turn; therefore the differences between the radial breadths in
each successive turn are smaller than at the earlier stage. There
is some change as we pass towards the apex in the relation of
the inner and outer portion of the tympanic wall. At the basal
turn and the beginning of the middle turn the radial breadth
of the outer portion increases greatly, but diminishes again
towards the apex. Although the radial breadth of the inner
portion increases through all the turns, the proportion of this
increase becomes greater towards the apex. As the inner portion
is composed of the greater epithelial ridge and of the limbus
laminae spiralis, and as the breadth of the latter diminishes
towards the apex, the increase of the radial breadth of the inner
portion is due to changes in the greater epithelial ridge.
The heights of the greater epithelial ridge, however, diminishes
through the successive turns, becoming less and less from base
to apex. Thus in the cochlea at this age it has a small radial
breadth and vertical height in the basal turn and a larger radial
breadth and height in the upper turns.
In all the turns the inner hair cell is inclined outwards and
lies with its surface forming the outermost part of the greater
ridge. The obtuse angle which it helps to make (fig. 5) as a
boundary between the greater and lesser ridge in upper turns,
vanishes in the basal turn where there is no sharp boundary
between the two ridges.
The pillar cells of Corti develop more and more during this
early stage; the radial breadth of their base increases, but as
yet there is no space between them. They incline much more
outwards than in the earlier stage. The protoplasmic change
in the rod progresses, especially in the basal turn, and the head
plate of the cell can be seen distinctly.
The outer hair cells become higher and wider; they are slightly
inclined inward in the upper turn. On passing towards the
basal turn the inclination inward increases, and in the basal
turn it is most oblique, almost at 45, to the plane of the basilar
membrane. In figure 4 the inclination of these cells is only
slight.
Deiters' and Hensen's cells are not well developed; the conditions are as in the former stage.
The plane of the surface of the lesser epithelial ridge is intimately related to the development of the outer hair cells and
Deiters' cells, and as the latter are in an undeveloped condition,
it runs nearly parallel to the plane of the membrana basilaris,
sometimes dipping outward.
The membrana basilaris seems to be much longer; its composition is about the same as that in the one-day rat, only the
thickness is somewhat decreased, owing to the reduction of the
rows of cells in the tympanic layer.
The membrana tectoria grows in breadth and thickness,
covering very closely the inner portion of the tympanic wall
and connects outwards with Deiters' and Hensen's cells by
slender fibrous processes the so-called outer marginal zone.
The hairs of the cells stand between these processes, but have
no connection with them.
The vas spirale does not suffer reduction.
At six days (fig. 6) the development of the cochlea has proceeded futher. The radial breadth of the tympanic wall has
increased. Thus we find the tympanic wall, especially its inner
portion, increasing towards the apex, chiefly owing to the augmentation of the radial breadth of the greater ridge. In this a
remarkable change is to be seen. In the basal turn the long
slender cells disappear in the inner part of the greater ridge,
and instead of them there are found cylindrical cells with oval
nuclei near their bases.
The height of these cells increases gradually to the level of the
surface of the inner hah- cell; their upper surface is here in contact
with the membrana tectoria. Thus a space appears between
the cylindrical epithelium and the membrane the sulcus spiralis interims which is deep and wide in the basal turn,
becomes gradually shallow and narrow as we pass upward, and
in the middle part of the middle turn is to be seen as a small
and flat space. In the apical turn it is not yet present. The
inner side of this space is made by the labium vestibulare of
the limbus laminae spiralis.
As a result of this change in the greater ridge, the obtuse angle
between the greater and lesser ridge vanishes entirely, and the
two surfaces come to lie in the same place. The inner hair cell
becomes larger and inclines less outward.
It is to be noted that the inner hair cell is supported on both
sides by long slender cells. These have been variously described
by several authors, but first Hans Held ('02) and afterwards
Kolmer ('07) have considered them as supporting cells, reaching
from the surface of the hair cell to the plane of the basilar
membrane. Held has termed the cell which lies outward the
' Phalangenzelle. '
I have paid some attention to this cell and the changes in it.
It is long and slender and stands between the inner hair cell
and the inner pillar cell, with the upper end reaching to the
surface, and is attached at its base to the inner corner of the
inner pillar. The oblong oval nucleus lies in its basal portion.
On the inner side of the inner hair cell there is a group of two to
three cells of the same kind. These cells, termed ' Grenzzellen '
by Held, stand near the habenula perforata, reach to the height
of epithelium, and have their bases in intimate relation to the
former.
These are not neuro-epithelial cells nor in intimate relation with
the nerve fibers, but similar to the Deiters' cells which support
the outer hair cells.
The developing pillar cells become progressively wider at their
bases. The inner pillar cell sends a long foot towards the habenula
perforata and in the basal turn it sometines reaches to it. The
outer pillar cell increases its length very rapidly and extends
its foot outward on the basilar membrane. Thus in the basal
turn the triangle made by the inner and outer pillar cells and
having a short base, in the upper turns changes to an equilateral triangle and stands upright on the basilar membrane. In the
apical turn the inner pillar cell is not yet so long as in the lower,
turns and is still inclined outwards. The head plates and pillars
are fairly prominent, but there is as yet no space between them.
The outer hair cells have grown and are inclined inward.
Deiters' and Hensen's cells have not yet begun to develop, as
have the other elements of the organ of Corti just described.
In the membrana basilaris we see the reduction of cells in
the tympanic covering layer. The vas spirale shows more or
less reduction. The membrana tectoria increases its radial breadth
following the associated structures. The so-called marginal zone
connects with Hensen's cells and the lamina reticularis by
fibrous processes.
Among five nine-day-old rats, as shown later, one responded
to the tests for hearing. As the majority of them gave no reaction, the cochlea of the latter, non-hearing rat, may be taken
as the type for this age. The differences between the cochlea
of the hearing and non-hearing rats will be mentioned later.
In rats of this age (fig. 7.) the cochlea is still further advanced.
The sulcus spiralis internus appears through all the coils, and is
deepest and broadest in the basal turn, diminishing in depth
or gradually toward the apex. The cells covering the space are
low and cuboid in the lower turns, but in the apical turn they are
yet relatively high, cylindrical cells.
These cells probably have their origin from the long slender
cells of the greater epithelial ridge, as Bottcher ('69) and others
maintain, although Gottstein (72) and some others think that
they come by the outward migration of the epithelium of the
limbus spiralis, and Retzius ('84) regards this latter view as the
more probable.
The inner and outer hair cells become large and approach
their mature form. The supporting cells of the inner hair cell
are very evident.
The pillar cells develop more and more, their radial breadth
increases and the pillars and headplates also become distinct.
Sometimes we see a small space between the inner and outer
pillar cells in the lower turn, but not in the upper. Nuel 's space is not yet to be seen. Deiters' cells become longer, somewhat
in the processus phalangeus but chiefly in the cell body, and the
nuclei move upward. Hensen's cells also increase in height
slightly.
While the membrana tectoria lies close to the surface of the
outer part of the greater ridge in the upper turns of the cochlea,
there arises a small space between them, which is continuous with
the sulcus spiralis internus. The outer marginal zone of the
membrane is still connected with Hensen's supporting cells and
the lamina reticularis. The vas spirale remains as a large vessel.
This is the condition of the nine-day cochlea in a rat which does
not hear.
Although the detailed description of the cochlea of the nineday rat which can hear will be deferred for a time, yet to complete
the series of growth changes, figure 8, representing the cochlea
in such a rat, is inserted here.
In the next stage, twelve days old (fig. 9), the development of
the tympanic wall is much advanced. The cells lining the sulcus
spiralis internus and the-inner supporting cells have nearly their
mature form and arrangement in the basal and middle turns;
only in the apical turn many and slender cells remain close to
the inner hair cell.
The outer pillar cell shows a remarkable increase in length so
that it is twice as long as in the former stage, while the growth
of the inner pillar is much less marked.
Therefore the outer pillar is much longer than the inner
through all the turns. From this change in the pillar cells it
results that the nearly equilateral triangle formed by them
becomes unequal and its summit is shifted inward. In all the
turns we can see the tunnel of Corti and also the space of Nuel.
The hair cells develop further and their previous inclinations are
increased.
Deiters' cells show a very rapid development, especially in
the cell body, which increases many times, the nucleus moving
upwards. The inclination of these cells follows that of the
outer hair cells.
Hensen's supporting cells are also fully developed. Through
the development of Deiters' and Hensen's cells a change is
effected in the course of the lamina reticularis. It runs no longer
parallel to the plane of the membrana basilaris, but dips inward.
Though the membrana basilaris remains nearly stationary in
its breadth, the thickness of the tympanic covering layer is
reduced and the longitudinal nuclei in the zona pectinata diminish
in number.
The membrana tectoria reaches in the basal turn to the outermost row of the outer hair cells, but the apical turn only to the
second row. The so-called 'outer marginal zone' connects with
the terminal frame (Schlussrahmen) of the lamina reticularis.
In the next stage, the twenty-day-old rat (fig. 10), the papilla
spiralis and the tissues about it are developed almost completely; therefore, the structural relations of the cochlea accord
nearly with those of the adult cochlea, as generally recognized
in histology.
It is to be noted here that in the basal turn, Bottcher's cells
are to be seen in sulcus spiralis externus* as a cell group situated
on the outer part of the vestibular surface of the membrana
basilaris. This cell group consists of several granular compact
and sharply bounded cells entirely covered by high swollen cells
on all sides. That this cell group belongs to the epithelium of
the sulcus spiralis externus can be easily demonstrated. While
the cells in this group show no particular changes in structure,
the neighboring cells diminish in their height and size towards
the apex, and finally become similar to the former. After twenty
days of age the general features of the cochlea are those of the
adult and do not require general description. The finer differences will be discussed in subsequent chapters.
Figure 11 shows the relations at 100 days and figure 12 at
546 days.
1. Membrana tectoria. As stated above, this membrane is
divided into two zones, an outer and inner, using the outer edge
of the labium vestibulare as the point of division (fig. 1, 7-7').
Each zone was again divided into two equal parts at 6-6'and8-8'.
Thus the sum of the breadths of the two outer parts represents in each instance the breadth of the outer zone, and the sum of
the two inner parts that of the inner zone, while the sum of all
four parts gives the total radial breadth. For the purpose of the
exact measurement of the growth of the membrane, I have,
as noted above, projected the sections at 100 diameters and made
the determinations on the outlines thus obtained.
In table 4 (charts 2 and 3) are given the values for the total
average breadth, as well as for that of each zone, and also the
thickness of the membrane, from 1 to 546 days of age. At the
bottom of each column are given the ratios of the breadth at
1 to 546, 12 to 546, and 20 to 546 days. While the ratio between
1 and 546 days is 1.7, those from 12 to 546 days and 20 to 546
days diminish to about 1:1.0, that is the membrane at twelve
days has attained about its full breadth, and there is only a
very gradual increase in its breadth with advancing age. After
twelve days similar ratios are found for the separate zones as
well.
From 1 to 546 days the ratios for the two zones differ considerably; that for the second zone is 1:1.2 and that for the
first is 1:3.6. This is due to the fact that in the cochlea at birth
the development of the labium vestibulare is incomplete, even
in the basal turn, while at the apex we can very often hardly
see the invasion of the mesenchymal tissue in the inner part of
the greater epithelial ridge.
At every stage the outer zone is broader than the inner; the
ratio between them at birth is 1:3.8. This diminishes to 1:1.25
at twelve days, after which age it remains practically constant.
Owing to the form of the membrana tectoria and to its great
sensitiveness to the method of preparation, it is difficult to
obtain good values for its thickness.
Generally speaking, the membrane is thickest about midway
between the outer edge of the labium vestibulare and the inner
boundary of the inner hair cell, and it was here the measurements
given in table 4 were made. As shown in this table, the thickness
increases rather rapidly from birth to twenty days, but after
that period remains approximately constant.
As we know, the radial breadth of the membrane increases
gradually from the basal to the apical turn. Table 5 (charts 4,
5, and 6) shows how the breadth of the total and of each part
of the membrane changes in successive turns from base to apex
according to age. At birth it is broadest in the beginning of the
middle turn (turn II) decreasing gradually towards the apex.
From three to twenty days the greatest breadth is usually found
TABLE 4
Average radial breadth of the membrana tectoria and its thickness in radial-vertical
section. Averages of all four turns (charts 2 and 8)
AGE
BODT
WEIGHT
BODY
LENGTH
Outer zone
between free
end of membrane and
labium
Inner zone
labium
vestibulare
and insertion of membrane
Total length
of membrane
Ratios
inner and
outer zone
Thickness
membrane
days
grams
mm.
M
M
M
M
1
5
48
140
37
177
1 3.78
12
3
8
56
134
94
228
. 1.43
32
6
11
63
154
105
259
1.44
32
9
10
58
158
123
281
1.28
27
12
13
60
157
126
283
1.25
25
15
13
75
160
124
284
1.29
28
20
29
95
162
129
291
1.26
38
25
36
104
162
128
290
1.27
34
50
59
125
162
131
293
1.24
35
100
112
159
162
132
294
1.23
36
150
183
190
161
131
292
1.23
32
257
137
175
163
129
292
1.26
38
366
181
191
162
131
293
1.24
35
546
255
213
163
132
295
1.23
34
Ratios 1 546 days
1 1.2
1 3.6
1 1.7
1 2.8
t 12 546 "
1.0
1.0
1.0
1.4
20 5 "
1.0
1.0
1.0
0.9
in turn III, but after this in turn IV. At the bottom of each
column are given the ratios of the radial breadth in each turn
between the several age limits.
These show that after twelve days there is but little change
in the radial breadth of the entire membrane in any turn.
On examining the growth in each zone of the membrane
through the several turns, we find that after three days the outer
zone of the membrane becomes at each age always broader
from base to apex.
31
u
200
150
100
50
o
AGE QAYSH
i i
O
25
50
5O 10O 2OO 3OO 4OO 50O
Chart 2 The radial breadth of membrana tectoria, table 4, figure 1.
Total radial breadth of the membrane.
Radial breadth of outer zone.
*- Radial breadth of inner zone.
25 50 50 10O 2OO 3OO 4OO 5OO
Chart 3 The thickness of membrana tectoria, table 4.
32
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
ta o
i
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BS
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W i i
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20-546
GBOWTH OF THE INNER EAR OF ALBINO RAT
33
The values at birth are relatively greater than those at three
days, as noted above, due to the undevelopment of the labium
vestibulare. The inner zone grows in a like manner in breadth,
but not so rapidly as the outer zone, and hence its relative breadth
diminishes gradually from base to apex.
Table 6 shows these relations. While the ratios in the inner
zone decreases from base to apex, those in the outer zone increase.
Thus the ratios in the inner and outer zones according to the
turns go in opposite directions. As stated above, the radial
breadth is generally larger in the outer zone, but this relation
is, in general, reversed in turn I, table 5.
TABLE 6 Condensed
Ratios of the radial breadth of each zone of the membrana tectoria
Ratios according to turns of the cochlea
Ratios between inner and
BOOT
INNER CONE
OUTER ZONE
outer zone
AGE
__ fjfi**T
Turns
Turns
Turns
I-II
I-III
I-IV
I-II
I-II I
I-IV
I
II
in
IV
days
grams
1
5
1:0.8
1:0.5
1:0.0
1:1.2
1:1.3
1:1.4
1:1.8
1:2.8
1:4.3
1:0.0
8
11
:0.9
:0.9
:0.8
:1.4
:1.8
:1.9
:0.8
:1.2
:1.6
:2.0
18
21
:0.9
:0.9
:0.8
:1.4
:1.8
:2.0
:0.8
:1.1
:1.5
:1.9
203
160
:0.9
:0.9
:0.8
:1.4
:1.7
:2.0
:0.8
:1.1
:1.5
:1.8
In turn I the average ratios are, after eight days, smaller than
1.0; therefore, the inner zone is wider than the outer in turn I.
It increases in all ages from turn II toward the apex.
In table 7 are given the ratios between each turn of the cochlea.
The ratios after nine days of age are practically constant according
to age, but those between turns I and II are always smaller
than the others; the ratios for the two latter being alike. The
ratio at one day is, however, an exception, as stated already.
As the measurements show, the membrana tectoria is at birth
relatively undeveloped; it is thin and immature. After birth
it increases rapidly during the first nine days, a statement which
applies generally to the postnatal growth of the organs of the
albino rat. Thus we get a ratio of the radial breadth 1 :1 .7 between
1 and 546 days, but after twelve days the ratios remain practically 1:1.0. (Table 4.)
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
It is not my purpose to describe the fetal development of
the membrana tectoria, but it is worth while to consider briefly
the zones which compose the membrane; in other words, the parts
of the tympanic wall from which it originated. There are chiefly
TABLE 7
Ratios of the radial breadth of the membrana tectoria according to the turns of the
cochlea
AGE
BODY WEIGHT
Ratios according to turn of the cochlea
I-II
I-II I
I-IV
days
gms.
1
5
1 1.0
1 1.0
1 :0.9
3
8
1.2
1.2
:1.2
6
11
1.2
1.4
:1.3
9
10
1.1
1.3
:1.3
12
13
1.1
1.3
:1.3
15
13
1.1
1.3
:1.3
20
29
1.1
1.3
:1.3
25
36
1.1
1.3
:1.4
50
59
1.1
1.3
: 1.3
100
112
1.1
1.3
:1.4
150
183
1.1
1.3
: 1.3
257
137
1.1
1.3
:1.3
366
181
1.1
1.3
:1.3
546
255
1.1
1.3
:1.3
Chart 4 The total radial breadth of membrana tectoria arranged according
to the turns of the cochlea, table 5.
About middle part of the basal turn (I).
About the beginning of the middle turn (II).
About the middle part of the middle turn (III).
About the beginning of the apical turn (IV). 2
Chart 5 The radial breadth of the inner zone of the membrana tectoria,
according to the turns of the cochlea, table 5.
Chart 6 The radial breadth of the outer zone of the membrana tectoria,
according to the turns of the cochlea, table 5.
* In most cases when the values which have been determined are analyzed
according to the turns of the cochlea, it is found that they increase with later
growth from the basal (I) to the apical (IV) turn and in the order just given in
chart 4. Owing to this uniformity of behavior, some thirteen charts showing
the several values according to turn have been omitted, since the graph given
by the average value is sufficiently informing in each instance.
In the case of those charts which have been retained, and in which the
measurements are according to the turns of the cochlea, the respective turns
I-IV are recorded by characteristic lines similar to those used for them in
chart 4, and in these cases the further designations of the turns are omitted.
350
300
I
ISO
G.E DAYSH
25 5O
50 1OO 2OO 30O 400 500
Chart 4
150
1OO
50
AGE
25 50 50 1OO 200 300 4OO 500
Charts
180
100
DAYS
25 50 5Q 1OO 2OO 3OO 4OO 5OO
Chart 6
36
two views about this. While a few authors, Kolliker ('67),
Hensen ('63), and recently Hardesty ('08, '15), and others hold
that only the greater epithelial ridge takes part in the formation
of the membrane, most investigators (for example, Bottcher,
'69; Retzius, '84; Rickenbacher, '01; Held, '09; Van der Stricht,
'18) consider that it originates from both the greater and lesser
epithelial ridge. My figure 5, supports the latter view; that is,
while the main part is developed from the greater ridge, the
outer narrow marginal part is secreted from the lesser ridge.
The figure in Quain's Anatomy by Schafer ('09) (vol. 3, part
2, p. 332, llth ed.,) is from the earlier paper of Hardesty and
shows the membrane in the pig as arising from the greater
epithelial ridge only.
Hardesty has corrected this figure in his paper published in
1915. Thus in the very early stage after birth in these forms
we have three zones, an inner, an outer, and a marginal zone.
With age, however, this marginal zone becomes, as Held ('09)
and others agree, gradually smaller and smaller, and finally
it is difficult to differentiate it from the outer zone. Thus for
convenience in measurements I have treated the membrane as
consisting of two zones only.
Comparing the breadth of the inner and outer zones, it is
evident that the outer is always the broader. The ratio is
(table 4) at birth 1 : 3.78, at three days 1 : 1.43, and then gradually
diminishes to 1:1.23 with age.
Now if we examine the ratios of the total breadth of the
membrane according to the turns of the cochlea, we find after
six days that the ratio generally increases from base to apex,
and that these ratios remain nearly constant after nine days
of age, as shown in table 7.
Thus the ratio between turns I and II is 1:1.1; between turns
I and III, 1:1.3; between turns I and IV, 1:1.3. The breadth
of the membrane increases, -therefore, in the albino rat gradually
from the base to the middle part of the middle turn; from this
point it does not increase to the apex.
Since the breadth at the tip of the apex diminishes greatly,
as is generally recognized, Hardesty ('08) found in the pig the
following ratios (table 8):
GROWTH OF THE INNER EAR OF ALBINO RAT
37
Comparing these ratios obtained by Hardesty in the pig with
mine, there appear to be large differences between them. The
reason for these I will discuss later.
When we consider the breadth in each part of the membrane
according to the turn, we find that the increase of the breadth
of the membrane in each turn is due to the development of the
outer zone. The inner zone, which is adherent to the labium
vestibulare, does not increase in the rat as Hardesty ('08/15)
found to be the case for the pig, but on the contrary decreases
from base to apex a relation found by Retzius ('84) in the rabbit,
cat, and man and confirmed by Rickenbacker ('01) in the guineapig. On the contrary, the outer zone increases in breadth from
TABLE 8
Ratios of the breadth of the membrana tectoria according to turn of cochlea (Hardesty)
Kind of animal
Preparation
method
Ratios between
breadth in 7 and
5 half turn
Ratios between
7 and 3 half turn
Ratios between
7 and 1 half turn
Pigs two weeks
of age
Membrane
teased out
Membrane
1 : 1.4
1 :1.7
1 :2.5
teased out
1 :1.8
1 :2.5
1 :2.7
Adult
Membrane in
section
1 : 1.6
1 :2.1
1 :1.8
base to apex, and in each stage the ratios between the successive
turns are nearly the same. These ratios between successive
turns, however, show rather large differences according to the
different authors.
My results (table 5) show that the outer zone in the albino rat
is nearly two times wider at the apex than at the base. This
agrees with what von Ebner ('02) finds in the human cochlea.
When we consider the thickness of the membrane, we find
it thin at birth, but at three days (table 4) it increases rapidly
and reaches almost its greatest thickness. This increase in
thickness arises through the apposition of new layers to the
under surface, as Hasse (73) and others have noted, but very
large differences appear between the figures given by various
authors.
38 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
Kolliker ('67) finds the membrane 45 n thick in the ox. In
the guinea-pig it is 15 ^ in the thickest place, according to
Schwalbe ('87). Middendorp ('67) gets in mammals generally
a very thin membrane, about 1 n thick. Retzius ('84) states
that in the thickest part in the rabbit it measures 27 [x, in the
cat 32 to 50 |x, and in man 24 to 25 [x. Hardesty finds in the
young pig an average thickness of the teased membrane of
50 [x and in an adult hog 119.3 (x. I get 35 (x as an average in
the adult albino rat after twenty days of age, varying from 32
to 38 [x. My result is therefore closest to that for the cat as
obtained by Retzius. These results are plainly influenced b.y
the dissimilar technical methods used by the several investigators.
About the outermost end of the membrane there are still two
different views. One view is that the outer end of the membrane
projects beyond Hensen's prominence; Kolmer ('07; pig, calf
goat and horse); Hardesty ('15; pig, hog) Shambaugh ('10; pig).
Others assert that the membrane terminates with its outer edge
at the outer boundary of the outermost series of the outer hair
cells. My preparations show that in the rat the outer end of
the membrane does not reach Hensen's prominence.
Possibly this difference is due to the technique of preparation.
In the figures drawn by many authors we can recognize many
artifacts and postmortem changes in the cochlea. Even in the
figures of Kolmer ('07) we see these changes, although he injected
the fixing solution through the carotid artery. Held ('09) says
in his criticism of Hardesty 's figures that " figures 6 and 7 wie
schon Hardesty selbst vermutet hat, sicherlich auf einer Verquellung beruhen "
I myself never observed such a gigantic membrane as Hardesty
('08, '15), Shambaugh ('10), and others show in the cochlea
of the pig. On the other hand, I cannot absolutely deny that
there may have been shrinkage in the cochleas prepared by my
methods, though I see no evidence of it.
From our present knowledge, however, the method of vital
fixing is considered the best available, as already maintained by
Siebenmann and Yoshii ('08), Metzner and Yoshii ('09), Nager
and Yoshii ('10), Wittmaack and Laurowitsch ('12), and others.
GROWTH OF THE INNER EAR OF ALBINO RAT 39
By using this vital-fixation method we get perfect sections which
can be used to solve the problem of the shifting of the organ
of Corti an event which I will discuss later.
2. Membrana basilaris. The membrana basilaris of the
cochlea stretches between the limbus laminae spiralis and the
ligamentum spirale. The acoustic terminal apparatus is situated
on it and according to the dominant Helmholtz-Hensen theory,
this membrane is to be considered as very important in tone
perception. The row of the fine holes, foramina nervina,
is generally designated as the inner boundary of this membrane.
Strictly speaking, however, the beginning of the membrane is
at the outer edge of the labium tympanicum, which sharpens at
first beyond the foramina nervina and passes over to the substance of the membrana basilaris. Practically it is almost
impossible to decide exactly the point of transition. Thus I
have used in the measurement of the membrane the foramina
of the habenula perforata as an inner limiting line following in
this Retzius, ('84) Schwalbe ('87), and others. Here it is to be
mentioned that the organ of Corti lies with its inner portion
not only upon the inner part of the membrane, but extends to
the foramina nervina also.
The membrana basilaris is usually divided into two portions;
the inner, termed the zona arcuata, and the outer, the zona
pectinata. The former stretches from the habenula perforata
across the base of the tunnel of Corti to the outer edge of the
foot of the outer rods of Corti ; the latter extends from this point
to the ligamentum spirale (fig. 2), 5= inner zone, 10= outer zone.
In table 9 (chart 7) are given the values for the total radial
breadth of the membrane, that of each zone, and the ratios
between them. At the bottom of each column are given the
ratios at 1 to 546, 12 to 546, and 20 to 546 days of age. In the
total radial breadth of the membrane, as the table shows, there
are large differences on age from birth to nine days. Between
1 day and three days the increase is 30 |x and between three days
and six days, 28 [A. After nine days the breadth increases more
slowly but continuously to old age.
40
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
In the growth of both zones we see about the same relation.
These increase rapidly from birth till nine (or twelve) days and
after that very slowly. These relations are shown clearly in
the ratios at 1 to 546, 12 to 546, and 20 to 546 days. While after
twelve days the ratios in total breadth and in each zone are
the same, 1:1.1, that for 1 to 546 days is smaller for the outer
zone than it is for the inner zone, thus the inner zone increases
TABLE 9
Radial breadth of Ihe membrana basilaris measured between the foramina nervina
and ligamentum spirale in radial sections on age (chart 7, fig. 2}
AGE
BODY WEIGHT
INNER ZONE
(Zona
arcuata)
OUTER ZONE
(Zona
pectinata)
Total radial
breadth of
the membrane
Ratios between
the radial breadth
of the inner and
outer zone
days
grams
P
M
M
M
1
5
49
75
124
1 1.5
3
8
63
91
154
1.5
6
11
77
105
182
1.4
9 1
10
79
111
190
1.4
12
13
- 88
100
188
1.1
15
13
87
102
189
1.2
20
29
86
106
192
1.2
. 25
36
87
108
195
1.2
50
59
88
107
195
1.2
100
112
92
106
Id8
1.2
150
183
92
107
199
1.2
257
137
92
107
199
1.2
366
181
93
111
204
1.2
546
255
94
113
207
1.2
Ratios 1 546 days
1 1.9
1 1.5
1 1.7
12546 "
1.1
1.1
1.1
20546 "
1.1
1.1
1.1
1 A rat of nine days which could hear, gave the following:
Right side 11
94
103
197
91
104
195
93
104
196
1 : 1.1
considerably after birth, while the outer zone does not grow,
as some authors have imagined, as much as the inner zone.
I will discuss this point later.
Comparing the growths of the radial breadth of the inner
and outer zones, we find that the inner zone is relatively narrow
at nine days; thus the ratios between them are 1:1. 4; after that
period the inner zone increases rapidly, and even at twelve
days the ratio becomes 1:1.1, which is almost the same as in
the adult, 1:1.2.
GROWTH OF THE INNER EAR OF ALBINO RAT
41
In table 10 the radial breadths of the whole membrane and
of its zones are arranged accordingly to the turns of the cochlea
on age. At the bottom of each column are given the ratios
from 1 to 546, 12 to 546, and 20 to 546 days. We see at first
that the total radial breadth at one day is largest in the basal
turn; at three days it becomes larger on passing from the basal
toward the II and III turns, but in turn IV it is again small.
220
M
180
140
100
60
20
i
*
^
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-
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r
r
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E
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25 50 50 , oo 20O 3OO 4OO 5OO
Chart 7 The radial breadth of the membrana basilaris, table 9, figure 2,
distance 11.
Total radial breadth of the membrane.
Radial breadth of the zona pectinata.
Radial breadth of the zona arcuata.
After six days it is a well-known fact that the radial breadth of
the membrana basilaris is narrowest in the basal, and widest
in the apical turn (not the tip of the apex, but the beginning
of the apical turn). These differences are not always the same
between all the turns; those between I and II, and II and III
are marked; those between III and IV are small. The ratios
at 1 to 546 days show those for the upper turn to be largest,
while from 12 to 546, and 20 to 546 days the ratios in all turns
are about 1:1.1.
42
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
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1
p
4
L i-l CO D 3> 04 *Q 'O lO'Q O Q b D <D
t-li-H<NiMiOOiOiOO'* 1
-i T-I (N CO U5
03
tn ^3
Is
?
rH
CO
-f
o
n
i-H
20-546 "
1 A nil
Right side
Left side
Average
GROWTH OF THE INNER EAR OF ALBINO RAT
43
In the zona arcuata (inner zone) the same relation is to be
seen in each turn; therefore, in the early period the breadth
is less in turn IV than in the other turns. Very soon, however,
the value in turn IV becomes the largest and diminishes toward
the base. The rate of the growth of this zone, from 1 to 546 days,
is also smallest in turn I, and largest in turns III or IV; the
ratios being in the first 1:1.6, and in the last 1:2.1.
In the zona pectinata (outer zone) we see also similar relations.
TABLE 11
Ratios of the radial breadth of the membrana basilaris according to the turns of the
cochlea on age
AGE
BOOT WEIGHT
Ratios between turns
I-II
I-III
I-IV
days
gms.
1
5
1
1.0
1
1.0
1
1.0
3
8
1.0
1.0
1.0
6
11
1.1
1.2
1.2
9
10
1.1
1.2
1.1
12
13
1.2
1.3
1.3
15
13
1.1
1.3
1.3
20
29
1.1
1.2
1.3
25
36
1.2
1.3
1.3
50
59
1.1
1.3
1.3
100
112
1.1
1.3
1.3
150
183
1.1
1.2
1.3
257
137
1.1
1.2
1.3
366
181
1.1
1.2
1.3
546
255
1.1
1.2
1.3
Only slight differences in the ratios according to age are found.
In table 11 the ratios according to the turns of the cochlea
are given. While from one to three days the ratios are the same
in each turn, 1:1.0, yet after six days those for turns I to II are
smallest, and for I to IV larger, thus showing slight differences
between them.
In the literature we find only one description, that by Retzius
('84) touching the growth of the radial breadth of the membrana
basilaris according to age. He measured this membrane in the
rabbit and cat and got the following values in n (table 12).
44
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
Comparing these values with mine obtained for the albino
rat, it is to be noted that those of Retzius are generally larger
than those for the albino. For example, while I get at birth
only 126 (x in the basal turn, Retzius ('84) obtains 180 [x in the
rabbit and even 270 [x in the cat. As stated above, the radial
breadth increases in the albino rat continuously with age. It
is very peculiar to find in the Retzius table that the breadth
of the membrane in the cat is decidedly larger at birth than at
three and seven days. The average value for the new-born is
315 [x, which is larger than at thirty days, which is 310 [x.
Retzius ' data show the membrane in the rabbit and cat always
wider in the apical than in the basal turn at birth and at two
TABLE 12
Breadth of membrana basilaris according to turns, p. (From Retzius, '84}
RABBIT
CAT
Age
Basal
Middle
Apical
Basal
Middle
Apical
days
New-born
180
270
270
300
375
2
220
272
280
3
.
200
280
7
270
306
211
258
300
10
255
310
390
11
255
300
330
14
300
360
410
30
240
300
390
days. My results, given in table 10, show the reverse at the
ages of one and three days. This is an expression of greater
immaturity in the case of the rat.
In comparisons like the foregoing, several conditions must
be kept constantly in view.
So far as absolute values are concerned, it is to be expected
that these would be unlike in the different mammals, because
the cochleas differ in size. As to the relations between the values
at birth and at maturity, it is plain that these cannot be expected to agree unless the cochleas of the animals compared
are in the same phase of development at birth. In the foregoing
instances it appears that the cat is relatively precocious, as
compared with the rabbit, while, as might be expected, because
GROWTH OF THE INNER EAR OF ALBINO RAT
45
of their closer zoological relationship, the rat and the rabbit are
in better agreement, although the rabbit appears to be a trifle
more advanced at birth than the rat.
Finally, in the comparison of different series of data, differences due to the lack of homogeneity in the series of animals
used and to the various techniques employed can hardly fail to
play an important part, and allowance must be made for these
disturbing factors.
When we consider the rate of growth, the ratio of a one to a
fourteen-day-old rabbit is 1:1.6, according to Retzius; therefore,
TABLE 13
Breadth of basilar membrane
ANIMAL
AUTHOR
TURN IN WHICH MEASUREMENT WAS MADE IN M
Basal
Second
Third
Fourth
Average
Man-New-born
Hensen ('63)
235
413
495
381
Man Mature
Retzius ('84)
210
340
360
303
Calf
Kolmer ('07)
200
280
400
293
Pig
Kolmer ('07)
168
200
256
304
232
Goat
Kolmer ('07)
124
384
432
313
Cat
Bottcher ('69)
90
435
263
Cat
Middendorp ('67)
246-275
it has very nearly the value found in the albino. In the cat,
however, the ratio between one and thirty days is 1:0.97; therefore, it apparently decreases a bit.
This difference is most readily explained as due to the
precocious development in the cat at birth.
On comparing the radial breadth of the membrane obtained
from several mammals by various authors, we find the following
values (table 13).
The values here given must be read in the light of the various
modifying conditions to which reference has just been made.
46 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
My average value after twenty days is 199 [i; therefore, it
is absolutely the smallest in this series of mammals. The rat
is also the smallest species examined.
As shown in the literature quoted, and also in my own results,
the membrane increases in its breadth in all the mammals examined from the base toward the apex a relation contrary to
that reported by the older authors (Corti, '51, and others).
This increase is continuous, but is at first more rapid and afterwards more gradual. The ratios of this increase in the albino
rat are given in table 11.
The next question relates to the breadth of each zone of the
membrane according to age. So far as I know, there is no such
study in the literature, not even in Retzius. In the albino rat,
as shown in table 9, each zone increases in breadth with age.
The rate of growth, however, is somewhat different, and in the
zona arcuata it is greater than in the zona pectinata (1:1.9 and
1 :1.5, respectively), although the absolute value is always greater
in the latter.
As noted above, the membrane increases in its radial breadth
from the basal to the apical turn. How, and in which portion
of the membrane does this increase arise? Henle ('66) first
regarded the breadth of the inner (zona arcuata) as approximately constant.
"Nicht nur in den verschiedenen Regionen einer Schnecke,
sondern, soviel ich sehe, selbst in den Sshnecken verscheidener
Tiere und des Menschen; sie schwankt nur wenig um 0.01 mm."
(Eingeweidelehre des Menschen, 1866, S. 793).
In the second edition of his book ('73) he states, however,
that in the increase of the breadth according to the turn, both
zones seem to take part. Hensen ('63) gets in the zona arcuata
of the base of the human cochlea the breadth of 19 ^ and in the
apex 85 \L. Middendorp ( '68) gives in the cochlea of the cat a
continuous increase of the breadth of the zona arcuata from 94
to 122.5 {A. ."''"'
More detailed data are given in table 14.
According to all these authors, the breadth of both the inner
and outer zones increases from base toward apex and results
GROWTH OF THE INNER EAR OF ALBINO RAT
47
in the increase of the total radial breadth of the membrane
according to turn. My results obtained from the albino rat
agree with these data.
3. Radial distance between the habenula perforata and the
inner corner of the inner pillar cells at base. The measurements
of the radial distance from the habenula perforata to the bases of
the inner and outer pillar cells were taken to determine their
postnatal growth. As already stated, the cells from which the
arch of Corti arises stand at birth nearly vertically and have no
space between them (fig. 4). In the adult, however (fig. 10),
we see a space, the tunnel of Corti lying between them and
changes in the form of the arch occur. To follow these changes
TABLE 14
Breadth of the inner zone of the membrana baeilaria in n
NUMBER Of TURN
First
Second
Third
Fourth
Cat-adult
Bottcher ('69)
60
105
135
Guinea-pig
Winiwarter (70)
45-52
63-68
71-80
80-83
it seems at first necessary to study the growth of the pillar
cells and of the other elements in the organ of Corti. At the
same time we must take into consideration the inward shifting of
the organ of Corti, first studied by Hensen. This shift inward
of the organ is, according to Hensen, chiefly caused by the
wandering of the pillar cells, especially the inner pillar cell.
Therefore, it seemed necessary to determine the radial distance
of the pillar cells from the habenula perforata at different ages
before discussing this interesting problem.
In table 15 are given the values for the radial distances between
the habenula perforata and the inner corner of the inner pillar
cell at its base according to age (figs. 4 to 9). As we see, the
average value increases till three days of age, then vanishes
suddenly, though at six days we have a measurable interval
in the upper turns of the cochlea. Comparing these distances
according to the turn, they are smallest in turn I and increase
48
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
toward the apex. In some cases, at six days, we have no interval
in the basal turn, but in the higher turns an interval gradually
appears and at the apical turn is largest. This table shows,
therefore, that the inner corner of the base of the inner pillar
cell lies at birth outward from the habenula perforata at an
TABLE 15 Condensed
Radial distance between the habenula perforata and the inner corner of the inner
pillar at base on age
AGE
BODY
WEIGHT
TURNS OF THE COCHLEA M
I
II
ill
IV
Aver.
days
1
5
19
22
22
23
22
3
8
23
28
28
30
27
6
11
In one case 5
In 2 cases 10
14
18
In other 3 cases
In other cases
9
10
12
13
average distance of 22 \L. At three days of age the inner corner
moves farther outward with the developing membrana basilaris
and the distance increases from the base to the apex. Between
three to six days this outward movement not only stops, but
reverses its direction, and at six days it often becomes zero in
the basal turn. Bottcher ('72) finds in the cat the following
values for this interval in \i (table 16).
TABLE 16
CAT EMBRYO 11 CM. LONG
ADULT CAT
I
II
ill
IV
Average
I
II
ill
IV
Average
15
39
30
30
29
3
3
3
3
3
TABLE 17
BABBIT
CAT
AGE
Basal
turn
Middle
Apical
Average
Basal
Middle
Apical
Average
days
New-born
300
300
300
300
5
40
45
30
2
10
12
30
17
3
3
36
7
11
18
GROWTH OF THE INNER EAR OF ALBINO RAT 49
Retzius ('84) studied this distance in the rabbit and cat and
gets the values given in Table 17.
Comparing the values of these two authors with my own,
there are of course some differences. While in the rabbit the
interval is large at one day, it is greatly diminished at two days
of age. At three days the inner corner of the cell reaches the
habenula perforata. In the cat the values are nearer to mine.
The fact that the values increase from base toward apex is to
be seen here also. This peculiar phenomenon appears, therefore
not only in the albino rat, but also in the rabbit and the cat
during the earliest stage of postnatal life.
4- The radial distance between the habenula perforata and the
outer corner of the inner pillar cell (resp. the inner corner of the
outer pillar cell) at base. This measurement is difficult. As we
know, the inner and outer pillar cells in the albino are from birth
till nine days of age in contact with each other along their whole
length, and therefore they do not yet surround the space forming
the tunnel of Corti. At about nine days, however, the tunnel
appears while the cells remain in contact by their bases. It
is almost impossible to determine the line of contact on the
basilar membrane in my preparations. To get the radial distance
between the habenula perforata and the outer corner of the inner
pillar cell I have proceeded therefore as follows:
First, I have measured this distance directly up to nine days
of age; after that this distance consists of the sum of the radial
basal breadth of the inner pillar (not pillar cell) and the breadth
of the inner basal cell on the basilar membrane. Since it is
impossible to get the latter value directly in my sections, I
considered that half of the radial distance between the outer
corner of the inner pillar and the inner corner of the outer pillar
would be equivalent to it.
Of course, I do not know whether the value of the sum of
these two distances is at all ages, identical with the distance
between the habenula perforata and the outer corner of the inner
pillar cell at its base. I believe, however, that a systematic
study of the growth of this distance will be significant.
50
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
In table 18 are given the values for the radial distance between
the habenula perforata and the outer corner of the inner pillar
at base up to nine days of age. As shown, these values, on the
average, increase with age. The increase of this distance means
that the base of the inner pillar cell spreads outward more and
more.
When we consider this distance according to the coil of the
cochlea, it is at birth about the same through all the turns
(table 18; at three days it increases up to turn III, and in turn
TABLE 18
Radial distance between the habenula perforata and the outer corner of the inner
pillar at base on age
TURNS OF COCHLEA M
AGE
BODY WEIGHT
I
II
III
VI
Average
days
grams
1
5
40
41
39
39
40
3
8
48
49
50
48
48
6
11
38
45
58
53
49
9
10
44
46
56
53
50
IV the value is the same at the apex as at the base. At six days
the value in turn III is also largest, and next largest in turn IV.
At nine days of age the same relations are to be seen.
In table 19 (chart 8) are given the values for the radial basal
breadth of the inner pillar (not pillar cell) on age. At the bottom
of the last column are the ratios from 6 to 546, and 20 to 546
days. As above noted, the rod can be followed at birth from
the upper part to near the base of the cell (fig. 4). At three days
(fig. 5), its base reaches the basilar membrane as a thin and slender
thread, but we cannot measure its basal breadth accurately.
During the next few days it increases in radial breadth rapidly,
and at six days has the average value of 29 [/. (table 19). After
nine days it decreases distinctly till twenty days, after which
the value remains nearly constant. These relations are evident
in the ratios. While the breadth at six days is about twice
that at 546 days, that at twenty days has the same value.
GROWTH OF THE INNER EAR OF ALBINO RAT
51
According to the turn of the cochlea, the values from nine
to fifteen days become gradually larger on passing from the
base toward the apex. After twenty days, however, this relation
vanishes, and the values become nearly the same through all
TABLE 19
Radial basal breadth of the inner pillar on age (chart 8)
day*
1
3
ti
9
12
15
20
25
50
100
150
257
366
546
Ratios 6
20
WEIOHT
BODY
TURNS OF THE COCHLEA M
I
II
III
IV
Average
grams
5
8
11
29
31
27
27
29
10
28
28
33
35
31
13
18
19
22
25
21
13
18
18
19
19
19
29
14
15
15
15
15
36
14
15
14
15
15
59
14
14
14
13
14
112
14
14
14
13
14
183
15
15
15
15
15
137
15
15
15
15
15
181
16
17
15
15
16
255
15
14
16
15
15
-546 days
1 :0.5
-546 "
: l.o
40
U
20
n
"
\
Ab
DA'
/q
a
25 5O 5Q IOO 20O 3OO 4OO 5OO
ChartS. The radial basal breadth of the inner pillar (not pillar cell),
table 19, figure '2, distance 3.
the turns. In table 20 the ratios of the turns I to II, I to III,
and I to IV are given for three age groups (condensed from table
52
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
From the data given by Retzius ('84) we get the values in jx
of the radial basal breadth of the inner pillar in the rabbit and
cat as follows (table 21).
Comparing these values with my own, it is to be noted that
Retzius' measurements in the rabbit agree perfectly at the
earliest stage with those in the albino rat. Also we find in the
TABLE 20 Condensed
Ratios of the radial basal breadth of the inner pillar according to the turns of the
cochlea on age
RATIOS
BETWEEN TTTBN8
AGE
BODY WEIGHT
I-II
I-III
I-IV
days
grams
8
11
1 1.0
1 1.0
1 1.1
14
13
1.1
1.2
1.3
189
124
1.0
1.0
1.0
TABLE 21
Radial basal breadth of inner pillar in n (Retzius)
BABBIT
CAT
Age
Basal
turn
Middle
Apical
Average
Basal
Middle
Apical
Average
days
New-born
11
2
3
12
7
15
12
15
14
10
15
10
17
18
18
18
11
15
15
14
15
15
12
14
30
9
12
15
12
rabbit at seven days values homologous with those obtained in
the albino rat at fifteen days of age, only in the rat the breadth
is absolutely greater. In the cat the values at seven days of
age are about the same, or a bit smaller, than those in the albino
rat. Here again the rabbit is a trifle more precocious than the
rat, and the cat much more so.
Table 22 (chart 9) shows the values for the radial distance
between the outer corner of the inner pillar (not pillar cell)
GROWTH OF THE INNER EAR OF ALBINO RAT
53
TABLE 22
Radial distance between the outer corner of the inner pillar and the inner corner of
the outer pillar at base on age (chart 9)
AGE
BODY WEIGHT
TURNS OF THE COCHLEA M
I
II
III
IV
Average
days
grams
1
5
3
8
6
11
25
28
29
34
29
9
10
27
30
35
30
31
12
13
37
41
51
53
46
15
13
35
46
56
56
48
20
29
43
53
66
68
58
25
36
42
58
67
68
59
50
59
41
54
68
74
59
100
112
44
59
71
78
63
150
183
43
59
68
76
62
257
137
46
56
66
75
61
366
181
45
57
68
74
61
546
255
47
60
71
74
63
Ratios 6546 days
12546 "
20546 "
2.2
1.4
1.1
ou
14,
60
40
20
r\
<
t=
MM
.
=
1
/
i
/
i
1
G
E
DA>
/C
1
13
o
25
50
50 1OO 20O 3OO 40O 5OO
Chart 9. The radial distance between the outer corner of the inner pillar
(not pillar cell) and the inner corner of the outer pillar (not pillar cell) at base,
table 22, figure 2, distance 6.
54
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
and the inner corner of the pillar (not pillar cell) at the base,
on age. At the bottom of the last column are given the ratios
from 6 to 546, 12 to 546, and 20 to 546 days. As just stated,
the inner, and especially the outer rods, do not appear in the
respective pillar cells at the earliest stage, the latter becoming
evident a bit later than the former. After six days of age the
distance between them can be determined.
As table 22 shows, this distance increases at first rapidly,
then more slowly with age. This agrees with the growth of the
membrana basilaris, as already noted. While the value at 546
days is over twice as large as at six days, it is but little larger
than at twenty days, as the ratios show. Moreover, the distance
increases from the base toward the apex rapidly up to turn
TABLE 23 Condensed
Ratios of the radial distance between the outer corner of the inner pillar and the
inner corner of the outer pillar, at base according to turns
of the cochlea on age
BATIO8 BETWEEN TURNS
I-II
i-m
I-IV
days
grams
8
11
1 : 1.1
1 : 1.2
1 : 1.2
14
13
: 1.2
: 1.5
: 1.5
189
124
:1.3
:1.5
:1.7
III and less rapidly to turn IV. This relation is more concisely
presented in table 23. Retzius ('84) gives the value of this
distance in the rabbit and the cat as follows (table 24).
The table 24 shows that there is no measurable distance
between the outer corner of the inner pillar and the inner corner
of the outer pillar at the very early stage in the rabbit, and this
result is like that for the albino rat. Later the distance is larger
in the rabbit than in the rat. The rate of increase of the values
from the base to the apex is, however, similar in both forms.
In the cat, on the other hand, there is already at birth a large
distance between the pillars. The cochlea of the cat is therefore at this period more advanced in this character than that of
the rabbit or rat, but in the cat also the distance tends to increase from the base toward the apex.
GROWTH OF THE INNER EAR OF ALBINO RAT
55
In table 25 (chart 10) are given the values for the radial
distance between the habenula perforata and the outer corner
of the inner pillar cell (resp. the inner corner of the outer pillar
cell) at the base according to age. This table is derived from
tables 18, 19, and 22. The values from one to nine days of age
are from table 18. Those after twelve days consist of the sum
of the values in table 19 plus the one-half of those given in table
22 (fig. 2 value for bracket 3 plus one-half the value for bracket
6).
TABLE 24
Radial distance between the outer corner of the inner pillar and inner corner of the
outer pillar in n (Retzius)
RABBIT
CAT
Age
Basal
turn
Middle
turn
Apical
turn
Average
turn
Basal
turn
Middle
turn
Apical
turn
Average
turn
days
New-born
64
2
3
45
7
57
75
75
69
50
75
10
52
72
74
66
11
75
95
14
63
100
99
87
30
66
93
90
83
The values increase gradually after birth till nine days, when
they reach a maximum, and then decrease, but increase again
very gradually till old age. If this method of measurement is
accepted, then the inner corner of the inner pillar cell lengthens
inward at the base in the earlier stages. At the time when the
inner pillar reaches the habenula perforata, the outer corner
of the inner pillar has not yet moved inward, and thus the breadth
of the base is largest. After the inward wandering of the inner
pillar cell, the base diminishes a little in its breadth; then it
increases slightly with advancing age.
When considered according to the turn of the cochlea, this
measurement generally increases from the base to the apex,
but more rapidly from turn I to turn III, and only slightly from
56
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
TABLE 25
Radial distance between the habenula perforata and the outer corner of the inner
pillar cell (resp. the inner corner of the outer pillar cell) at base on
age. Derived from tables 18, 19 and 22 (chart 10)
AGE
BODY WEIGHT
TURNS OF THE COCHLEA M
I
II
III
IV
Average
days
grams
1
5
40
41
39
39
40
3
8
46
49
49
49
48
6
11
38
45
58
53
49
9
10
44
46
56
53
50
12
13
36
45
50
50
45
15
13
36
41
47
47
43
20
29
36
42
48
49
44
25 .
36
35
44
48
49
44
50
59
35
41
48
50
44
100
112
36
44
50
52
46
150
183
36
45
49
53
46
257
137
38
43
48
51
45
366
181
39
45
49
52
46
546
255
39
44
52
52
47
Ratios 1 546 days
9546 "
12546 "
20546 "
1.2
0.9
1.0
1.1
60
JLL
40
20
c\
^
r*
r^
_ !
1
e=
-_
G
^
c
A
/s
25
50
50 1OO 2OO 3OO 4OO 5OO
Chart 10 The radial distance between the habenula perforata and the
outer corner of the inner pillar cell (resp. the inner corner of the outer pillar
cell) at base, table 25, figure 2, distance 8.
GROWTH OF THE INNER EAR OF ALBINO RAT
57
turn III to IV. Table 26 shows this relation. While at birth
the ratio is in all turns the same, 1 :1.0, at other ages it is always
higher. Retzius ( '84) gives the results obtained from the rabbit
and the cat as follows (table 27).
TABLE 26 Condensed
Ratios of the radial basal distance between the habenula perfcrata and the outer
corner of the inner pillar cell (resp. the inner corner of the outer pillar
cell) at base on age according to the turns of the cochlea
RATIOS BETWEEN TURNS
AGE
BODY WEIGHT
I-I1
I-HI
I-IV
days
gram*
1
5
1 1.0
1 :1.0
1 :1.0
8
11
1.2
:1.4
: 1.3
18
21
1.2
:1.3
: 1.3
213
138
1.2
:1.S
:1.4
TABLE 27
Distance between the habenula perforata and the outer corner of the inner pillar
cell in n (Retzius)
Age
Basal
turn
Middle
turn
Apical
turn
Average
turn
Basal
turn
Middle
turn
Apical
turn
Average
turn
days
New-born
30
45
39
38
60
60
60
60
2
30
36
30
32
3
44
60
7
37
46
45
43
45
69(?)
65
60
10
39
52
48
46
11
60
66
75
67
14
40
54
51
48
30
60
60
At the earlier stage this distance in the rabbit is a little less
than in the rat. Soon after, however, it becomes about the same.
In the cat the values are generally larger than in the rat.
5. Radial basal breadth of the outer pittar cett (including
the outer pillar). The measurement of the radial basal breadth
of the outer pillar cell is difficult. At the earlier stage, in which the
inner and outer pillar cells are in contact with each other along
58
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
Radial basal breadth of the outer pillar cell (including the outer pillar) from one
to nine days of age
TURNS OF THE COCHLEA M
AGE
BODY WEIGHT
I
II
III
IV
Average
days
grams
1
5
10
9
8
8
9
3
8
15
16
15
12
15
6
11
26
28
28
33
28
9
10
26
30
30
35
30
TABLE 29
Radial basal breadth of the outer pillar on age (chart 11)
AGE
BOOT WEIGHT
TURNS OF THE COCHLEA M
I
II
III
IV
Average
days
grams
1
5
3
S
6
11
10
14
16
17
14
9
10
15
18
18
21
18
12 .
13
14
23
25
22
21
15
13
17
21
23
20
20
20
29
13
13
16
15
14
25
36
14
13
14
14
14
50
59
14
14
15
14
14
100
112
14
15
16
15
15
150
183
15
15
15
16
15
257
137
15
16
17
17
16
366
181
15
16
17
18
16
546
255
16
15
17
17
16
Ratios
1
2
40
A
20
n
6546 days 1
2546 "
0546 "
1.1
0.8
1.1
t
\,
1
-=a
<
-<
,
G
D
A'
^
i
25
50
5O 1OO 2OO 300 4OO 500
Chart 11 The radial basal breadth of the outer pillar (not pillar cell)
table 29, figure 2, distance 7.
GROWTH OF THE INNER EAR OF ALBINO RAT
59
their whole length, we can easily measure this distance. After
twelve days, however, the breadth consists of the sum of the
radial breadth of the outer pillar and the half of the radial
distance between the outer corner of the inner pillar and the
inner corner of the outer pillar, as previously explained.
In table 28 are given the values for the radial basal breadth
of the outer pillar cell (including the outer pillar) from birth
to nine days of age. These values show a rapid increase. According to the turn of the cochlea, the breadth at birth diminishes
from the base to the apex. At three days it increases already in
turn II, but at the later ages it increases gradually from the
base to the apex.
TABLE 30 Condensed
Ratios of the radial basal breadth of the outer pillars on age according to the
turns of the cochlea
RATIOS BETWEEN TURNS
AGE
BODY WEIGHT
I-II
I-III
I-IV
days
grams
8
11
1 -1.2
1 1.3
1 1.5
14
13
:1.4
1.5
1.3
189
124
: 1.0
1.1
1.1
In table 29 (chart 11) are given the values for the radial
basal breadth of the outer pillar (not pillar cell). As in the case
of the inner pillar, here also the outer pillar first appears distinctly
at six days of age. After the continuous increase of the values till
twelve to fifteen days, they decrease suddenly at twenty days,
and then increase again very slowly. This relation is clearly
shown by the ratios at the bottom of the last column. That
the values tend to increase from the base toward the apex is
also shown, though there are some exceptions. Table 30 gives
the condensed results.
From Retzius' work ('84) we have calculated the values for
the radial basal breadth of the outer pillar in the rabbit and cat
as follows (table 31).
There are large differences between my results and those
of Retzius during the earlier stage, especially in the rabbit.
60
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
At birth, the inner pillar has not yet distinctly developed at
the base of the pillar cell in the rabbit and the rat, as above
stated. We know that the development of the elements of
the cochlea proceeds generally from the axis to the periphery, as
TABLE 31
Radial basal breadth of outer pillar measured in n (from Retzius)
RABBIT
CAT
Age
Basal
turn
Middle
turn
Apical
turn
Average
Basal
turn
Middle
turn
Apical
turn
Average
days
,
New-born
15?
12?
7?
11?
25
15
2
50
45
44
46
3
20
7
28
28
17
24
18
20
18
19
10
31
30
37
33
11
30
19
14
28
25
18
24
30
10
15
15
13
TABLE 32
Radial basal breadth of the outer pillar cells on age, based on tables 22, 28, and
29 (charts 12 and 18)
AGE
BODY WEIGHT
TURNS OP THE COCHLEA M
I
II
III
IV
Average
days
grams
1
5
10
9
8
8
9
3
8
15
16
15
12
15
6
11
26
28
28
33
28
9
10
26
30
30
35
30
12
13
33
38
48
52
43
15
13
35
44
50
48
44
20
29
35
40
49
49
43
25
36
35
42
48
48
43
50
59
35
41
49
51
44
100
112
36
45
52
54
47
150
183
36
45
49
54
46
257
137
38
44
50
53
46
366
181
38
43
51
55
47
546
255
40
45
53
54
48
Ratios 1 546 days
9546 "
12546 "
20546 "
1 :5.4
: 1.6
: 1.1
: 1.1
GROWTH OF THE INNER EAR OF ALBINO RAT
61
Held ('09) and others have pointed out. Yet, according to
Retzius, the outer pillar develops in the rabbit earlier than does
the inner pillar. This result seems to me very peculiar, but,
at present, I am unable to explain it.
In table 32 (charts 12 and 13) are given the values for the
radial basal breadth of the outer pillar cells. These data are
ou
M.
40
20
.-'
>-i
^
a*
-^
'
1
/
r~
G
:
DA >
/c
25 50 50 1OO 20O 30Q 4(X) 5QO
Chart 12 The radial basal breadth of the outer pillar cell, table 32, figure 2,
distance 9.
5O 50 1OO 2OO 30O 40O 50O
Chart 13 The radial basal breadth of the outer pillar cell, according to
the turns of the cochlea, table 32, figure 2, distance 9.
derived from tables 22, 28, and 29. At the foot of the last column
are given the ratios from 1 to 546, 9 to 546, 12 to 546, and 20
to 546 days. The values increase rapidly during the earlier
stage, but after twelve days very slowly, as the ratios show.
The breadth is, at birth, largest in the basal and smallest
in the apical turn. Very soon, however (six days), the reverse
62
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
relation appears, and the breadth increases from the base
to turn III relatively rapidly, but from turn III to IV slowly.
In table 33 the ratios are given in a condensed form. The radial
breadth of the outer pillar cells as given by Retzius ('84) are
as follows (table 34.)
TABLE 33 Condensed
Ratios of the radial basal breadth of the outer pillar cells on age according to
turns of cochlea
RATIOS BETWEEN TtTRNS
AGB
BODY WEIGHT
I-II
i-in
I-IV
days
grams
1
5
1 :0.9
1 0.8
1 :0.8
8
11
1 1.1
1.2
:1.3
18
21
:1.2
1.4
: 1.4
213
138
:1.2
1.4
: 1.4
TABLE 34
Radial basal breadth of the outer pillar cells in n (Retzius)
RABBIT
CAT
AOE
Basal
turn
Middle
turn
Apical
turn
Average
turn
Basal
turn
Middle
turn
Apical
turn
Average
turn
days
New-born
21
22
23
22
36
30
30
32
3
30
40
30
33
3
36
30
7
65
66
60
64
36
54
36
42
10
52
60
69
60
'
11
50
60
18
43
14
57
80
80
72
30
60
60
This table shows that the breadth of the outer pillar cell increases in the rabbit and the cat continuously from birth to
old age, as I have found in the rat. Also the value is generally
smallest in the base, largest in the apex, though there are some
exceptions. The main differences between the results of Retzius
and mine is that the values in the rabbit are larger than in the
rat. This is probably due to the differences in the size of the
animals.
GROWTH OF THE INNER EAR OF ALBINO RAT 63
6. The radial distance between the habenula perforata and
the outer border of the foot of the outer pillar cell. The determination of this distance is deemed necessary not only as a datum
on growth in general, but also for its bearing on the difficult
question of the shifting of the outer pillar cell, to be discussed
later. On the other hand, this distance is identical with the
radial length of the zona arcuata of the membrana basilaris
(table 7. inner zone).
In table 35 (chart 14) are given the values for the radial
distance between the habenula perforata and the outer corner
of the outer pillar cell at base. At the foot of each column are
given the ratios at 1 to 12, 1 to 20, 1 to 546, and 20 to 546 days.
As table 35 shows, the distance increases continuously from birth
to old age, rapidly up to twelve days, but later gradually. Up
to three days the distance is slightly larger in the lower turns, but
after this age the relation is reversed, and this persists through life.
The increasing ratio of the distance for each turn according
to age is smallest in turn I and largest in turn IV. The ratios
for the condensed data are given in table 36. While the ratio
at birth is the same in each turn, 1:1.0, that of turn I to II is
smallest for every condensed age. Also it is to be seen that the
increase of the ratio in turn I to II is smallest and that in turns
I to IV is largest. In Retzius' work ('84) we find the following
values for this distance (table 37).
Table 37 shows that in the rabbit the growth changes are
similar to those in the rat, though the absolute values are somewhat
larger. As hi preceding determinations, the values for the cat
do not stand in the same relation as those for the rabbit, but
indicate precocity. Some corresponding observations by Hensen,
Bottcher, and others will be presented later.
7. The greatest height of the greater epithelial ridge (der grosse
Epithelwulst (Bottcher) s. Organon Kollikeri) resp. of the inner
supporting cells (fig. 4, G). The so-called greater epithelial ridge
is a prominence formed by high cylindrical pseudostratified cells.
It is situated axialward on the tympanic wall and continued
outward to the lesser epithelial ridge. About the fate of this
ridge there were various divergent opinions among the older
64
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
authors. Now, the view of Bottcher ( '69) is generally accepted.
This large prominence vanishes during development, and instead
of it a deep and wide furrow lined with low epithelium appears.
These epithelial cells become peripherally higher and finally lean
TABLE 35
Radial distance between habenula perforata and the outer corner of the outer pillar
cells at base on age (chart 14)- For the average values
see the third column in table 9
AGE
BODY WEIGHT
TURNS OF TBE COCHLEA M
I
II
III
IV
Average
days
yrams
1
5
50
50
48
48
49
3
8
63
65
64
58
63
6
11
64
73
86
86
77
9
10
70
76
86
86
80
12
13
69
83
98
100
88
15
13
70
84
98
95
87
20
29
71
81
96
98
87
25
36
71
86
95
97
87
50
59
69
83
96
102
88
100
112
73
88
101
106
92
150
183
73
89
98
107
92
257
137
76
87
98
107
92
366
181
76
89
100
107
93
546
255
78
89
104
106
94
Ratios 1 12 days
1 20 "
1546 "
20546 "
1.4
1.4
1.6
1.1
: 1.7
: 1.6
:1.8
: 1.1
1 -2.0
:2.0
:2.2
1 :2.1
:2.0
:2.2
: 1.1
: 1.8
: 1.8
: 1.9
: 1.1
100
80
60
40
AG^E DAYSH
O
25 5O 50 too 2OO 3OO 40O 500
Chart 14 The radial distance between the habenula perforata and the
outer corner of the outer pillar cell at base, table 35, figure 2, distance 5.
GROWTH OF THE INNER EAR OF ALBINO RAT
65
on the inner supporting cells, which are termed ' Grenzzellen '
by Held ('02). The latter belong, of course, to this ridge, since
the inner hair cell marks the outmost row in the ridge. The
'Grenzzellen' of Held, however, are different from other high
cylindrical cells in the ridge, as they have a very intimate relation
with the ' Phalangenzellen ' of Held, stand with their bases just
TABLE 36 Condensed
Ratios of the radial distance between the habentda perforata and the outer corner
of the outer pillar cells at base on age
RATIOS BETWEEN TURNS
AVERAGE AGE
AVERAGE BODY
WEIGHT
I-II
i-in
I-IV
days
grams
1
5
1 :1.0
1 :1.0
1 :1.0
8
11
: 1.1
:1.3
: 1.2
18
21
:1.2
: 1.4
: 1.4
213
138
: 1.2
: 1.3
: 1.4
TABLE 37
Radial distance between habenula perforata and the outer corner of the outer pillar
cells at base in n (Retzius)
RABBIT
CAT
Age
Basal
Middle
Apical
Average
Basal
Middle
Apical
Average
turn
turn
turn
turn
turn
turn
turn
turn
days
New-born
75
80
75
77
105
105
120
110
2
80
90
100
90
3
80
120
7
100
115
107
107
78
110
120
103
10
100
120
129
116
11
120
129
108
119
14
106
140
129
125
30
85
120
120
108
outward from the habenula perforata and serve to support the
inner hair cell as Deiters' cells support the outer hair cells.
Thus the greater ridge includes in its prominence three kinds
of cells, the high cylindrical cells, the 'Grenzzellen' of Held and
the inner hair cell.
The greatest height of this ridge is not situated at a fixed
point, but first lies somewhat outward from the middle part and
66
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
after the furrow appears, passes outward towards the inner
supporting cells. Thus the greater ridge decreases in thickness
from birth to nine days of age, then increases gradually to twenty
days. After twenty-five days the values diminish again very
slowly but continuously.
In table 38 (charts 15 and 16) are given the values of the greatest
height of the greater epithelial ridge from the basilar membrane
TABLE 38
Greatest height of the greater epithelial ridge (resp. of the inner supporting cells)
on age (charts 15 and 16)
Bodv wcifitlitj
TURNS OF COCHLEA M
I
II
III
IV
Average
height
days
1
grams
5
68
65
66
63
66
3
8
49
49
56
57
53
6
11
40
40
41
40
40
9
10
36
40
41
42
40
12
13
38
41
48
53
45
15
13
44
46
52
58
50
20
29
50
53
63
66
58
25
36
51
51
63
63
57
50
59
50
50
59
63
56
100
112
48
49
59
63
55
150
183
47
49
56
61
53
257
137
47
51
56
62
54
366
181
46
49
57
60
54
546
255
44
50
56
60
53
Ratios 1 9 days 1:0.6
12 20 " :1.3
12546 " :1.2
20546 " :0.9
1546 " :0.8
through the summit of the supporting cells, according to age.
At the bottom of the last column is given the ratio at 1 to 9,
1 to 546, 12 to 20, 12 to 546, and 20 to 546 days of age.
The values in turn I are at birth the largest, but at three
days the relation is reversed and remains so in the later age
groups. Table 39 shows this relation from the condensed data.
Retzius ('84) gives in the rabbit and cat the following values
(table 40).
GROWTH OF THE INNER EAR OF ALBINO RAT
67
In the rabbit the values decrease from birth till ten days,
then increase; therefore, they agree in general with my results
50
40
30
;
25
50 50 10O 20O 30O 40O 500
Chart 15 The greatest height of the greater epithelial ridge (resp. of the
inner supporting cells) table 38, figures 4 to 12.
70
44
60
5O
40
30
s
o
25
50
50 IOO 20O 3OO 4OO 500
Chart 16 The greatest height of the greater epithelial ridge (resp. of the
inner supporting cells) arranged according to the turns of the cochlea, table 38,
figures 4 to 12.
on the rat, while in the cat they diminish from birth till thirty
days though irregularly.
The absolute values are greater for the rabbit than for the
rat during the earlier stage, but afterwards they are similar.
68
In the cat the early data give values similar to those for the rat,
but the later values are lower.
Bottcher's observations ('69) on the cat, calf, and sheep also
give larger values than mine. In the cat the greater ridge has
an average height of 75 [x and in both the others of 90 \L. Therefore,
even in the same animal (cat) there are large differences in the
data presented by different authors.
TABLE 39 Condensed
Ratois of the greatest height of the greater epithelial ridge (resp. of the inner supporting cells) according to the turns of the cochlea on age
Average age
Average body
weight
RATIOS BETWEEB TURNS
I-II
i-in
I-IV
days
grams
1
5
1 :1.0
1 1.0
1 :0.9
8
11
: 1.0
1.1
: 1.2
18
21
:1.1
1.2
:1.3
213
138
:1.0
1.2
:1.3
TABLE 40
Greatest height of the greater epithelial ridge measured through the inner supporting
cells, in p. (Retzius)
RABBIT
CAT
Age
days
Basal
turn
Middle
turn
Apical
turn
Average
turn
Basal
turn
Middle
turn
Apical
turn
Average
turn
New-born
78
99
90
89
45
75
6S
63
2
60
90
90
80
3
40
84
7
51
68
63
61
40
54
63
52
10
36
54
56
49
11
50
58
66
58
14
51
51
51
51
30
30
.
45
45
40
Gottstein ('72) thinks that the greater epithelial ridge does
not diminish its height for some time after birth, but through
the outward development of the labium tympanicum, and in
addition to this through the growth of the labium vestibulare,
the sulcus spiralis internus arises. He does not give measurements.
GROWTH OF THE INNER EAR OF ALBINO RAT 69
His idea was strongly opposed by Bottcher ( 72) and my results
are also opposed to Gottstein's view.
8. The radial distance between the labium vestibulare and the
habenula perforata. The purpose of this measurement is to
determine how the habenula perforata stands in relation to its
surroundings during the development of the cochlea. The measurements of this distance is difficult. During the earlier stages,
the labium vestibulare is quite undeveloped, especially in the
upper turns. At birth we see on the inner surface of the greater
epithelial ridge a small prominence under which the epithelial
cells are short and pressed together so that the nuclei seem to be
arranged in several rows (fig. 4). This appearance is due to the
invasion of the subjacent connective tissue into the epithelium.
Thus the vestibular lip arises. We do not see a furrow at this
time and cannot use the top of the furrow as a point for measuring
as did Hensen ('63) in the ox and Bottcher ('69); in the embryo cat). To the measure the distance between the insertion of
Reissner's membrane and the habenula perforata has no meaning
for my purpose, because the length of the limbus laminae spiralis
changes with age.
Thus I have measured the distance between the small epithelial
prominence on the axial side of the greater ridge, corresponding
to the edge of the labium vestibulare, and the habenula perforata.
In table 41 (charts 17 and 18) are given the -values of the radial
distance between the labium vestibulare and the habenula
perforata. At the foot of the last column are given the ratios
from 1 to 546, 9 to 546, and 20 to 546 days. As we see, the
values are a little bit smaller at the earlier stage. After nine
days they are almost the same in every stage. The small differences at the earlier and later stages are probably due to the
retarded development of the labium vestibulare.
When we consider the values for this distance in each turn,
it is evident that these increase from base to apex. In the condensed table 42 this relation is shown.
Hensen ('63) finds that the distance from the top of the furrow
to the habenula perforata is in the fetal calf and in the ox the
70
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
same, 255 [x. He considers the holes of the habenula as a ' punctum
fixum. ' Bottcher ('69, 72) agrees with Hensen and gets in the
cat embryo and the adult cat the following values (table 43).
TABLE 41
Radial distance between the labium veslibulare and the habenula perforata on age
(charts 17 and 18)
AGE
BODY WEIGHT
TURNS OP THE COCHLEA M
I
II
III
IV
Average
days
grams
1
5
100
108
120
130
115
3
8
80
110
130
137
114
6
11
82
105
135
137
115
9
10
83
108
137
145
118
12
13
80
102
139
148
117
15
13
82
107
144
157
122
20
29
84
106
146
153
122
25
36
82
105
147
150
121
50
59
82
104
137
147
118
100
112
80
103
151
154
122
150
183
80
107
141
144
118
257
137
83
105
143
150
120
366
181
79
105
135
149
117
546
255
79
105
143
150
119
Ratios 1 546 days
9546 "
20546 "
1.0
1.0
1.0
TABLE 42 Condensed
Ratios of the radial distance between the labium vestibulare and the habenula
perforata according to turns of the cochlea
RATIOS BETWEEN TURNS
AVEKAGE AGE
WEIGHT
I-II
I-II I
I-IV
days
grams
1
5
1 1.1
1 1.2
1 1.3
5
10
1.3
1.6
1.8
141
93
1.3
1.7
1.8
Comparing the results of both Hensen and Bottcher with
my own, the values obtained by Hensen are large, as would
be expected in the larger animal. The cat and rat however,
give similar values. We conclude, therefore, that broadly speak
GROWTH OF THE INNER EAR OF ALBINO RAT
71
ing, the habenula perforata is to be considered as a 'punctum fixurn, 'at least after birth.
9. The radial distance be'.ween the labium vestibulare and the
inner edge of the head of the inner pillar cell To measure the
140
120
1OO
AGE DAYS
25
50
50 1OO 2OO 3OO 40O 500
Chart 17 The radial distance between labium vestibulare and the habenula
perforata, table 41, figure 10.
i cr\
loO
it
/
'
a
: _
*
- v
/
^
.
/
>
\
_
140
A
it
*
k
;
^
- !
_
:
/
/
12O
,*
\t\f\
y
~
~
1UO
1
Qf\
1
o
~j
^
(
^
a
ou
fj
i
g
/A
f*f\
|
2
Y
25
50
Chart 18 The radial distance between labium vestibulare and the habenula
perforata according to the turns of the cochlea, table 41.
radial breadth from the labium vestibulare to the inner edge
of the head of the inner pillar cell, I have used, at earlier stages,
as in the preceding chapter, the same small prominence as an
inner fixed point (fig. 4). In table 44 (chart 19) are given the
values for this radial distance according to age. At the bottom
of the last column are given the ratios from 1 to 9, 1 to 546
72
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
TABLE 43
Distance between labium vestibulare and habenula perforata in n (Bottcher)
PLACE OF
CAT EMBRYO 9 CM.
CAT EMBRYO 11 .5
CAT THREE DAYS
ADULT CAT
MEASUREMENT
LONG
CM. LONG
OLD
I turn
120
120
120
100
II turn
130
130
130
110
III turn
150
140
140
130
TABLE 44
Radial distance between the labium veslibulare and the inner edge of the head of the
inner pillar cell on age (chart 19)
AGE
BODY WEIGHT
TURNS OF THE COCHLEA M
I
II
ill
IV
Average
days
grams
1
5
111
126
138
130
126
3
8
84
118
150
170
131
6
11
88
119
159
180
136
9
10
94
131
168
179
143
12
13
69
97
138
156
115
15
13!
",' 66
103
137
149
114
20
29
66
103
137
148
114
25
36
65
100
136
148
112
50
59
61
98
129
144
108
100
112
64
99
139
153
114
150
183
60
99
129
143
108
257
137
67
100
134
149
113
366
181
60
102
130
151
111
546
255
55 :..
99
128
143
106
Ratios 1 9 days
1546 "
12546 "
1.1
0.8
0.9
TABLE 45 Condensed
Ratios of the radial distance between the habenula perforata and the inner edge of
the head of the inner pillar cell according to the turns of
the cochlea on age
KATIOS BETWEEN TURNS
AVERAGE AGE
WEIGHT
I-II
I-HI
I-IV
days
grams
1
5
1 1.1
1 \.9
1 1.2
6
10
1.4
1.8
2.0
154
102
1.5
2.1
2.3
GROWTH OF THE INNER EAR OF ALBINO RAT
73
and 12 to 546 days of age. As the table shows, the values increase in general from birth to nine days; therefore, the surface
of the greater epithelial thickening from the labium vestibulare
to its outer boundary becomes, during the earlier stage, wider
and wider, then decreases sharply, and after that continuously
but slowly. This sudden diminishing of the distance has a very
intimate relation with the change in the form of the papilla
spiralis at this stage of development.
This point I will discuss later.
That the values increase from the base to the apex first rapidly
and later less rapidly, is also to be seen here. Table 45 shows this
relation clearly. It is remarkable, however, that the ratio becomes
140
12O
1OO
AGE DAYS'
25
50 50 1OO 2OO 300 400 50O
Chart 19 The radial distance between the labium vestibulare and the
inner edge of the head of the inner pillar cell, table 44.
at each turn larger with age, although the absolute value is
after nine days generally smaller than at the preceding age.
Therefore, we see that the diminution of the distance after
nine days is largest in the basal turn and smallest in the apical.
Hensen ('63) asserts that there is a movement axialward of
the organ of Corti (resp. the head of the pillar cell), but gives no
measurements. Neither Bottcher nor Retzius measured this
distance. Prentiss ('13, page 445) states that "the distance
between the inner angle of the cochlea and the pillar cells, two
definite points, may be measured with considerable accuracy
and shows no important change in the position of the spiral
organ from the 13 cm. to the 18.5 cm. stage, nor later in the
new born animal" (pig) But he also does not record his measurements.
74
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
Hardesty ('15, p. 54) says "that the space occupied by the
width of the greater epithelial ridge increases throughout the
coils of the cochlea up to pigs of 15 to 16 cm., and thereafter
it begins to decrease very perceptibly." He measured the
width ''from the membrana propria of the epithelium of the
greater ridge, at its most axial extension under Huschke's teeth,
to the apical end of the inner hair cell of the spiral organ. " The
TABLE 46
Vertical distance from the membrana basilaris to the surface of the pillar cells on
age (chart 20}
TURNS OF THE COCHLEA M
AGE
BODY WEIGHT
I
II
ill
IV
Average
days
grams
1
5
35
36
39
36
37
3
8
30
29
29
29
29
6
11
29
32
31
29
30
9
10
32
33
35
36
34
12
13
41
45
50
52
47
15
13
44
48
53
57
51
20
29
53
57
67
71
62
25
36
55
56
66
68
61
50
59
53
55
67
68
61
100
112
53
54
64
67
60
150
183
52
54
63
66
59
257
137
53
56
63
69
60
366
181
51
56
66
67
60
546
255
52
55
62
66
59
Ratios 1 12 days 1-1.3
1 20 " 1.7
1546 " 1.6
12546 " 13
20546 " 1.0
method of measurement differs from mine, so the results cannot
be compared directly. While the distance in the rat increases
to nine days of age, that in the pig decreases perceptibly in
fetuses more than 16 cm. long.
According to Hardesty ('15, p. 55). "the decrease in the I
and III half turns may be as much as one-third of the width
of the greater ridge when at its maximum size and activity. "
And "after the tectorial membrane is about completely produced,
GROWTH OF THE INNER EAR OF ALBINO RAT
75
and while the spiral organ is enlarging, the inner hair cells, and
therefore the organ, may be moved in the apical coil of the
cochlea axialward a distance of about half the maximum width
of the greater epithelial ridge, "
The differences of the values in the rat at 9 and 546 days are
in the basal and apical turn about the same, 39 and 36 n, respectively (table 44). Thus while the inner edge of the inner
pillar cell approaches at 546 days in the basal turn by as much
as 41 per cent of the distance present at nine days, that in the
80
60
40
20
AGE.qAYS
25 50 5Q 1QO 2OO 300 4OO 5OO
Chart 20 The vertical distance from the membrana basilaris to the surface
of the pillar cells, table 46, figure 1, 1-1.
apex moves only 20 per cent inward in old age. This result
is the reverse of that obtained in the pig by Hardesty. The
reason for this contradiction I will discuss later.
10. The vertical distance from the membrane basilaris to the
summit of the pillar cells. The method of getting the vertical
distance from the membrana basilaris to the surface of the
pillar cells is shown in figure 1, line 1-1. In table 46 (chart 20)
are given the values thus obtained. At the foot of the last
column are given the ratios of this distance at 1 to 12, 1 to 20,
1 to 546, 12 to 546, and 20 to 546 days. The average value is
relatively large at birth, it diminishes at three days, then increases
more rapidly to twenty days. After this it decreases very slowly.
The maximum height of the arch of Corti is at twenty days of
76
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
age. Comparing the values for the height in each turn, we find
that from nine days they increase from the basal to the apical
turn. This relation can be easily seen in table 47.
Retzius ( '84) gives in the rabbit and cat the following values
(table 48).
TABLE 47 Condensed
Ratios of the vertical distance from the membrana basilaris to the surface of the
pillar cells according to the turns of the cochlea
RATIOS BETWEEN TURNS
AVERAGE BODY
AVERAGE AGE
WEIGHT
I-II
i-ni
I-IV
days
grams
1
5
1 :1.0
1 : 1.1
1 : 1.0
1
11
: 1.1
: 1.1
: 1.1
18
21
: 1.1
: 1.2
: 1.3
213
138
: 1.0
: 1.2
: 1.3
TABLE 48
Vertical distance from the membrana basilaris to the summit of the pillar cells
BABBIT
CAT
Age
Basal
turn
Middle
turn
Apical
turn
Average
Basal
turn
Middle
turn
Apical
turn
Average
days
New-born
45
70
61
59
45
60
48
51
2
45
69
40
51
3
39
60
7
46
60
60
55
45
47
50
44
10
45
69
69
61
11
JK
50
60
42
51
14
45
57
66
56
30
' }'
33
51
57
47
Table 48 shows that the height of the arch of Corti in the
rabbit approximates that in the rat, though there are considerable
differences in the earlier stages. In the former the arch of Corti
develops after: birth only a little, and is therefore more precocious than in the rat. In the cat the same relation is to be
seen, but the absolute values in the latter animal are smaller
than in either the rabbit or the rat.
GROWTH OF THE INNER EAR OF ALBINO RAT 77
11. The greatest height of the tunnel of Corti. Some authors
have reported in several animals the appearance of the tunnel
of Corti just after birth, or even in later intrauterine life. In
the rat, however, it first appears through all the turns after
the ninth day. Sometimes we see it at nine days in the lower
turn, though not yet in the upper. The method of measuring
the height is shown in figure 1, line 1-1'. Table 49 (charts 21
and 22) gives the values for the greatest height of the tunnel of
Corti. At the foot of the last column are given the ratios from
12 to 25, 12 to 546, and 25 to 546 days.
As the table shows, the space appears in all the turns at twelve
days and has considerable height. This increases to twenty-five
days, than decreases very slowly. This increase and decrease
correspond to the changes in the distance of the summit of the
pillar cells from the basilar membrane.
When we consider the height in each coil of the cochlea, we
find the value increases from the base to the apex, first rapidly
then slowly. In table 50 this relation is clearly shown.
Retzius ('84) gives the values for the adult rabbit, man and
cat (one month) as follows (table 51).
According to this table, the average height is in the adult
man, cat, and rabbit somewhat less than in the rat.
12. The height of the papilla spiralis at the third series of
the outer hair cells. The measurements were taken along the
line 2-2 shown in figure 1. The growth of this vertical height
depends not only upon the increase of the length of the corresponding outer hair cell, but chiefly upon the development of
the Deiters' cells, especially of the outermost row, and of the
sustentacular cells of Hensen.
In table 52 (charts 23 and 24) are given the values for this
vertical height of the papilla spiralis at the third series of the
outer hair cells according to age. At the bottom of the last
column are the ratios at 1 to 12, 1 to 20, 1 to 546, and 20 to 546
days. The heights decrease at three days, but increase from
nine to twelve days very rapidly, nearly doubling their minimal
values, and reach a maximum at twenty days. After that time
they decrease very gradually to the end of the record. There
78
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
TABLE 49
Greatest height of the tunnel of Corti on age (charts 21 and 22}
AGE
BODY WEIGHT
TURNS OP THE COCHLEA M
I
II
ill
IV
Average
days
grams
1
5
3
8
6
11
9 1
10
12
13
29
33
39
37
35
15
13
31
34
42
46
38
20
29
37
42
52
56
47
25
36
39
41
54
56
48
50
59
38
41
53
57
47
100
112
38
43
51
56
47
150
183
37
41
49
54
45
257
137
38
43
51
56
47
366
181
37
41
52
53
46
546
255
36
39
48
53
44
Ratios 12 25 days
12546 "
25546 "
1.4
1.3
0.9
1 In one case nine days old which could hear the space was found
through all the turns of the cochlea.
TABLE 50 Condensed
Ratios of the greatest height of the tunnel of Corti according to the turns of the
cochlea on age
, RATIOS BETWEEN TURNS
AVERAGE BOOT
AVERAGE AGE
WEIGHT
I-II
i-ni
I-IV
days
grams
12
13
1 : 1.1
1 1.3
1 1.3
18
21
:1.1
1.4
1.5
213
138
:1.1
1.3
1.4
TABLE 51
The greatest height of the tunnel of Corti in n (Retzius)
RABBIT
CAT (one month)
MAN
Basal
Middle
Apical
Average
Basal
Middle
Apical
Average
Basal
Middle
Apical
Average
30
39
36
35
18
37
36
30
28
45
49
41
GROWTH OF THE INNER EAR OF ZLBINO RAT
79
fore, the difference between the ratios at 1 to 20 and 1 to 546
days is very small.
At twelve days and after, the values for the height increase in
passing from the base to the apex, at first rapidly, then more
slowly. In the earlier stages this relation is obscure or reversed.
60
40
20
n
1
^
JS.
/
x
G
E
c
A
Y5
25
50
5O 10O 20O 300 400 5OO
Chart 21 The greatest height of the tunnel of Corti, table 49, figure 1, 1-1
60
40
/(
^'
'
__ (
_
,
*
>
'
L
^~"
1
a
/
n
A
>/c
u
Y
2
5
5
5<
D
II
~\c
J\.
)
2(
)C
)
3(
DC
)
4
4C
)0
5C
)0
Chart 22 The greatest height of the tunnel of Corti, according to the turns
of the cochlea, table 49. .
In the condensed table 53 are given the ratios in each turn.
While the ratio of each turn before eight days is about 1:1.1,
and between turns I and II remains constant in the later age,
that for I to III and I to IV is at 18 and 213 days decidedly
larger. Therefore, the increase of the height is most marked
in the III and IV turn, as shown in chart 24.
TABLE 52
Height of the papilla spiralis at the third series of outer hair cells on age
(charts 23 and 24)
AGE
BODY WEIGHT
TURNS OF THE COCHLEA M
I
II
III
IV
Average
days
grams
1
5
35
35
39
28
34
3
8
22
23
25
26
24
6
11
25
24
25
23
24
9
10
28
28
27
28
28
12
13
40
49
54
56
50
15
13
46
53
65
66
58
20
29
56
61
76
81
69
25
36
56
61
76
78
68
50
59
53
59
78
80
68
100
112
54
59
74
79
67
150
183
55
57
75
77
66
257
137
54
59
74
81
67
366
181
5?
58
75
78
66
546
255
52
58
72
75
64
Ratios 1 12 days 1 1.5
1 20 " 2.0
1546 " 1.9
20546 " 0.9
TABLE 53 Condensed
Ratios of the height of the papilla spiralis at the third series of outer hair cells
according to the turns of the cochlea on age
AVERAGE AGE
AVERAGE BODY
WEIGHT
BATIOS BETWEEN TURNS
I-II
i-ni
I-IV
days
grams
1
5
1 :1.0
1 :1.1
1 0.8
8
11
:1.1
: 1.1
1.1
18
21
: 1.1
: 1.4
1.5
213
138
: 1.1
:1.4
1.5
TABLE 54
Height of the papilla spiralis at the third scries of outer hair cells in n (Retzius)
BABBIT
CAT
AGE
Basal
turn
Middle
turn
Apical
turn
Average
Basal
turn
Middle
turn
Apical
turn
Average
days
New-born
48
70
60
59
45
60
45
50
2
45
70
54
56
3
40
58
7
54
69
66
63
42
5<
48
49
10
42
86
84
71
11
60
72
42
58
14
60
87
90
79
30
36
57
70
54
80
GROWTH OF THE INNER EAR OF ALBINO RAT
81
Retzius ('84) finds in the rabbit and cat the [values for this
height given in (table 54).
Comparing these average numbers with mine, it appears that
the height in the rabbit is greater, and in the cat smaller than
u
70
5O
30
10
k
AGE
o
25 5O 50 |OO 2OO 3OO 40O 5OO
Chart 23 The height of the papilla spiralis at the third series of the outer
hair cells, table 52, figure 1, 2-2.
90
70
50
30
10
AGE DA.YS
O
25
50
5O 1OO 2OO 3OO 4OO 5OO
Chart 24 The height of the papilla spiralis at the third series of the outer
hair cells, according to the turns of the cochlea, table 52.
in the rat. In both animals the values increase rapidly at ten
to eleven days of age, as in the albino rat, but the height in these
animals is at the earlier stage almost twice as large as in the rat.
Hardesty ('15) measured the thickness of the organ of Corti in
82
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
the pig in a somewhat different way, using the vertical line from
the basilar membrane proper through the m'ddle of the outer
hair cell to the surface of the organ, and found the increase in
thickness to take place most rapidly at the stages before full term,
though it seems to continue after birth. I have not made cor
TABLE 55
Greatest height of Hensen's supporting cells on age (chart 25)
AGE
BODY WEIGHT
TURNS OP THE COCHLEA M
1
II
III
IV
Average
days
grams
I
5
36
36
38
31
35
3
8
18
21
21
24
21
6
11
21
20
21
18
20
9
10
20
23
23
24
23
12
13
40
49
56
58
51
15
13
44
56
69
72
60
20
29
64
64
86
87
75
25
36
69
71
84
86
78
50
59
71
74
87
89
81
100
112
77
. 78
87
89
83
150
183
76
77
<3
93
85
257
137
81
83
89
89
86
366
181
82
83
89
91
86
546
255
79
79
92
93
86
Ratios 1 6 days
1 12
1 20
1546
6 12
6 20
6546
12 20
12546
20546
0.6
1.5
2.1
2.5
2.6
3.8
4.3
1.5
1.7
1.1
responding studies on the rat. In the latter animal, however,
the rapid increase usually appears at twelve days of age, when
the animal as a rule first responds to auditory stimuli, and thus
we have a correlation between the development of the organ
and the beginning of the function, which will be discussed later.
In the case of one rat that could hear at nine days this change
had already occurred.
GROWTH OF THE INNER EAR OF ALBINO RAT
83
13. The greatest height of Hensen's supporting cells. The older
authors (Kolliker and others) thought that the arch of Corti
marks the highest point of the papilla which slopes from this
point gradually outward to the cells of the zona pectinata.
Against this erroneous idea Hensen ('63) first published observations showing that the highest point is in the papilla which
ascends laterally from the outer hair cells, and then slopes
abruptly and passes over to the cells of the sulcus spiralis externus.
We term this prominence Hensen's prominence and the cells,
Hensen's supporting cells. The measurements of the height of
90
M
70
50
30
\c\
.-<
s
l
1
/
1
/
I'
i
1
|
\
j
\
1
\
jj
GE
i
T
25 50 50 100 200 300 400 50O
Chart 25 The greatest height of Hensen's supporting cells, table 55.
these cells were made along 3 3 in figure 1. Table 55 (chart
25) shows the values for the greatest vertical height of these
supporting cells according to age. At the foot of the last column
are given the ratios from 1 to 6, 1 to 12, 1 to 20, 1 to 546, 6 to 12,
6 to 20, 6 to 546, 12 to 20, 12 to 546, and 20 to 546 days. The
values diminish at the earlier stage from birth to six or nine days.
At twelve days they increase suddenly, more than doubling.
After that they increase to old age, rapidly up to twenty days
and then slowly. Here also the height increases from the base
to the apex, the most marked increase occurring between turns
II and III. In table 56 this relation is clearly shown. Retzius
('84) gets values of this height in the rabbit and cat as follows
(table 57).
84 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
In both the rabbit and the cat the height increases at ten to
eleven days very considerably, as it does in the rat. Only
there is a large difference in the absolute values for the
three animals, these being largest in the rabbit and smallest
in the cat. The final average values in the cat are nearly the
same as those in the rat at the same age.
Kolmer ('07) finds in the calf the value in the highest point
of the organ of Corti in the region of the innermost Hensen's
cells as follows:
In the basal turn, 84 [A
In the second turn, 90 JJL
In the third turn, 105 [JL
Average, 93 [i.
Hensen ('63) gives in man the average height of the papilla
as 90 (JL in the hamulus and 60 [j. in the radix. Thus the height
of Hensen's cells is different in different animals.
When we consider the growth in the height of Hensen's cells
we can picture the change of the form in the papilla spiralis.
As shown already, the height of the pillar cells is largest at the
earlier stage, when the papilla has its highest point at the summit
of the arch of Corti, and slopes downward to the Hensen's cells.
But at twelve days the form is reversed, and the highest point
is in Hensen's prominence from which the surface slopes inward
more or less steeply to the surface of the pillar cells and the
inner supporting cells. Thus the surface of the papilla does
not run parallel to the basilar membrane, but makes with it a
sharp angle opening outward. This angle has been measured.
14- The angle subtended by the extension of the surface of the
lamina relicularis with the extended plane of the membrana basilaris.
As just stated, the lamina reticularis after the earlier stages
is not parallel to the membrana basilaris, but forms an angle
with it. The measurements of this angle , were taken as
shown in lines 4~4' i n figure 1. In table 58 (chart 26) are given
the values for the angle in degrees. Before nine days there is
no appreciable angle. From twelve to twenty days the angle
increases rather rapidly, and after twenty days continuously
but slowly. The ratio at the bottom of the last column shows
this clearly.
GROWTH OF THE INNER EAR OF ALBINO RAT
85
Comparing the values of the angle in each turn according to
age, there is no clear evidence that it increases from base to apex,
though it tends to be largest in turn III and next largest in turn
II. The condensed table 59 shows these relations. Retzius
( ; 84) finds this angle in the rabbit and cat to be as in table 60.
TABLE 56 Condensed
Ratios of the greatest height of Hensen's supporting cells according to the turns of
the cochlea
RATIOS BETWEEN SUCCESSIVE TURNS
AVERAGE AGE
AVERAGE BODY
WEIGHT
1
I-II
I-III
I-IV
days
grams
1
5
1 1.0
1 1.1
1 0.9
8
11
1.1
1.2
1.2
18
21
1.1
1.4
1.5
213
138
1.0
1.2
1.2
TABLE 57
Greatest height of Hensen's supporting cells in M (Retzius)
RABBIT
CAT
Age
Days
Basal
turn
Middle
Apical
Average
Basal
Middle
Apical
Average
Xew-born
38?
60?
50?
49?
45
50
39
45
2
55?
60?
3
39
54
7
48
81
67
65
57
50
40
49
10
105
125
105
112
11
75
78
45
66
14
150
120
30
50
69
95
71
Retzius also finds in man in the basal turn 25, in the middle
35, and in the apical 23. Thus the angle always increases with
age, but has different absolute values in different mammals and
always tends to be greater in the middle turns.
15. Lengths of the inner and outer pillar cells. The measurements of length were taken as shown by lines 1-1, and 2-2 as in
figure 2. This does not give the total length, but the length
from the base to the point, just below the joint. As is well
86
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
TABLE 58
Angle of the lamina reticularis with the plane of Ihe membrana basilaris in
degrees, 6 (chart 26}
TURNS OF THE COCHLEA DEGREES
AGE
BODY WEIGHT
I
II
III
IV
Average
days
grams
1
5
3
8
6
11
9
10
12
13
7
12
13
9
10
15
13
11
14
13
13
13
20
29
15
13
11
11
13
25
36
14
14
13
13
14
50
59
15
15
17
11
15
100
112
15
14
16
14
15
150
183
15
15
19
17
17
257
137
13
15
18
17
16
366
181
16
15
16
16
16
546
255
16
16
17
17
17
Vertical averages
13.7
14.3
15.3
13.8
Ratios 12 20 days 1 : 1.3
12546 " :1.7
TABLE 59 Condensed
Ratios of the angle of the lamina reticularis with the plane of the membrana basilaris
according to the turns of the cochlea
RATIOS BETWEEN TURNS
AVERAGE AGE
AVERVGE BODY
WEIGHT
I-II
I-II I
I- IV
days
12
grams
13
1 1.7
1 1.9
1 : 1.3
18
21
1.0
0.9
:0.9
213
138
1.0
1.2
:1.0
TABLE 60
Angle of the lamina reticutaris with the plane of the membrana basilaris in degrees
(Retzius)
Age
Basal
turn
Middle
turn
Apical
turn
Average
Basal
turn
Middle
turn
Apical
turn
Average
days
New-born
5?
8?
5? 8?
2
3
5? 8?
7
17
19
11
5
5
10
10
20
30
23
24
11
20
1020
14
25
50
45
40
30
18
23
20
20
GROWTH OF THE INNER EAR OF ALBINO RAT
87
known, the inner and outer pillar cells when mature show a more
or less S-shaped curvature, though they are straighter in the
earlier stages. Thus the length as measured in the adult cochlea
is somewhat smaller than the natural lengths.
DEGREES
18
15
12
25
50
5O 1OO 20O 300 40O 500
Chart 26 The angle subtended by the extension of the lamina relicularis
with the extended plane of the membrana basilaris, in degrees, table 58, fieure 1
4-4', 9
In table 61 (charts 27 to 32) is given the values for the lengths
of the inner and outer pillar cells according to age. At first we
shall consider the average values for the length of the inner
and outer pillar cells taken together. This length diminishes
at three days. From three to twelve days it increases rapidly,
88
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
and from twelve to twenty days more slowly. After twenty
days it decreases a little. The ratios at the bottom of the last
column show these relations. The familiar fact, that the length
increases from the base to the apex is clearly shown in chart 28.
TABLE 61
Lengths of the inner and outer pillar cells (without head) measured from the footplate
on the membrana basilaris to the point directly below the junction
(charts 27 to 32)
AOE
BODY
WEIGHT
INNER PILLAR
OUTER PILLAR
Combined
Average
Turns of the cochlea M
Turns of the cochlea M
I
II
ill
IV
Average
I
II ill
IV
Average
days
gms
1
5
28
29
29
29
29
24
27
27
26
26
28
3
8
26
23
26
23
25
19
20
20
21
20
23
6
11
35
36
36
37
36
21
26
27
26
25
31
9
10
35
39
41
40
39
26
26
29
29
28
34
12
13
33
38
44
44
40
46
59
72
72
62
51
15
13
34
38
48
51
43
44
59
74
78
64
54
20
29
43
47
56
60
52
56
65
79
83
71
62
25
36
43
47
56
60
52
53
64
80
84
70
61
50
59
42
44
55
61
51
52
64
79
84
70
*61
100
112
42
44
53
58
49
52
62
79
84
69
59
150
183
41
43
54
59
49
51
64
76
85
69
59
257
137
40
44
53
60
49
53
64
75
85
69
59
366
181
39
45
53
59
48
50
64
78
83
69
59
546
255
41
44
53
58
49
49
64
78
83
69
59
Ratios 1- 12 days
1 1.4
1 :2.4
1 : 1.8
1- 20 "
1.8
2.7
:2.2
1-546 "
1.7
2.7
:2.1
20-546 "
0.9
1.0
: 1.0
When we calculate the average values of the inner and outer
pillar cells from Retzius table ('84), we get the following (table
62). .
TABLE 62
Combined lengths of the inner and outer pillars from the foot plate to a point
directly below the junction in n (Retzius)
RABBIT (adult)
CAT (adult)
MAN (adult)
Basal
turn
Middle
turn
Apical
turn
Average
turn
Basal
turn
Middle
turn
Apical
turn
Average
Basal
turn
Middle
turn
Apical
turn
Average
66
85
78
76
55
75
73
67
55
84
87
75
GROWTH OF THE INNER EAR OF ALBINO RAT
89
70
50
30
10
25
50
5O 1OO 2OO 300 4OO 5OO
Chart 27 The length of inner and outer pillar cells combined, without
head, measured from the foot plate on the membrana basilaris to the point
directly below the junction, table 61, figure 2, /-/, 2-2.
80
w.q A re
25 50 50 JOO 200 300 4OO 5OO
Chart 28 The length of inner and outer pillar cells combined, without
head, measured from the foot plate on the membrana basilaris to the point
directly below the junction, according to the turns of the cochlea, table 61.
,u
50
30
in
s
r -'
J
GE
D
A
TO
25
5O
2OO
5(X)
Chart 29 The length of inner pillar cell without head, table 61, figure 2, 1-1.
90 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
As table 62 shows, the values in these mammals are larger
than those in the albino rat a result which fits with our previous
observations.
When we consider the length of the inner pillar cells alone,
we see that the values (chart 29) here also increases from three
days to twenty days, but not so largely as in the combined values
of the inner and outer pillar cells. After twenty days the values
for the inner pillar cells decrease slightly. This relation is shown
by the ratios at the bottom of the corresponding column. That
the increase progresses from the base to the apex, being most
marked in turn III, is illustrated in chart 30. The condensed
table 63 shows those relations also. The one-day-old rat is an
exception.
We turn now to the growth in the length of the outer pillar
cells. As we see in table 61 (chart 31), the length of the outer
pillar cell does not increase so much from one to nine days as the
inner pillar cell did. At twelve days, however, the increase in
length is very marked, that is, 2.2 times as much as at nine days.
After the outer pillar cell reaches its maximum at twenty
days, it decreases only slightly with advancing age. The ratios
at the bottom of the corresponding column show this relation
clearly. The length increases from base to apex, though this
relation is not well established until twelve days, as shown in
table 61 and chart 32. The ratios of the outer pillar cells according to the turns of the cochlea are shown in table 64.
The inner and outer pillar cells show marked differences in
their growth. While at the earlier ages the length of the inner
is greater than that of the outer, yet after twelve days this
relation is reversed. Moreover, from nine to twelve days the
growth is gradual in the inner pillar cells, but rapid in the outer.
The condensed table 65 shows the values for the length of the
inner and outer pillar cells separately. In the last column are
given the ratios between them.
In the accompanying table 66 I have compared the values
obtained in the rat with those given by other authors.
As table 66 shows, the absolute values differ in various animals.
However, the ratios between the values for the inner and outer
eu
A*
fir\
ou
/
,
k-
2
{/
""
:,
A f\
i
j'f
,
=-fl
*HJ
A
-X
v
J
*-i
O/"
i
20
ft
p
IT
L
P
L
ft
vcj
f\
u
2
o
25
50 50 10O 200 3OO 4OO 50O
Chart 30 The length of the inner pillar cell without head, according to
the turns of the cochlea, table 61.
80
M
60
40
20
f\
/
f-'
1
1
1
1
,
.
.'"1
\
AGE
i i
DAY
25
50
5O 1OO 200 300 4OO 50O
Chart 31 The length of outer pillar cells without head, table 61, figure 2,
IVAJ
M
RH
t
ou
y
~
"~
^
^
ar\
/
*
^
~
~
^
^
~
* *
"'
"~
" *
oU
<k "
k <
~^
_,
>
_
*
-~
Af\
;
n
t *
oo
^U
r
<~~
A
k/C
n
(j
1OT
25 50 50 1OO -OO 3OO 4OO 5OO
Chart 32 The length of outer pillar cells without head, according to the
turns of the cochlea, table 61.
91
92
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
TABLE 63 Condensed
Ratios of the length of the inner pillar cells according to the turns of the cochlea
AVERAGE AGE
AVERAGE BOOT
WEIGHT
RATIOS BETWEEN TURNS
I-II
I-II I
I-IV
days
1
grams
5
1 1.0
1 1.0
1 1.0
8
11
1.1
1.2
1.1
18
21
1.1
1.3
1.4
213
138
1.1
1.3
1.4
TABLE 64 Condensed
Ratios of the length of the outer pillar cells according to the turns of the cochlea
AVERAGE AGE
AVERAGE BODY
WEIGHT
RATIOS
BETWEEN TURNS
I-II
I-II I
I- IV
days
1
grams
5
1 : 1.1
1 1.1
1 1.0
8
11
:1.2
1.3
1.3
18
21
: 1.2
1.5
1.6
213
138
: 1.3
1.5
1.6
TABLE 65 Condensed
Comparison of the average length of the inner and outer pillar-cellswithout
head.
AVERAGE LENGTH OF PILLAR CELLS
AVERAGE AGE
AVERAGE BODY
WITHOUT HEAD
RATIOS OF INNER
\V V T ( ' H T
TO OUTER
Inner
Outer
days
grams
1
5
29
26
1 :1.0
8
11
35
34
:1.0
18
21
48
68
:1.4
213
13S
50
69.
: 1.4
pillar cells are smallest in man and in the rat and alike in the
other two forms, Retzius ('84). Hensen ('63) states that in the
base of the human cochlea both pillar cells are equally long.
Later, Pritchard ('78) supported this observation. In the
literature, however, no one except these two authors report the
inner and outer pillar cells in the base of the adult cochlea as
equal in length, but the inner is always stated to be shorter than
the outer. We may therefore say that most authors agree that
the inner pillar cells are at earlier stages longer than the outer,
then they become equal, and finally the outer surpass the inner.
GROWTH OF THE INNER EAR OF ALfcINO RAT
93
TABLE 66
Lengths of inner and outer pillars in several mammals according to different authors.
Measurements in n
INNER PILLAR
OUTER PILLAR
Authors
Animals
Basal
turn
Middle
Apical
Av.
B.
M.
A.
Av.
Ratio
Corti
Mammals
30
30
34
31
4549
54
58
69
57
1:1.8
Hensen
Man
48
86
(Hamul
us)
48
98
(Hamulus)
Ret
zius
Wada
Rabbit
56
60
60
59
75
110
95
93
:l.
Cat
41
54
57
51
68
62
95
89
84
:1.6
Man
48
68
70
62
100
103
88
:l.t
Albino
rat
after 20
days
I
41
II
45
III
54
IV
59
50
I
52
II
64
III
78
IV
84
70
-.1.4
16. Inner and outer hair cells. For a long time the inner
and the outer hair cells have been regarded as the most important
elements in the papilla spiralis. As these sense cells have a
delicate histological structure which is readily altered, the
systematic study of their growth, especially after the appearance
of hearing, is a difficult matter. Though there are some observations
on the length of these cells, detailed studies on their growth
have not been made heretofore. I have therefore endeavored
to follow the changes of their size during the postnatal period.
It is first necessary to determine the form of these cells. They
are generally described as cylindrical, but this description is
inexact. Moreover, the inner and outer hair cells are somewhat
different in shape. The former has on the surface a large oval
terminal disk, which is wide hi the spiral and narrow in the
radial direction. This narrows downwards to a thinner neck
which expands into the broader body and terminates in a more
or less round but somewhat pointed irregular end.
94
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
1600
y
1400
1200
1000
800
600
400
2OO
^
/
V
-^
^
^e
=.
'
^
.
k
**
\
i
i
|
i
i
-I
-1
_ ._ .<
4
GE
E
A
^S
ft
25
50
5O 100 2OO 300 4OO 5OO
Chart 33 The weighted volume of inner and outer hair cells combined,
and of their nuclei in cubic micra, tables 67 and 69.
- Weighted volume of inner and outer hair cells combined.
Weighted volume of nuclei of inner and outer hair cells combined.
The outer hair cells have a much more cylindrical form,
their upper terminal disk is not so wide and not round, but
hexagonal. They become a bit thin in the neck, then wide in
the body. Their lower end is rounded. In order, however, to
determine the cell volume, the cell form has been taken as that
of a cylinder. For computation, the average of the diameters
measured in three places, the end disk, neck, and cell body, was
taken as the diameter and the length of the cell as the length of
the cylinder. From these data the volume of the cylinder was
computed.
GROWTH OF THE INNER EAR OF ALBINO RAT
95
In table 67 are given the values for the volume of the cell
bodies in the (1) inner and (3) outer hair cells separately and
the weighted volume of both cells (in the radial section of the
rat cochlea we see one row of inner and three rows of outer
hair cells), according to age.
TABLE 67
Average volumes of the inner and outer hair cells in cubic micro
(charts 33 to 37)
AGE
INNER HAIR CELL
OUTER HAIR CELL
BODY
WGHt
Tu
I
rns of
II
the o
III
achlea
IV
fit
Average
T
I
urns o
II
f the (
III
iwlilr;
IV
l M 3
Average
WEIOHTD
AVERAGE
VOLUME
days
1
gms
5
1255
982
832
631
925
641
626
505
359
533
631
3
6
' 9
12
15
20
8
11
10
13
13
29
1457
1374
1451
1553
1598
1627
1367
1451
1734
1812
1618
1764
1206
1549
1994
1910
1902
1972
913
1221
2013
2157
2128
2189
1236
1399
1798
1858
1812
1888
767
1047
914
818
815
894
928
967
1308
1210
1178
1215
867
1053
1459
1602
1595
1606
571
800
14^8
1499
1559
1960
783
967
1277
1282
1287
1419
896
1075
1407
1426
1418
1536
1293
Av. 11
14
1510
1624
1756
1770
1665
876
1134
1364
1303
1169
25
50
100
150
257
366
546
36
59
112
183
137
181
255
1540
1497
1353
1362
1345
1290
1266
1655
1611
1550
1497
1524
1561
1486
1909
1821
1744
1683
1738
1817
1772
1995
1924
2018
1917
1976
2297
2257
1775
1713
1666
1615
1646
1741
1695
834
805
837
832
873
893
831
1243
1204
1306
1150
1230
1239
1336
1539
1580
1510
1803
1555
1651
1650
1702
1906
1737
1917
1927
1844
1839
1330
1374
1348
1426
1396
1407
1414
1441
1459
1428
1473
1459
1491
1484
Av. 213
138
1379
1555
1783
2055
1693
844
1244
1613
1839
1385
1462
Ratios 1- 12 days
1- 20 "
1-546 "
20-546 "
1- 11 "
11-213 "
1 :2.0
:2.0
0^9
1 :2.4
:2.7
:2.7
:2!2
1 :2.3
:2.4
:2.4
:0.9
:2.0
At first we shall consider the weighted volume for the cell
bodies of the inner and outer hair cells combined (chart 33).
As table 67 shows, the volume increases continuously to the full
size at twenty days. From one to twelve days the increase is
rapid, and after that the volumes are about the same, though
somewhat fluctuating. The ratios show this relation clearly.
96
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
Condensing all age groups into three (averages in table -67),
then the relation changes somewhat. From one to eleven days
the volume increases more than 100 per cent, while from eleven
to 213 days it increases only 13 per cent.
JUUO
1800
1600
1400
1200
10OO
800
6OO
4OO
200
O
f
[
i
\
^_
,
*^
^
"*
.
-M.
-"
^-
4*
X"
**
*
^
- <
r
j
fl
I
^
**'
~~
,
.
~
"'
...
c
A
YS
25 5O 50 1OQ 2OO 300 400 500
Chart 34 The volume of inner hair cells and of their nuclei, tables 67 and 69.
Volume of inner hair cells.
Volume of nuclei of inner hair cells.
The data for the growth of the nuclei of the inner and outer
hair cells are presented in tables 68 and 69. The weighted
values for the diameters of the nuclei (table 68) are large at
the earlier stages, but from twelve days decrease gradually till
GROWTH OF THE INNER EAR OF ALBINO RAT
97
old age. In the three condensed age groups (averages) we see
the decrease of the values from birth till old age. In table 69
are given the values for the volumes of the nuclei, calculated
as spheres (chart 33).
M*
1600
10OO
600
400
V
AGEjDAYS
25
50 50
2OO 3OO 400 500
Chart 35 The volume of inner hair cells, according to the turns of the
cochlea, table 67.
98
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
The weighted values for the volumes of the inner and outer
hair cells in each turn are given in [A 3 table 70. At the bottom
of each column is given the ratio from 1 to 12, 1 to 20, 1 to 546,
and 20 to 546 days of age. While the volume at birth is largest
in turn I and smallest in turn IV, that in turn III is largest at
10UU
y
1400
1200
1OOO
800
60O
4OO
200
n
P*.
*^
=
MI
r
_
=
Li.
. 1
i
\
ir -<-<
- ,
X
/
-
/
K
f
1
1
;
/
/
1
f
\
**'
1
j
.,
L_
_.
_
_
._
_
&
E
C
)A
YS
/
25 50 50 1OO 2OO 3OO 400 500
Chart 36 The volume of outer hair cells and of their nuclei, in cubic micra,
tables 67 and 69.
Volume of outer hair cells.
._. Volume of nuclei of outer hair cells.
six days. After nine days the volume increases always from base
to apex.
Comparing the weighted vo'ume in each turn according to
age, we find that the rate of increase in volume is smallest in
turn I (1.3 to 1.2) and largest in turn IV (3.9 to 4.6) (table 70).
In table 72 are given the weighted values for the diameters
of the nuclei of the inner and outer hair cells in each turn. They
GROWTH OF THE INNER EAR OF ALBINO RAT
99
increase and then decrease during the first twelve days. The rate of
decrease is largest in turn I, and smallest in turn IV, as the ratios
at the bottom of each column show. That the diameters at
2000
1800
1600
1400
1200
1000
800
600
400
200
A
.
.
i.
.
',
'
.
.
,
!
*
' 1
J
'
.
,
I
\
.
.
i
s
1
>,
1
*s
-^
\
1
N
I
's.
^
.
X
1
4
s
\
j
'
""^
X 1
1
^
~*
\
,
i>
,.'
01
f
/
\
--
^
-
f^
B
H.
m
.
=:
~t ~
OH
*
~<
^
*
.
j
t
A
^GE DAVs
i i i i i
25
50
5O 1OO 2OO 30O 40O 5OO
Chart 37 The volume of outer hair cells, according to the turns of the
cochlea, table 67.
the later ages have about the same value in each turn, or are a
little larger in the upper than in the lower turn, is to be seen
in table 73.
TABLE 68
Mean diameters of the nuclei of the inner and outer hair cells in M
DIAMETERS NUCLEI OF THE
DIAMETERS NUCLEI OF THE
INNER HAIR CELLS
OUTER HAIR CELLS
WEIGHT
AGE
BODY
wght
Turns of the cochlea ju
Turns of the cochlea M
ED
AVERAGE
I
II
ill
IV
Average
I
II
ill
IV
Average
days
gms.
1
5
8.6
8.3
7.8
7.8
8.1
7.7
8.1
7.4
7.6
7.7
7.8
3
8
8.6
8.5
8.2
7.8
8.3
8.3
8.4
8.J
7.5
8.1
8.2
6
11
8.5
8.6
8.3
8.0
8.3
8.0
8.0
8.1
7.9
8.0
8.1
c
10
8.7
8.5
8.2
8.7
8.5
76
7.9
8.4
8.2
8.0
8.1
12
13
7.6
7.7
7.5
7.9
7.7
5.8
6.5
6.8
7.4
6.6
6.9
15
13
7.5
7.5
7.7
7.9
7.6
6 1
6.6
6.8
7.0
6.6
6.9
20
29
7.0
7.3
7.6
7.8
7.4
6.0
6.4
6.9
7.3
6.6
6.8
Av. 11
14
8.0
8.0
7.9
8.0
8.0
7.0
7.3
7.5
7.6
7.3
7.5
25
36
7.3
7 2
7.2
7.1
7.2
6.0
6.3
6.3
6.5
6.3
6.5
50
59
7.0
75
7.3
7.3
7.3
6.0
6.2
6.3
6.7
6.3
6.6
100
112
6.7
7.0
7.1
7 1
7.0
5.8
6.0
6.0
6.0
5.9
6.2
150
183
6.6
6.8
7.0
7.3
6.9
6.0
6.0
6.2
6.1
6.0
6.2
257
137
6.6
6.9
7.0
7.7
7.0
5.9 16.0
6.2
6.4
6.1
6.3
366
181
7.6
7.4
7.3
7.2
7.4
5.9
6.0
6.1
6.0
6.0
6.4
546
255
6.5
6.5
6.5
7.1
6.6
5.8
6.0
6.1
6.4
6.1
62
Av. 213! 138
6.9
7.0
71
7.3
7.1
5.9
6.1
6.2
6.3
6.1
6.3
Ratios 1- 12 days
1:1. 0,|
1 :0.9|| 1 :0.9
1- 20 "
:0.9
:0.9 :0.9
1-546 "
:0.8
:O.S 0.8
20-546 "
:0.9 |
:0.9 :0.9
TABLE 69
Average volumes of the nuclei of the inner and outer hair cells (charts 33, 34 and 36)
AGE
BODY WEIGHT
VOLUME OF NUCLEUS HAIR CELLS
Inner Outer
WEIGHTED
VOLUMES
INNER AND OUTER
HAIR CELLS
days
gms.
M'
M
M 3
1
5
278
239
248
3
8
299
278
289
6
11
299
268
278
9
10
322
268
278
12
13
239
151
172
15
13
230
151
172
20
29
212
151
165
25
36
195
131
144
50
59
204
131
151
100
112
180
108
125
150
183
172
113
125
257
137
180
119
131
366
181
212
113
137
546
255
151
119
125
Ratios 1- 12 days
1- 20 "
1-546 "
20-546 "
1 :0.9
:0.8
:0.5
:0.7
:0.6
:0.6
:0.5
:0.8
:0.7
:0.7
:0.5
:0.8
100
GROWTH OF THE INNER EAR OF ALBINO RAT
101
The growth of the inner hair cell. The volume of the inner
hair cell table 67 (chart 34) increases with age up to twenty
TABLE 70
Weighted volumes of the inner and outer hair cells according to the turns of the
cochlea
AGE
BODY WEIGHT
TURNS OF THE COCHLEA M*
I
II
ill
IV
days
gms.
1
5
795
715
587
427
3
8
940
1038
952
657
6
11
1129
1088
1177
905
9
10
1048
1415
1593
1574
12
13
1002
1361
1679
1664
15
13
1011
1288
1672
1701
20
29
1052
1352
1698
2017
25
36
1011
1346
1632
1775
50
59
978
1306
1640
1911
100
112
966
1367
'1569
1807
150
183
965
1237
1773
1917
257
137
991
1304
1601
1939
366
181
992
1320
1693
1957
546
255
940
1374
1681
1944
Ratios 1- 12 days
1 : 1.3 1
1.9
1 :2.9
1 :3 9
1- 20 "
:1.3
1.9
:2.9
:4.7
1-546 "
: 1.2
1.9
:2.9
:4.6
20-546 "
:0.9
1.0
:1.0
:1.0
TABLE 71 Condensed
Ratios of the weighted volumes of the inner -and outer hair cells according to the turns
of the cochlea
BATI08 BETWEEN TURNS
AGE
BODY WEIGHT
I-II
i-ni
I-IV
days
0ms.
1
5
1 :0.9
1 :0.7
1 :0.5
8
11
:1.2
:1.3
:1.2
18
21
:1.3
: 1.6
: 1.8
213
138
:1.4
:1.7
:1.9
days; to nine days rapidly, then slowly. After twenty days it
decreases slowly, as do the weighted volumes of the inner and
outer hair cells, and with fluctuations, is nearly the same after
102
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
100 days. The three condensed age groups show that from
1 to 11 days it has increased 80 per cent, while from 11 to 213
days it has gained less than 2 per cent.
TABLE 72
Weighted diameters of the nuclei of the inner and outer hair cells according to the
turns of the cochlea
AGE
BODY WEIGHT
TURNS OF THE COCHLEA M
I
II
ill
IV
days
gms.
1
5
7.9
8.2
7.5
7.7
3
8
8.4
8.4
8.1
7.6
6
11
8.1
8.2
8.2
7.9
9
10
7.9
8.1
8.4
8.3
12
13
6.3
6.8
7.0
7.5
15
13
6.5
6.8
7.0
7.2
20
29
6.3
6.6
7.1
7.4
25
36
6.3
6.5
6.5
6.7
50
59
6.3
6.5
6.6
6.9
100
112
6.0
6.3
6.3
6.3
150
183
6.2
6.2
6.4
6.4
257
137
6.1
6.2
6.4
6.7
366
181
6.3
6.4
6.4
6.3
546
255
6.0
6.1
6.2
6.6
Ratios 1- 12 days
1 :0.8
1 :0.8
1 :0.9 1
1.0
1- 20 "
:0.8
:0.8
:0.9
1.0
1-546 "
:0.8
:0.7
:0.8
0.9
20-546 "
: 1.0
:0.9
:0.9
0.9
TABLE 73. Condensed
Ratios of the weighted diameters of the nuclei of the inner and outer hair cells
according to the turns of the cochlea
RATIOS BETWEEN TURNS
AVERAGE AGE
AVERAGE BODY
WEIGHT
I-II
i-m
I-IV
days
gms.
1
5
1 :1.0
1 0.9
1 1.0
8
11
:1.0
1.0
1.0
18
21
:1.0
1.1
1.1
213
138
:1.0
1.0
1.1
From nine days on the volume of the inner hair cell increases
in passing from the base to the apex. During the earlier stages
GROWTH OF THE INNER EAR OF ALBINO RAT
103
there are some fluctuations (table 67, chart 35). In the condensed table 74 the general relations are shown. The growth
of the nuclei of the inner hair cells in diameter is given in table 68.
As we see, the diameters increase from birth to nine days,
then decrease slowly but steadily. In the three average age
groups, however, the values decrease continuously with age.
In table 69 are given the values for the volumes of the nuclei
of the inner hair cell (chart 34).
TABLE 74 Condensed
Ratios of the volume of the inner hair cells according to the turns of the cochlea
RATIOS BETWEEN TURNS
AVERAGE AGE
AVERAGE BODY
WEIGHT
I-II
i-in
I-IV
days
grams
1
5
1 0.8
1 0.7
1 0.5
11
14
1.1
1.2
1.2
213
138
1.1
1.3
1.5
TABLE 75 Condensed
Ratios of the diameters of the nuclei of the inner hair cells according to the turns of
the cochlea
RATIOS BETWEEN TDRN8
AVERAGE AGE
AVERAGE BODY
WEIGHT
I-II
I-II I
I-IV
days
grams
1
5
1 1.0
1 :0.9
1 0.9
11
14
1.0
:1.0
1.0
213
138
1.0
:1.0
1.1
The ratios of the diameters of the nuclei of the inner hair
cells decrease at the earlier ages in each turn from the base to
the apex. After nine days they are nearly the same in all the
turns (tables 68 and 75), though their absolute values decrease
in all the turns after nine days.
The growth of the outer hair cells. In general, the changes in
the volume of the outer hair cells are like those in the inner
hair cells. Therefore, the volume increases strikingly up to nine
days of age, then gradually to twenty days. The main dif
104
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
ference is that the volume in the outer hair cells does not diminish
so much after twenty-five days, but holds nearly the same value
(table 67, chart 36). In condensed age groups, therefore, we see
a large increase in the size of the cells with age.
To determine the growth of the outer hair cells in each turn
of the cochlea, table 67 is used (chart 37). From twenty days on
the values increase from the basal to the apical turn. Before
twenty days the relations are irregular or reversed. In table
76 this relation is clearly brought out.
Comparing the changes of the volume of the outer hair cells
in three age groups (table 67), we find that the average volume
increases throughout each turn with age, except in turn I, where
TABLE 76 Condensed
Ratios of the volumes of the outer hair cells according to the turns of the cochlea
RATIOS BETWEEN TURNS
AVERAGE AGE
AVERAGE BODY
WEIGHT
I-II
i-in
I-IV
days
grams
1
5
1 1.0
1 0.8
1 0.6
11
14
1.3
1.6
1.5
213
138
1.5
1.9
2.2
that at eleven days is largest. In the inner hair cells, however,
values at eleven days are largest in both turn I and II.
For the nuclei of the outer hair cells, the diameters are given
in table 68). Here the d ! ameters tend to increase from one to
nine days. At twelve days they decrease strikingly, and after
that very slowly. In table 69 are given the values for the volumes
of the nuclei of the outer hair cells.
In table 68 are given also the measurements for the nuclei
of the outer hair cells according to the turn of the cochlea.
At nine days and after, the diameters become larger in passing
from base to apex, while in the earlier stages this relation is
irregular or reversed. The decrease of the measurements in,
each turn with age is clearly shown in the three age groups.
GROWTH OF THE INNER EAR OF ALBINO RAT
105
In table 77 are given the average ratios of turn I to the three
other turns.
The comparison of the growth of the inner and outer hair
cells. As already stated, the growth of the inner and outer hair
.cells in volume proceeds in about the same way till they reach
their full size at twenty days. After that we note a difference
between them. While the outer hair cells maintain a nearly
constant volume, the volume of the inner hair cells diminishes
TABLE 77 Condensed
Ratios of the diameters of the nuclei of the outer hair cells according to the turns of
the cochlea
RATIOS BETWEEN TURNS
AVERAGE AGE
AVERAGE BODY
WEIGHT
I-II
I-II I
I-IV
days
grams
1
5
1 1.1
1 1.0
1 1.0
11
14
1.0
1.1
1.1
213
138
1.0
1.1
1.1
TABLE 78 Condensed
Comparison of the volumes of ike inner and the outer hair cells
AVERAGE VOLUMES HAIR CELLS
AVERAGE AGE
AVERAGE BODY
RATIOS OF INNER
WEIGHT
TO OUTER
Inner
Outer
days
grams
M
A
1
5
925
533
1 0.6
11
14
1665
1169
0.7
213
138
1693
1385
0.8
somewhat with age. When we consider the volume according
to the three age groups, it increases in both groups throughout
life (table 78). There are, however, large differences in the rate
of increase. The inner hair cell increases its volume at 11 days
by 80 per cent and between 11 and 213 days by less than 2 per cent.
For the outer hair cells the increase by 11 days is 120 per cent
and from 11 to 213 days, 19 per cent. At the same time the inner
are always larger than the outer hair cells, as the ratios in table
78 show.
106
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
The diameters of the nuclei in both the inner and outer hair
cells diminish in value after nine days of age. This decrease
is larger in the outer than in the inner cells. In table 79 are
given the values for the diameters of the nuclei in both inner and
outer hah* cells. In the last column are the ratios between them.
Thus, while the volumes of the outer hair cells, as compared
with the inner hair cells, become relatively larger with age (table
78), the diameters of their nuclei become relatively smaller
(table 79).
TABLE 79 Condensed
Comparison of the diameters of the nuclei of the inner and outer hair cells
AVERAGE DIAMETERS OF THE
AVERAGE
NUCLEI OF THE HAIR CELLS
RATIOS OF THE AVERAGE
DIAMETERS OF THE NUCLEI OP
AVERAGE AGE
BODY
WEIGHT
Inner
Outer
CELLS
days
grams
M
M
1
5
8.1
7.7
1 1.0
11
14
8.0
7.3
0.9
213
138
7.1
6.1
0.9
Comparison of the growth of the inner and outer hair cells
according to sex. A careful and elaborate comparison has been
made to determine whether there are differences in the growth
of the hair cells according to sex.
In table 80 are given the average values for the volumes of
the cell bodies and their respective nuclei. No significant differences according to sex were found.
Comparison of the growth of the inner and outer hair cells
according to side. The same treatment of the data was followed
as in the determination for the influence of sex. In table 81 are
given the average values for the volumes of the inner and outer
hair cells and their respective nuclei. Again no significant
differences according to side were found.
On the nucleus-plasma ratios of the inner and outer hair cells.
For the inner and outer hair cells here measured the weighted
volumes of the cell bodies and of their nuclei are entered in the
condensed table 82, and the ratios of the volume of the nucleus
GROWTH OF THE INNER EAR OF ALBINO RAT
107
to that of the cytoplasm (=cell volume less nucleus volume)
are given in the last column. This ratio increases with age,
as table 82 shows. While the ratio is 1.5 in the youngest and
smallest group, it is 9.9 in the largest. This means that as a
group these cells are continually growing in volume. This result
may be analysed for the two groups of cells involved.
TABLE 80
Average volumes of inner and outer hair cells and of their respective nuclei
in n 3 according to sex
INNER HAIR CELLS
OUTER HAIH CELLS
WEIGHTED AVERAGE
Att
BODY
NO. OF
BEX
Average volume
Average volume
VOLUME
BATS
Cell
Nucleus
Cell
Nucleus
CELLS
NUCLEI
da j/5
grams
3
7
1
0*
1213
310
815
268
915
278
8
1
9
1319
310
888
322
996
319
6
11
2
tf
1426
289
955
278
1073
281
10
2
9
1372
310
979
268
1077
278
9
10
2
cT
1701
310
1351
258
1439
271
9
2
9
1895
345
1203
278
1376
295
12
14
2
c? 1
1830
258
1344
157
1466
182
12
2
9
1886
221
1221
151
1387
168
100
146
1
cT
1687
180
1342
113
1428
129
103
1
9
1779
212
1319
108
1434
184
150
189
1
rf 1
1679
165
1382
119
1456
131
154
1
9
1639
212
1611
119
1618
142
365
205
1
tf
1739
258
1389
119
1477
154
170
1
9
1659
221
1486
113
1529
140
Volume greater in male 3
2
3
4
5
3
Volume greater in female 4
4
4
2
2
4
Equal
1
1
.
The nucleus-plasma ratio of the inner and outer hair cells
considered separately. This is shown for the inner hair cells
in table 83. The ratios are also progressive, but somewhat
larger for the earlier age groups and smaller for the oldest, than
in the previous instance.
The ratios for the outer hair cells are also progressive, and
the range is greater than for the inner hair cells as table 84 shows.
Here the ratio is 1.2 for the youngest group and 10.6 for the
108
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
oldest. This indicates that at one day and eleven days the
relative volume is less in the outer than in the inner hair cells,
but at the later age the outer hairs cells grow more.
TABLE 81
Volumes of the inner and outer hair cells and of their respective nuclei according
to side in ft 3
AGE
BODY
WEIGHT
NO. OF
BATS
SIDE
INNER HAIR CELLS
OXJTER HAIR CELLS
WEIGHTED AVERAGE
VOLUME
Average volume
Average volume
Cell
Nucleus
Cell
Nucleus
CELLS
NUCLEI
1
5
2
R.
895
299
555
248
640
261
L.
955
268
511
230
622
239
3
7
1
R.
1213
310
815
268
915
278
L.
1395
299
920
299
1039
299
6
11
2
R.
1381
322
1010
278
1103
289
L.
1416
289
923
258
1046
268
9
9
2
R.
1782
310
1177
268
1328
278
L.
1815
333
1378
268
1487
284
12
12
1
R.
1887
212
1310
151
1454
166
L.
1885
221
1132
151
1320
168
15
13
1
R.
1895
230
1522
144
1615
165
L.
1848
239
1419
151
1526
172
20
29
2
R.
1914
212
1365
144
1502
161
L.
1862
221
1472
165
1570
179
25
36
2
R.
1758
204
1307
131
1420
149
L.
1792
195
1351
131
1461
147
50
59
2
R.
1741
204
1443
125
1518
145
L.
1687
204
1305
137
1401
154
100
102
2
R.
1675
187
1355
113
1440
131
123
2
L.
1658
172
1339
113
1419
128
150
189
1
R.
1565
172
1420
113
1456
128
L.
1679
165
1382
119
1456
131
257
137
2
R.
1685
187
1377
125
1454
140
L.
1607
180
1416
119
1464
134
367
175
2
R.
1634
195
1436
113
1486
134
365
188
2
L.
1848
230
1374
113
1493
142
546
255
2
R.
1831
157
1474
119
1563
128
L.
1559
151
1353
119
1405
127
Volume greater on right side 7
8
9
3
7
6
Volumfe greater on left side 7
5
5
5
6
8
Equal
1
6
1
GROWTH OF THE INNER EAR OF ALBINO RAT
109
This seems to be important and to illustrate the fact that in
the papilla spiralis the growth of the elements lying nearer the
axis occurs earlier than that of the elements nearer the periphery.
TABLE 82 Condensed
Nucleus-plasma ratios of the inner and outer hair cells M*
AVERAGE
AGE
AVERAGE
BODY
WEIGHT
AVERAGE VOLUME OF
INNER AND OUTER HAIR CELLS
VOLUME OK
CYTOPLASM
NUCLEUSFLA8MA RATIOS
Cell
Nucleus
days
1
11
213
grams
5
14
138
631
1293
1462
248
226
134
383
1067
1328
1 : 1.5
:4.7:9.9
TABLE 83 Condensed
Nucleus-plasma ratios of the inner hair cells /**
AVERAGE
AGE
AVERAGE
BODY
WEIGHT
AVERAGE VOLUME OF 1XXER
HAIR CELLS
VOLUME
or
CYTOPLASM
NUCLEUSPLASMA RATIOS
Cell
Nucleus
days
1
11
213
0ms.
5
14
138
925
1665
1693
278
268
187
647
1397
1506
1 2.3
5.2
8.1
TABLE 84 Condensed
Nude us- plasma ratios of the outer hair cells
AVERAGE
AGE
AVERAGE
BODY
WEIGHT
AVERAGE VOLUME OF OUTER
HAIR CELLS
VOLUME or
CYTOPLASM
NUCLEUSPLASMA
RATIOS
Cell
Nucleus
days
1
11
213
grams
5
14
138
533
1169
1385
239
204
119
294
965
1266
1 1.2
4.7
10.6
17. Deiters' cells. The Deiters' cells are most delicate elements. In the literature, so far as I know, there are no exact
observations touching the growth of these cells in the papilla
spiralis, except a few data for their length. They have an
110 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
irregular form and consist of three parts, the phalangeal process,
cell body, and foot. The phalangeal process is thin, somewhat
crooked in the adult though it runs straight at an earlier stage.
As the boundary between this process and the cell body, we
take a line running through the supporting cup ('Stutzkelch' of
Held) parallel to the plane of the basilar membrane (fig. 10).
The cell body in its upper part is wide, including here a round
nucleus. It then becomes thin and passes over to the foot.
Thus it is almost impossible to get the true volume of the cells.
Therefore, we have determined the volume of the cell body
only, excluding that of the phalangeal process.
We think of the cell body as a cylinder having an average
diameter, which is calculated from four diameters measured at
four levels. The first level is just below the upper boundary
of the cell body, the second in the widest part, the third below at
about the middle of the cell body, and the last is at the narrowest
part near the foot. .
The height of the cylinder is the length of the cell body within
the limits just noted. Thus the volume obtained approximates
the value for the natural size of the cell body without the process.
In table 85 (chart 38) are given the values for the volumes of
the Deiters' cells thus computed and the diameters and volumes
of the nuclei according to age. As there are in the radial section
three rows of cells, the values given are, of course, the average
of these. At the bottom of the last column appear the ratios at
1 to 12, 1 to 20, 1 to 546, and 12 to 546 days. As we see, the
volume of the cell body increases throughout life, slowly during
the first nine days, but from twelve to twenty days very rapidly,
and then less rapidly to old age.
While the ratio from one to twelve days is 1:5.4, that from
1 to 546 days is 1:29.1, or more than five times as large.
When we consider the volumes of the cells in each turn of
the cochlea, we see that it is smallest in turn I and largest in
turn IV, though there are some exceptions before nine days
of age. Table 86 shows these relations.
The diameters of the nuclei of the cells grow, after some
fluctuations in the values at earlier stages, very slowly to old
GROWTH OF THE INNER EAR OF ALBINO RAT 111
age, as indicated in table 85 and chart 38. The ratios at the
bottom of the corresponding column show these relations. The
values for the volumes of the nuclei of the cells are given in the
last column. Here, also, the diameters in the upper turns tend to
be larger than in the basal turn. In table 87 are given the ratios
of the diameters of turn I to the three other turns. We see in
all the turns about the same ratios, 1:1.0.
In the literature we find but two observations on the diameters
of the nuclei of the Dieters' cells. Kolmer ('07) reports hi the
pig 5 [i, and von Ebner ( '02) gives in man 7 (x for the diameter
of the round nucleus of the cells.
In the rat, therefore, the diameter is larger than in these
two forms, but no significance can be attached to this difference
until correction has been made for the several techniques employed. This I am unable at present to do.
On the nucleus-plasma ratio in Deiters 1 cells. In the condensed
table 88 are given the volumes of the cell bodies and of their
nuclei together with the respective nucleus-plasma ratios. This
shows that the ratio is progressive with age. While the ratio
is at birth only 0.05, that in the oldest group is 28.3. The absolute
increase is not great at earlier stages, but by eighteen days it
is marked
The rapid change in the ratio is very interesting. Before
eight days of age the cells are still immature. Some time after
eight days they develop rapidly, seeming to play some important
part in the special functions of the cochlea.
On the length of Deiters' cells. To measure the length of
Deiters' cells we divide them into two parts, the upper and the
lower, by the boundary line between the cell body and the phalangeal process. The sum of these two lengths makes the total
length of the cells.
In table 89 are given the values for the total length and for
each part separately (chart 39). As in the volume of the cells,
we see an astonishing change in the development of the length.
The length of the cells increases through life, at earlier stages a
little, but at twelve days it becomes nearly twice as long as at nine
days. The ratios at the bottom of the last column show the
course of growth.
TABLE 85
The volume of Deiters' cells and the mean diameters and volumes of their respective
nuclei (chart 38)
VOLUME OF THE DEITERS* CELLS
1
NUCLEI
VOLUMES
BODY
fit
Diameters
AGE
WEIGHT
Average
I
II
III
IV
Average
I
II
III
IV
diam
Average
volume
eters
volumes
M
M
days
grams
1
5
278
232
237
256
251
7.6
7.5
7.5
8.1
7.7
239
3
8
290
309
349
352
325
7.0
7.0
6.9
7.0
7.0
180
6
11
425
395
495
364
420
7.0
6.5
6.7
6.6
6.7
165
9
10
635
461
554 423
518
6.9
7.0
7.1
7.1
7.0
180
12
13
1122
1369 1395
1569
1364
6.5
7.0
6.9
7.1
6.9
180
15
13
1466
2187 2659
3127
2359
7.0
7.2
7.2
7.3
7.2
195
20
29
3576
427115740
6171
4939
7.6
7.8
7.9
7.9
7.8
248
25
50
36
59
4088 4467 5470
4839 5970 6258
5757
6816
4695
5971
7.3
7.3
7.2
7.5
7.3
7.5
7.4
7.4
7.3
7.4
212
212
100
112
5011
6083
7137 6607
6210
6.9
7.6
7.5
7.4
7.3
212
150
183
5755 6291 7657
6750
6613
7.5
7.6
7.5
7.1
7.4
212
257
137
5776 6540 8841
8544
7425
7.4
7.8
7.9
8.0
7.8
248
366
181
6163
6908
7701
7895
7167
7.4
7.7
7.9
7.9
7.7
248
546
255
6092 6919 8028
8152
7298
7.4
7.9
8.0
7.7
7.7
248
Ratios 1 12 days
1 5.4
1 0.9
1 20 "
19.7
1.0
1546 "
29.1
1.0
12546 "
5.4
!
1.1
TABLE 86 Condensed
Ratios of volumes of the Deiter's cells according to turns of the cochlea
RATIOS BETWEEN TURNS
AVERAGE AGE
AVERAGE BODY
WEIGHT
I-II
i-m
I-IV
days
grams
1
5
1 :0.8
1 :0.9
1 :0.9
8
11
:1.0
: 1.1
: 1.1
18
21
: 1.3
: 1.7
: 1.8
213
138
: 1.1
: 1.4
: 1.3
TABLE 87 Condensed
Ratios of the diameters of the nuclei of Deilers' cells according to turns of the cochlea
RATIOS BETWEEN TURNS
AVERAGE AGE
AVERAGE BODY
WEIGHT
I-II
I-III
I-IV
days
grams
1
5
1 1.0
1 1.0
1 : 1.1
8
11
1.0
1.0
: 1.0
18
21
1.0
1.0
:1.0
213
138
1.0
1.1
:1.0
112
GROWTH OF THE INNER EAR OF ALBINO RAT
113
90OO
8OOO
7OOO
6000
5000
4000
3OOO
2OOO
1OOO
AGE
o
25
50
50 1OO 2OO 300 4OO 5OO
Chart 38 Showing the volume of Deiters' cells and their nuclei, on the
average and according to the turns of the cochlea, table 85.
Average volume of Deiters' cells.
._. Volume of the cells in about the middle of the basal turn.
Volume of the cells in about the beginning of the middle turn.
Volume of the cells in about the middle of the middle turn.
-..-..-.. Volume of the cells in about the beginning of the apical turn.
-...-.. Average volume of nuclei of Deiters' cells, X 10.
114
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
Comparing the length of the cells according to the turn of
the cochlea, we find that after twelve days the length increases
from the base to the apex, in turn III very rapidly, in turn IV
gradually (table 90). At earlier stages the relations are irregular.
TABLE 88 Condensed
Nucleus-plasma ratios of the Deiters' cells
AVERAGE VOLUMES
VOLUME OF
NUCLEUS
AVERAGE AGE
AVERAGE BODY
CYTOPLASM
PLASMA RATIOS
WEIGHT
Cell
Nucleus
.M
M
M
days
grams
1
5
251
239
12
1 : 0.05
8
11
657
172
485
: 2.8
18
21
3649
221
3428
: 15.5
213
138
6483
221
6262
:28.3
TABLE 89
Length of cell body and of processus phalangeus of Deiters' cells p (chart 39)
LENGTH OF THE CELL BODY
LENGTH OF THE PROCESSUS
PHALANGEUS
TOTAL
BODY
LENGTH
AGE
WEIGHT
Turns of cochlea
Turns of cochlea
OF THE
CELLS
I
II
III
IV
Average
I
II
ill
IV
Average
days
gms
1
5
8
8
8
9
8
20
19
20
15
19
27
3
8
8
9
9
10
9
16
17
18
18
17
26
6
11
9
9
11
10
10
19
22
23
22
22
32
9
10
18
12
13
11
14
18
21
26
24
22
36
12
13
31
35
40
43
37
18
22
29
25
24
61
15
13
34
37
40
43
39
21
25
32
31
27
66
20
29
39
41
49
49
45
19
23
30
34
27
72
25
36
42
43
51
51
47
17
21
30
32
25
72
50
59
41
45
53
53
48
16
22
30
34
26
74
100
112
43
45
54
53
49
17
25
29
31
26
75
150
183
45
46
53
52
49
17
22
32
34
26
75
257
137
43
46
56
58
51
18
24
28
31
25
76
366
181
43
48
55
55
50
17
23
29
32
25
75
546
255
46
49
56
56
52
16
23
30
33
26
78
Ratios 1 12 days
1 :4.6
1 :1.3
1 :2.3
1 20 "
:5.6
: 1.4
:2.7
1546 "
:6.5
:1.4
:2.9
12546 '"
: 1.4
:1.1
: 1.3
GROWTH OF THE INNER EAR OF ALBINO RAT
115
When we consider the length of the cell body, it is remarkable
that the increase takes place so rapidly. While at 1 day it
measures only 8 (x and at nine days only 14 ji, it increases very
suddenly at twelve days of age, and after that slowly but continuously (table 89).
TABLE 90
Total length of Deiters' cells according to turns of the cochlea (chart 39)
AGB
BOOT WEIGHT
TURNS OF THE COCHLEA
I
II
III
IV
days
grams
1
5
28
27
28
24
3
8
24
26
27
28
6
11
28
31
34
32
9
10
36
33
39
35
12
13
49
57
69
68
15
13
55
62
72
74
20
29
58
64
79
S3
25
36
59
64
81
83
50
59
57
67
83
87
100
112
60
70
83
84
150
183 '
62
68
85
86
257
137
61
70
84
89
366
181
60
71
84
87
546
255
62
72
86
89
80
M
60
40
20
n
^
<
="
>
"^
/
/
~
~
/
,'
>
P
;
*-.
'*
,/
"'
ft
G
E
DA
*/c
Tb
25 50 50 10O 200 30O 400
Chart 39 The length of Deiters' cells, tables 89 and 90.
500
Total length of the cells.
Length of the cell bodies.
Length of processus phalangeus.
116
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
In the ratios at the bottom of table 89 this is shown very
evidently and in each turn this relation is to be seen.
For the length of the phalangeal process the story is quite
different. It increases from birth to twelve days a little; at
fifteen days it reaches full size, and then holds its value (table 89) .
After three days the length is smallest in turn I and largest in
turn IV. This relation lasts to old age.
Comparing the growth of the length of the cell body and
phalangeal process, there is a large difference between them.
While the length in the phalangeal process is at birth over twice
that of the cell body, at 546 days it is only half that of the cell
TABLE 91
Total length of Deiters' cells in fj, (Retzius)
AGE
RABBIT
CAT
Basal
Middle
Apical
Average
Basal
Middle
Apical
Average
turn
New-born
48
70
60
59
45
65
48
53
2
45
66
54
55
1
3
45
60
7
80
90
75
82
49
69
63
60
10
98
100
114
104
11
75
90
45
70
14
84
105
112
100
30
54
75
70
66
body. Thus the increase of the total length of Deiters' cells
is due chiefly to the increase in the length of the cell body.
Retzius ('84) gives the length of Deiters' cells in the rabbit
and cat as in table 91.
Table 91 shows that in both the rabbit and the cat the length
at all ages is greater, and especially at the earlier stage is twice
as great, as in the rat. In the rabbit there is a rapid increase
in length between seven and ten days. For the cat the values
are smaller, nearer those of the rat, and show less change between
birth and thirty days.
18. Summary and discussion. Using the foregoing data on
the form and measurements of the elements of the cochlear
duct, I desire here to summarize the results and to discuss the
consequent changes in the form of the organ of Corti (table 92).
GROWTH OF THE INNER EAR OF ALBINO RAT 117
We have already noted that at birth the greater epithelial
ridge constitutes the main part of the tympanic wall, and the
lesser epithelial ridge, from which arises later the most important
organ, is represented by a small and undeveloped prominence.
With age this greater ridge disappears gradually and is transformed into a furrow lined with low epithelial cells, the sulcus
spiralis internus (Waldeyer). These changes appear first at the
base and then pass gradually to the upper turns. In the lesser
ridge also there are important developmental changes. At first
the hair cells and pillar cells grow, and just before the special
function appears, striking changes are seen in Deiters' and
Hensen's cells. These increase, especially in their length, very
rapidly.
Thus the papilla spiralis, which hitherto had its highest
point at the summit of the arch of Corti, shows a remarkable
change of form, as the outer part of the papilla increases its
height, so that finally Hensen's cells mark the highest point
in the papilla. The surface then ceases to be parallel to the
basilar membrane, and slopes inward, making with the basilar
membrane an acute angle opening outward. At the same time
the papilla spiralis appears to be shifted inward i.e., towards
the axis.
Kolliker has described how the cells, from which the pillars or
rods of Corti arise, at first stand nearly parallel, but later separate
at their base. He thought that this "von einem Langenwachstum (?) der Zellen selbst oder ihrer Grundlage, der Membrana basilaris, abhiingen kann. "
Hensen ('63) first studied this interesting problem in the ox
and found it to depend on a peculiar process. He regarded the
inward migration as taking place chiefly in the inner pillar cell.
The outer pillar cell in the upper turn moves somewhat outward ;
in the base, however, inward. Moreover, the outer pillar cell
increases its length during the development of the papilla much
more than the inner does. Thus the summit of the arch of Corti
and therefore the papilla spiralis shifts inward on the basilar
membrane.
118
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
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GROWTH OF THE INNER EAR OF ALBINO RAT
119
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120
Bottcher ( '69. 72) disagreed with Hensen, though he has confirmed, as did Middendorp ('67), the striking inward spreading
of the base of the inner pillar cell.
Gottstein] ( 72) held that the inner pillar cell does not move
inward, but that the increase in the length of the labium tympanicum may explain the peculiar approach of the habenula
perforata to the arch of Corti.
Retzius ('84) agreed in general with Hensen 's assertion that
in the course of development the surface of the sense organ
comes to lie under the basal surface of the membrana tectoria.
He thought that this change of position is brought about "weniger in dem Verhalten der Pfeilerzellen, sondern vor allem in
dem starken Wachstum der Deitersschen Zellen und der von
aussen andriickenden Hensenschen Stiitzzellen, ' and that,
further, "vielleicht die Membrana tectoria selbst durch eigenes
Wachstum und durch Vergrosserung des Limbus mit seinem
Vorspriingen" contributes to this.
Held ('09) agrees with Hensen on the whole.
Prentiss ('13, p. 450) denies the wandering of the spiral organ
as follows: ''There is no necessity for, and my preparations
afford no proof of, an inward shifting of the spiral organ and
a consequent displacement of the membrana tectoria "
Hardesty ('15, pp. 60 and 61) discussed the relative position
of the spiral organ with reference to the basal surface of the
tectorial membrane and says " the developed spiral organ acquires
its position well under the basal surface of the tectorial membrane
almost entirely by being carried axisward during the completion
of the membrane." "In the apical turn, where these changes
are greatest, the hair cells of the organ may be carried axisward
a distance nearly half the width of the membrane. The upgrowth
of the outer supporting cells also forces axisward the apical
ends of the elements of the spiral organ and in this way contributes a small part to the shift in the relative position of the
hair cells. A slight increase in width of the vestibular lip of
the spiral limbus may contribute a still smaller part by extending
the membrane outward."
GROWTH OF THE INNER EAR OF ALBINO RAT 121
I obtained from the measurements given in the tables the
following results concerning the position of the papilla spiralis
under the basal surface of the tectorial membrane.
As already stated, since the habenula perforata may be considered after birth as a punctum fixum (Hensen), it is found
that the inner pillar cell shifts inward at its inner basal corner
during the earlier stage of life. At six days of age it almost
always reaches the habenula perforata in the basal turn, though
not yet in the apical. At nine days there is no distance between
the- habenula perforata and the inner corner of the inner pillar
cell.
Gottstein's assumption (no measurements) that the labium
tympanicum grows outward and approaches to the arch of Corti
is not applicable to the rat, as shown by my tables.
The outer pillar cell also moves outward in all the turns
through life, but only slightly after nine days. This result does
not agree with that of Hensen ('63), who found in the ox the
outer pillar cell to move inward a little at the base, not at all
in the middle turn and outward at the apex. Bottcher 's outward
movement of the outer pillar cell at the hamulus in the cat is
90 y. and much larger than in the rat.
Contrary to Hensen, Retzius ('84) also finds in the rabbit an
outward movement of the base of the outer pillar cell throughout
all the turns. On the other hand, during the earlier stages of
development, the top of the arch of Corti moves outward from
the labium vestibulare through the outward pressure of the
greater epithelial ridge. At this stage the main part of the
membrana tectoria does not yet reach to the sense cells, though
the part produced from the lesser epithelial ridge spans the
spiral organ and connects with the outer part of the papilla.
After nine days of age the condition of the organ is quite
different. The most remarkable anatomical changes from the
earlier condition are the rapid increase in the length of the outer
pillar cells, in the height of the pillar cells above the basilar
membrane, in the height of the papilla spiralis at the third series
of the outer hair cells, in the height of Deiters' cells, and in the
height of Hensen 's supporting cells. Also the tunnel of Corti
appears.
122 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
The greater epithelial ridge has already disappeared in large
part and been replaced by a furrow. Pressure displacement
of tissue in the direction of the least resistance is common in
organogenesis. Thus the inner pillar cell is subject to pressure
by the rapid growth of the outward lying and greater part of
the papilla spiralis and moves in the direction of the least resistance, therefore inward; the head most and the base not at all.
As shown in table 44, the rapid decrease in the radial distance
between the labium vestibulare and the head of the inner pillar
cell is very evident. The arch of Corti changes its form, now
inclining inward, instead of outward as heretofore. The lamina
reticularis runs not parallel to the basilar membrane, but ascends
outward. The tunnel of Corti also changes more or less its form.
Nuel 's space now appears possibly as a result of this displacement
of the papilla spiralis. Thus we see a change in the position
of the sense organ with reference to the membrana tectoria.
With the inward shifting of the papilla, the hair cells come
under the basal surface of the membrana tectoria. It is probable
that the increase of the relative length of the membrane also
takes part in this, since the increase in the breadth of the inner
zone of the membrana tectoria from one to twelve days is as
1:3.4 (table 4), while the increase in the breadth of the basilar
membrane is as 1:0.5 during the same interval (table 7).
Prentiss' ('13) statement that an inward shifting of the papilla
spiralis and a consequent displacement of the membrana tectoria
does not take place (in the pig) is not applicable to the rat.
In the rat the labium vestibulare and the inner edge of the
head of the inner pillar cell are also two definite points in the
same sense, and using them we see an inward shifting of the
organ of Corti. I imagine that his observation may have misled
him, since the tectorial membrane arises in his preparations
from both greater and lesser epithelial ridges, and from the
earlier stages covers with its outer part the papilla spiralis.
Thus the shifting of the organ inward does not necessitate a
change in the position of the papilla with reference to the membrane. In his study of the tectorial membrane in the same
animal (pig) , Hardesty ( ' 13) describes a large displacement of the
papilla spiralis inward.
GROWTH OF THE INNER EAR OF ALBINO RAT 123
According to him, the shifting of the organ consists of, 1, the
moving axisward of the organ itself, and this constitutes the
main shift; 2, the upgrowth of the outer supporting cells, and
this contributes a small part to the shift, and, 3, a slight increase
of the vestibular lip of the spiral limbus which may contribute
a still smaller part. The relation in the rat, however, is different.
The moving inward of the papilla itself is not seen in the rat.
In the earlier stages the inner basal corner of the inner pillar
cell alone shifts inward and reaches the habenula perforata.
On the other hand, the outer pillar cell moves outward and
the head of the inner pillar cell also, at earlier stages, towards
the cells of Hensen. Therefore, during the earlier stages the
arch of Corti moves rather outward, owing to the pressure of
the growth of the greater epithelial ridge. Since the habenula
perforata is to be regarded as a fixed point, the inward displacement of the head of the arch of Corti and of the papilla spiralis
is not due to the active shifting inward of the organ itself, as
Hardesty ('15) thinks, but to the disappearance of the greater
ridge and the passive pressure exerted by the upgrowth of the
outer pillar cells and Deiters' and Hensen 's cells. The vestibular
lip of the spiral lamina and the tectorial membrane itself both
increase in their length a little, and these increases play some
part in the change of the position of the papilla spiralis with
reference to the basal surface of the tectorial membrane.
The membrana basilaris is not concerned with the moving
inward of the organ. It increases its length with age in all the
turns, but we do not find the change in the position of the feet
of the pillar cells on the membrane in such a sense that the
feet move inward on it.
Thus the shifting of the papilla spiralis inward in the rat
during the development takes place rather in the manner described by Retzius.
Hardesty ('15) states that in the apical turn of the cochlea the
organ may be moved axisward a distance equal to about half
the maximum width of the greater epithelial ridge, the maximum
width of the ridge representing approximately the width of the
outspanning zone of the membrane produced upon it.
124
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
No other author reports such a high degree of the inward
shifting of the organ. I have not studied the pig, but in the
rat I get the average distance between the labium vestibulare
and the inner edge of the head of the inner pillar cell as follows
(table 93).
TABLE 93
Average distance between the labium vestibulare and the inner edge of the inner
pillar cell in n (albino rat)
AGE
BODY WEIGHT
TURNS OF COCHLEA
I
II
III
IV
Average
days
grams
(1) 5
(2) 154
Difference betw
1 and 2
9
102
een age groups
94
63
31
124
100
24
1,54
134
20
165
148
17
23
Therefore, in the rat the organ moves inward on the average
of 23 [A; that is, in the ratio of 1:0.16 of the maximum distance
between these two points. It may be noted that the difference
in this table is not the same in the several turns, but diminishes
from base to apex a relation which is the reverse of that reported
by Hardesty ('15) in the pig. I have no explanation for these
differences except their possible dependence on the different
animals used.
C. On the growth of the largest nerve cells in the ganglion spirale
Observations. For the present studies the fourteen age groups
used in the previous observations on the growth of the tympanic
wall of the cochlear duct were employed. In order to see the
relation between the growth of the papilla spiralis and the cells
of the ganglion spirale, both studies were made on the same
sections. In addition, however, I made cross-sections of the
cochlea (i.e., at right angles to the axis) in several age groups
to follow the growth and the changes in the form of the nerve
cells as they appear in this plane. The data for the animals
thus used are given in table 94.
For the measurement of the nerve cells a Zeiss system was used
with a micrometer eyepiece, having each division equal to 2jx.
Since we have in the radial vertical section of the cochlea of the
rat at least four turns, there are four cell groups available in
each section (fig. 3). The ten largest cells in each ganglion
were measured, and thus a total of forty cells in a section were
taken for the measurement of the nucleus and the cell.
We used, as stated, four cochleas in each age group, so that
160 cells were measured for each age. Also in the cross-sections
the four nearly corresponding turns were used for the measurements, selecting the ten largest cells in each turn.
TABLE 04
Data on rals used for cross-sections of the cochlea ganglion spirale
AGE
BOOT WEIGHT
BODY LENGTH
BEX
8IDE
HEARING
days
grams
15
20
84
(?
L.
Prompt response
20
27
93
d"
L.
25
39
114
P
L.
100
95
152
<?
R.
150
169
192
9
L.
371
220
206
c?
L.
In the measurement of the cell bodies the two maximum
diameters at right angles to each other were determined, and
also the two corresponding diameters for the nuclei.
Here it is to be noted that the expressions turn I, II, III,
and IV are used in the same sense as in the earlier chapters.
In table 95 (chart 40) are given the values for the average
diameters of the cell bodies and their nuclei in the ganglion
spirale in the radial vertical section according to fourteen age
groups. Under 'cell body, diameter,' the first column gives the
long, the second the short, and the third the computed diameter;
i.e., the square root of their products. These last values approximate the mean diameters of the nerve cells. At the foot
of the third column are given the ratios from 1 to 20, 1 to 546,
and 20 to 546 days. The values for the diameters of the nurlei
are similarly given and also the ratios.
126
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
As the tables and charts show, the diameters of the cell bodies
and also of their nuclei are largest at twenty days of age. After
that age they diminish, gradually. While the ratio for one to
twenty days is 1:1.7 in the cell bodies and 1:1.3 in the nuclei,
that for 1 to 546 days is 1:1.6 and 1:1.2, respectively.
TABLE 95
Diameters of the cell bodies and their nuclei in the ganglion spirale (radial-vertica I
section) (chart 40)
Diameters in M
Cell body
Nucleus
AGE
BOOT
BODY
WEIGHT
LENGTH
Long
Short
Computed
Long
Short
Computed
days
grams
mm.
1
5
48
11.0
10.0
10.5
8.2
7.6
7.9
3
8
56
12.0
11.1
11.5
8.2
7.8
8.0
6
11
63
13.6
12.3
12.9
8.8
8.1
8.4
9
10
58
14.3
12.8
13.6
8.9
8.2
8.5
12
13
70
14.6
13.1
13.8
8.7
8.2
8.5
15
13
75
15.7
14.1
14.9
9.1
8.4
8.7
20
29
95
19.0
17.3
18.1
10.3
10.0
10.2
25
36
104
18.5
16.9
17.7
10.2
9.9
10.1
50
59
125
18.5
16.6
17.5
10.3
9.7
10.0
100
112
159
18.1
15.7
16.9
9.8
9.2
9.5
150
183
190
18.2
15.3
16.7
9.6
8.8
9.2
257
137
175
18.5
15.3
16.8
9.9
9.4
9.6
366
181
191
18.6
15.3
16.9
9.8
9.0
9.4
546
255
213
18.6
15.3
16.9
9.7
9.0
9.4
Ratios
120 days
1:1.7
1:1.3
1546 "
:1.6
:1.2
20546 "
:0.9
:0.9
In table 96 (chart 41) are a series of computed diameters
of the cell bodies and of their nuclei according to the turns of the
cochlea. At the bottom of each column are given the ratios
from 1 to 20, 1 to 546, and 20 to 546 days. Determining the
ratios for each column, it appears that in general the diameters
of the cell bodies and their nuclei are largest at twenty days
throughout all the turns. This increase is very considerable from
fifteen to twenty days. Then they decrease very slowly till
546 days.
GROWTH OF THE INNER EAR OF ALBINO RAT
127
Table 97 enables us to compare the ratios in the diameters of
the cell bodies and their nuclei in turns I, II, III, and IV in the
condensed age groups. In both the cell bodies and their nuclei
the ratios become slightly larger in passing from the basal toward
the apical turn, except in the one day group, which it reversed.
On the comparison of the diameters of the nerve cell bodies
and their nuclei in the ganglion spirale according to sex. For
this comparison seven age groups were used. In each age group
we have sometimes one, sometimes two cochleas of the same sex.
*u
M
15
10
5
r\
/
'*
**
-4
>
1
'<
1
j
f *
*
/
^
?
""
-i
_
_
___
J]
_
-.
. _,
_
..
_
_.
v*
'
*
G
E
D
A
/Si
25 50 5Q .Qo 2(X) 30Q 40Q
5OO
Chart 40 Showing the computed diameter of the largest cell bodies and their
nuclei from the ganglion spirale, table 95.
----- Diameters of the cell bodies.
---------- Diameters of the nuclei.
In the latter case the average value is recorded. In table 98
are given the values for these diameters, and it is plain that
there is no significant difference in these values according to sex.
On the comparison of the diameters of the nerve cell bodies
and their nuclei in the ganglion spirale according to side. For
this purpose fourteen age groups were employed. In most
cases two cochleas from the same side were used in each age group.
In these cases the average value is recorded. Table 99 shows the
values for the diameters of the cell bodies and their nuclei according to side, but reveals no evident difference in this character.
128
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
On the morphological changes in the ganglion cells during
growth. As my sections could not be stained with thionine, my
observations on the Nissl bodies are incomplete, yet the slides
stained with Heidenhain's iron haematoxylin and van Gieson's
stain, as well as by haematoxylin and eosin, were helpful here.
TABLE 96
Computed diameters of the cell bodies and their nuclei in the ganglion spirale
according to the turns of the cochlea (chart 41 )
AGE
days
BODY
WEIGHT
gms
TURNS OF THE COCHLEA
Computed diameters M
I
II
in
IV
Cell
body
Nucleus
Cell
body
Nucleus
Cell
body
Nucleus
Cell
body
Nucleus
1
5
11.0
8.0
10.8
8.2
10.4
8.0
9.6
7.4
3
8
11.5
7.9
11.5
7.9
11.7
8.0
11.3
8.1
6
11
12.9
8.4
12.6
8.2
13.0
8.5
13.3
8.6
9
10
13.4
8.4
13.4
8.5
13.6
8.6
13.7
8.6
12
13
13.6
8.1
13.5
8.1
13.8
8.6
14.7
9.0
15
13
14.8
8.6
15.0
8.6
14.6
8.6
15.0
9.2
20
29
17.6
10.0
17.6
9.9
18.1
10.2
19.0
10.4
25
36
16.9
9.9
17.6
10.0
17.6
10.1
18.4
10.3
50
59
17.2
9.7
17.2
9.7
17.6
10.0
17.9
10.1
100
112
16.9
9.6
16.9
9.4
16.3
9.3
16.9
9.6
150
183
16.9
9.3
16.3
9.0
16.6
9.1
17.0
9.1
257
137
16.7
9.6
16.7
9.4
16.9
9.7
17.0
9.7
366
181
16.7
9.3
16.4
9.2
16.7
9.1
17.7
9.7
546 255
Ratios 1 20 day*
1546 "
20546 "
15.8
1:1 .6
9.2
1:1.3
16.3
1:1.6
9.4
1:12
16.9
1:1.7
9.4
1:1.3
17.4
1:2 .0
9.5
1:14
1 5
1 2
1 5
: 1 2
1 7
1 2
1 8
: 1 3
:1.0
:0.9
:0.r
: 1.0
:0.?'
:0.9
:O.S
: 0.9
TABLE 07 Condensed
Ratios of the diameters of the cells and nuclei of the ganglion spirale
AVERAGE
AGE
AVERAGE
BODY
WEIGHT
RATIOS BETWEEN TURNS
I-II
l-lll
I-IV
Cell body
Nucleus
Cell body
Nucleus
Cell body
Nucleus
days
1
8
18
13
grams
5
11
21
138
1 :0.98
:0.99
: 1.01
:0.99
1: 1.25
: 1.00
: 1.00
:0 99
1:0-95
: 1.01
: 1.01
: i.OI
1 : 1 . 00
: 1.02
: 1.01
: 1 . 00
1 : . 87
: 1.03
1.04
: 1.04
1 :0.93
: 1.05
: 1 . 05
: 1.02
GROWTH OF THE INNER EAR OF ALBINO RAT
129
19
M
18
17
16
15
14
13
12
10
9
Si;
DAYSi
i i
25
50
, oo 2OO 3OO 4OO
Chart 41 'The computed diameter of the largest cell bodies and of their
nuclei from the ganglion spirale, according to the turns of the cochlea, table 96.
Upper graphs: diameters of the coll bodies. Lower graphs: diameters of the
nuclei of the cells.
130
Figure 13 illustrates semidiagrammatically the nerve cells
in the spiral ganglion of the albino rat at 1 day and at 20 and 366
days.
The body of the ganglion cells at birth is small and has the
characteristic fetal form. The cytoplasm is homogeneous and
scanty and the Nissl bodies are not yet seen. The nucleus forms
TABLE 98
Comparison according to sex of the diameters of the cell bodies and the nuclei in
the ganglion spirale
AGE
BODY WEIGHT
NO. OF RAT8
SEX
COMPUTED DIAMETERS M
Cell
Nucleus
days
grams
3
7
1
&
11.4
8.0
8
1
9
11.4
8.0
6
11
2
tf
13.1
8.5
10
2
9
12.8
8.4
9
10
2
c?
13.6
8.5
9
2
9
13.5
8.6
12
14
2
c? 1
13.7
8.5
12
2 .
9
13.9
8.4
100
146
. 1
<?
17.2
9.6
103
1
9
16.9
9.4
150
189
1
d 1
16.5
9.1
154
1
9
17.1
9.1
365
205
1
d 1
16.3
9.0
170
1
9
16.7
9.1
Average male
14.5
8.7
Average f e male
14.6
8.7
Male larger than female
3
3
Female larger than male
3
2
Male and female equal
1
2
the greater part of the cell. The chroma tin is not yet well
differentiated, and the so-called 'Kernfaden' are not visible.
The sharply marked nucleolus is in most cases in the central
position, but sometimes located peripherally.
The cytoplasm matures rapidly. At six days the Nissl bodies
appear, though they are of course, less abundant and smaller
than in the later stages. The nucleus develops also and the
chromatin is well differentiated. Thus the development in both
the cell body and the nucleus proceeds rapidly in the earlier
stage.
20 Days
13
366 Days
Fig. 13 Showing semi-diagrammatically the size and the morphological
changes in the ganglion cells in the ganglion spirale of the albino rat at the age of
1, 20 and 366 days. All cell figures have been uniformly magnified 1000 diameters.
GROWTH OF THE INNER EAR OF ALBINO RAT
131
At twenty days the cell body reaches its maximum size. The
Nissl bodies are large and abundant. The nucleus also attains
TABLE 99
Comparison according to side of the cell bodies and their nuclei in the ganglion
spirale
AGE
SIDE
COMPUTED I.I \ M K r Ml- ft
Cell
Nucleus
days
grams
1
5
2
R.
10.6
8.0
L.
10.4
7.8
3
7
1
R.
11.4
8.0
L.
11.5
8.0
6
11
2
R.
13.0
8.5
L.
12.9
8.4
9
9
2
R.
13.4
8.5
L.
13.7
8.6
12
12
1
R.
13.9
8.4
L.
14.0
8.4
15
13
1
R.
14.7
8.6
L.
14.8
8.5
20
29
2
R.
18.0
10 1
L.
18.5
10.2
25
36
2
R.
17.6
10.1
L.
17.7
10 1
50
59
2
R.
17.5
9.9
L.
17.5
9.8
100
102
2
R.
16.8
9.5
123
L.
17.0
9.5
150
189
1
R.
16.4
9.2
L.
16.5
9.1
257
137
2
R.
17.1
9.7
L.
16.6
9.5
367
175
2
R.
17.3
9.7
365
188
L.
16.5
9.1
546
255
2
R.
16.9
9.3
L.
16.9
9.9
Average right side
Average left side
Right larger than left
Left larger than right
Right and left equal
15.3
ir>.:j
4
8
2
9.1
'.M)
7
2
5
its maximum size at this age, though the rate of increase is slower
than that for the cell body. With this increase of size the histological structure becomes that of the adult rat. Then, as the
132
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
age advances, the size of both the cell body and of the nucleus
slowly diminishes, while within the cytoplasm the differentiation
of the Nissl bodies progresses. This relation is seen in the figure
of the cell at 366 days, which shows that the absolute volume
of the cell body and also of the nucleus is smaller than at twenty
days.
From twenty to 366 days, gradual and progressive changes
in all histological structures can be seen, though there are no
sudden changes.
TABLE 100
Diameters of the cell bodies and their nuclei in the ganglion spirale in cross sections
of the cochlea (chart 4%)
DIAMETERS IN M
AGE
BODY
Cell body
Nucleus
Long
Short
Computed
Long
Short
Computed
days
grams
15
20
15.7
14.3
15.0
9.3
8.4
8.8
20
27
18.3
16.6
17.4
10.3
10.0
10.1
25
39
18.0
16.6
17.3
10.1
9.8
9.9
100
95
17.6
16.2
16.9 '
9.9
9.5
9.7
150
169
17.4
16.0
16.7
9.8
9.1
9.4
371
220
16.5
15.8
16.2
9.5
8.6
9.0
Ratios 15 25 days
1 1.1
1 1.1
15371 "
1.1
1.0
25371 "
1.0
0.9
The question here arose whether this change in volume was
in any way related to a shift in the long axis of the cell at the
later ages. To answer this difficult question it was deemed
desirable to compare the form of the ganglion cells obtained in
the cross-section with that found in the radial section of the
cochlea. In table 100 (chart 42) are given the values for the
diameters of the cell bodies and their nuclei in the ganglion
spirale in the cross-section. Below are given the respective
ratios from 15 to 25, 15 to 371, and 25 to 371 days. Both cell
body and nucleus increase in size up to twenty days and then
diminish very slowly, as the age advances. These are similar
to the relations found in the radial sections.
GROWTH OF THE INNER EAR OF ALBINO RAT
133
Looking at the diameters of the cell bodies and their nuclei
in each turn (table 101), we do not find in the later age groups a
regular increase in passing from the base toward the apex, as
in the cells on the radial section. The differences are generally
TABLE 101
Diameter of the cell bodies and their nucki in the ganglion spirale according to the
turns of the cochlea (cross section)
TURNS OV THE COCHLEA
AGE
BODT
WEIGHT
I
II
ill
IV
Computed diameters ft
Cell
body
Nucleus
Cell
body
Nucleus
Cell
body
Nucleus
Cell
body
Nucleus
days
15
grams
20
15.0
8.7
14.7
8.8
14.9
8.9
14.9
9
20
27
16.7
9.7
17.2
10.0
17.5
10.1
18.1
10 6
25
100
39
95
16.9
17.2
10.0
10.0
17.2
16.9
9.9
9.6
17.6
16.7
9.8
9.6
17.3
16.8
10.0
9 6
150
169
17.0
9.9
16.6
9.3
16.6
9.4
16.4
9 1
371
Ratio 15
220
371 days
16.2
1:1.1
9.6
1:1.1
16.2
1:1.1
9.1
1:1.0
16.0
1:1.1
8.7
1:1.0
16.3
1:1.1
9.0
1:1.0
20
15
10
AGE DAYS
O
25
50
Chart 42 The average diameter of the largest cell bodies and of their
nuclei of the nerve cells from the ganglion spirale, after 15 davs (cross-section)
table 100.
Cell bodies. -.-.-.-.-. Nuclei.
134 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
far smaller than on the radial section. This result seems to have
some connection with the position of the long axis of the ganglion
cells in relation to the axis of the cochlea.
Comparing the diameters of the cell bodies and their nuclei
in nearly corresponding places in the radial and cross-section,
the long diameters of the cells are in each age group almost
always larger in the radial than on the cross-section. Therefore
the cells are somewhat ovoid. The short diameters, however,
are at the same age sometimes longer, sometimes shorter on the
radial than on the cross-sect on. This is probably due to the
fact that in the upper turns the cells stand with their long diameter
more nearly parallel to the axis of the modiolus, and therefore,
on passing from the upper to the lower turn, the long axes of
the cells become more inclined to the modiolus.
In order to show that the cell form is ovoid, I reconstructed
the cells at 15, 100, and 365 days of age by the usual method,
and obtained models which agreed in form with that determined
by the microscope.
It appears, therefore, that while there is some difference in
the diameters of these cells according to the plane of the section,
neverthless, the change in volume after twenty days is similar
in both cases, and so this change does not depend on the plane in
which the sections were made.
On the nucleus-plasma relations of the cells in the ganglion
spirale. The computed diameters of the cell bodies and their
nuclei, measured on radial sections, are given in table 102 and
the nucleus-plasma ratios have been entered in the last column.
The ratio is at one day only 1:1.3 and increases rapidly and
regularly till twenty days; after that period there are slight fluctuations. Generally speaking, the ratios increase with the advancing age of the rat, but after twenty days only very slightly.
Thus we see that the nucleus-plasma relation nearly reaches an
equilibrium at twenty days, though the cells mature slowly
even after that time.
When we consider this relation according to the turns of the
cochlea, we find that this ratio increases in all the turns regularly
and definitely till twenty days, after which there are some
GROWTH OF THE INNER EAR OF ALBINO RAT
fluctuations (table 103). Thus we see here also the same relation
as before.
TABLE 102
Nucleus-plasma ratios of cells in the ganglion spirale (radial-vertical section)
AGE
BODY
WEIOHT
BOOT
LENGTH
COMPUTED DIAMETERS M
Cell body
Nucleus
N ucleus-plasma
ratios
days
grams
mm.
1
5
48
10.5
7.9
1 : 1.3
3
8
56
11.5
8.0
:2.0
6
11
63
12.9
8.4
:2.6
9
10
58
13.6
8.5
:3.1
12
13
60
13.8
8.5
:3.3
15
13
75
14.9
8.7
:4.0
20
29
95
18.1
10.2
:4.6
25
36
104
17.7
10.1
:4.4
50
59
125
17.5
10.0
:4.4
100
112
159
16.9
9.5
:4.6
150
183
190
16.7
9.2
:5.0
257
137
175
16.8
9.6
:4.4
366
181
191
16.9
9.4
:4.8
546
255
213
16.9
9.4
:4.8
TABLE 103
Nucleus-plasma ratios of cells in the ganglion spirale according to the turns of the
cochlea. Based on table 96
AQB
BODY WEIOHT
TURNS Or THE COCHLEA
I
ii
in
IV
days
grama
1
5
1 :1.6
1 :1.5
1 :1.2
1 : 1.2
3
8
:2.1
:2.1
:2.1
:1.7
6
11
:2.6
:2.6
:2.6
:2.7
9
10
:3.1
:2.9
:3.0
:3.0
12
13
:3.7
:3.6
:3.1
:3.4
15
13
:4.1
:4.3
:3.9
:3.2
20
29
:4.5
:4.6
:4.6
:5.1
25
36
:4.0
:4.5
:4.3
:4.7
50
59
:4.6
:4.6
:4.5
:4.6
100
112
:4.5
:4.8
:4.4
:4.5
150
183
:5.0
:4.9
:5.1
:5.5
257
137
:4.3
:4.6
:4.3
:4.4
366
181
:4.8
:4.7
:5.2
:5.1
546
255
:5.1
:4.2
:4.8
:5.1
136
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
In the nucleus-plasma ratio of the cells on the cross-section,
as shown in table 104, the increase with age is very regular.
As the diameters of the cell bodies and their nuclei decrease
slowly after twenty days, this increase of the ratio means that
the nuclei are diminishing relatively more rapidly than the
cytoplasm.
Comparing these ratios from the radial and cross sections,
we find that they agree (table 105) .
TABLE 104
Nucleus-plasma ratios of the cells in the ganglion spirale (cross-sections)
COMPUTED DIAMETERS M
BODY LENGTH
AGE
BODY WEIGHT
Cell body
Nucleus
Nucleus-plasma
ratios
days
grams
mm.
15
20
84
15.0
8.8
1 4.0
20
27
93
17.4
10.1
4.1
25
39
114
17.3
9.9
4.3
100
95
152
16.9
9.7
4.5
150
169
192
16.7
9.4
4.6
371
220
206
16.2
9.0
4.8
TABLE 105
The nucleus-plasma ratios according to the plane of the section at two age periods
albino rat
AGE
NUCLEUS-PLASMA RATIO
ON THE RADIAL SECTION
NUCLEUS-PLASMA RATIO
ON THE CROSS SECTION
AGE
days
15
1 :4.0
1 :4.0
days
15
366
1 :4.8
1 :4.8
371
Discussion. According to the foregoing data, the maximum
size of the cells in the ganglion spirale, at twenty days, is in
cross-sections about 18.7 x 16.9 y. for the cell body and 10.3 x
10.0 [L for the nucleus. Both the long and short diameter of
the cell body thus obtained is therefore a little less than that
obtained in the radial section, while the diameters for the nucleus are the same.
In the literature we have not found any data for the Norway
rat, but there are a few observations on the size of these cells
in other mammals by Kolliker ('67) and von Ebner ('02).
GROWTH OF THE INNER EAR OF ALBINO RAT
137
Schwalbe ('87) and Alagna ('09) find these ganglion cells 25
to 30 JJL in diameter in the guniea-pig and cat.
Alexander ('99) has also reported measurements on a series
of mammals, but as the size of such cells is greatly influenced
by the method of preparation, and as our averages are based
on the largest cells while those of other authors have been obtained in a different manner, it seems best not to report the other
values in the literature, as they are sure to be misleading.
TABLE 106
Showing the changes with age in the diameters of the cells and the nticlei of the
sjriral ganglion afnd the lamina pyrmidalis of the cerebral
cortex, respectively
AGE '
CELL BODY IN
THE OANQL.
SPIRALS COMPUTED DIAM. M
CELL BODY IN
THE LAMINA
PYRAMID COMPUTED DIAM.
NUCLEUS IN
GANOL. SI-IK.
COMP. DIAM.
NUCLEUS IN
THE LAMINA
PYRAM. COMP.
DIAM.
AGE
days
days
1
10.5
11.4
7.9
9.4
1
20
18.1
18.7
10.2
15.7
20
546
16.9
17.0
9.4
13.8
730
Ratio be
ratio
tween 1 and
1 : 1.7
1 :1.6
1 :1.3
1 :1.3
of Ito
20 days
20
days
Ratio be
ratio
tween 1 and
1 : 1.6
1 : 1.5
1 :1.2
1 :1.2
of Ito
546 days
730
days
Considering the course of growth in these cells, we find it to
be similar in both the spiral ganglion and the lamina pyramidalis
of the cerebral cortex (rat) as reported by Sugita ('18). In the
former the cells attain at twenty days of age, the time of weaning, their maximum size, and then diminish slowly with advancing
age. The cells of the lamina pyramidalis also reach their full
size at twenty days, and then diminish in the same way. Therefore, the course of the growth of both of these groups of nerve
cells coincides. However, I do not know of other instances
of the phenomenon. When tabulated, the relations here noted
appear as in table 106.
The difference between them is only in the absolute values
of the diameters of the cell bodies and especially of the nuclei,
138
the nuclei in the cells of the lamina pyramidalis being decidedly
larger than in those of the spiral ganglion. The ratios of increase are, however, similar.
When we consider the increasing ratios of the diameters of
the ganglion cells, we see a close similarity in the maximum values
between the cells in the spiral and gasserian ganglion (Nittono,
'20). Nevertheless while in the former the ratios from 1 to 20
and 1 to 366 days are in the cell bodies 1:1.7 and 1 : 1.6, respectively, in the latter the ratios for the corresponding intervals are
1: 1.43 and 1: 1.69, respectively (Nittono, '20, p. 235). In the
nucleus also similar relations are to be seen in both ganglia.
As these ratios show, there is in the gasserian ganglion a definite
increase in the diameters of cells and nuclei after 20 days of age;
the time when the maximum is reached by the cells of the spiral
ganglion. Thus the former continue to grow after growth in
the latter has ceased. These results suggest that the neurons in
the more specialized ganglia, like the spiral ganglion, may mature
earlier than do those in the less specialized.
On the correlation between the growth of the hair cells of the papilla
spiralis and of the nerve cells of the ganglion spirale. When we
compare the growth changes in the hair cells with those in the
ganglion cells, we find that the course of the development is
similar. Both classes increase in volume from one to twenty
days of age, then tend to diminish slowly the hair cells more
slowly than the ganglion cells. In the ratios of increase, however,
there are marked differences. Thus in table 67 (bottom of last
column) the volume ratios from 1 to 20 and 20 to 546 days are
1 : 2.4 and 1 : 0.9, respectively in the hair cells, and in the ganglion
cells, table 108, the ratios of the volumes in the fourth column
work out for the corresponding ages as 1: 5.1 and 1: 0.8, respectively. In the case of the nuclei the growth changes are
somewhat different. In the hair cells the nucleus grows in
diameter more rapidly, and therefore reaches at nine days its
maximum value and then diminishes at succeeding ages.
I have sought to determine whether there was any correlation
in growth between either the entire cylindrical surface or the area
of the cross-section of the hair cells, on the one hand and the volume
139
of the cells of the ganglion spirale on the other. The reason for
making this comparison was the fact that Levi ('08), Busacca
('16), and Donaldson and Nagasaka ('18) have noted in the cells
of the spinal ganglia of several mammals that the postnatal
growth in volume was correlated with the increase in the area of
the body surface, and recently Nittono ('20) has found in the
rat a similar relation between the growth of the cells of thegasserian
ganglion and the area of the skin of the head. On examining
this problem, it is evident that the correlations thus far reported
TABLE 107
Comparison of ratios between the volumes of the cells of the ganglion spirale. nn<l ///
ratios of the area of the cylijidrical surface of the hair
cells of the organ of Corti on the maximum values
AOE
BOOT
WEIGHT
VOLUME OP 1 III
ClANllI.ION CELL,
/'
RATIOS ON
THE
MAXIMUM
VALUE
AKEA OF
CYLINDRICAL
SURFACE OF THE
HAIR CF.LLH- M *
1ATIO8 ON THE
MAXIMUM
VALUE
days
gms.
I
5
606
3105
1 :5.12
395
723
1
1.83
3
8
796
:3.90
463
1.56
6
11
1124
:2.76
582
1.24
9
10
1317
:2.36
648
1.12
12
13
1376
:2.26
681
1.03
15
13
1732
:1.79
729
0.99
20
29
3105
: 1.00
723
1.00
25
36
2903
: 1.07
691
1.05
50
59
2806
:1.11
697
1.04
100
112
2527
: 1.23
678
1.07
150
183
2439
:1.28
691
1.05
257
137
2483
: 1.25
689
1.05
366
181
2527
: 1.23
683
1.06
546
255
2527
: 1.23
699
1.03
apply to the postnatal growth period, and that we must consider
that the functional relations of the skin are well established,
even at the earliest age. The data with which we have worked in
the case of the cochlea are presented in several tables (107 to
110).
In tables 107 and 108 are given the volumes of the cells of the
ganglion spirale and the areas of the cylindrical surface of the
hair cells. In table 107 the ratios are computed by dividing the
maximum value by the values at each age, and in table 108 by
dividing the values at each age by the initial value.
TABLE 108
Comparison of the ratios of the volume of the cells of the ganglion spirals with the
ratios of the area of the cylindrical surface of the hair cells of the organ of
Corti on the initial values
AGE
BOOT
WEIGHT
VOLUME OF THE
GANGLION
CELLS M *
RATIOS ON THE
INITIAL
VALUE
AREA OF THE
CYLINDRICAL
SURFACE OF THI
HAIR CELLS M
RATIOS ON
, THE INITIAL
\ VALUE
days
grams
1
5
606 : 606
1
1.00
395
395
1
1.00
3
8
: 796
1.31
463
1.17
6
11
: 1124
1.85
582
1.47
9
10
: 1317
2.17
648
1.64
12
13
: 1376
2.27
681
1.72
15
13
: 1732
2.86
729
1.85
20
29
:3105
5.12
723
1.83
25
36
:2903
4.79
691
1.75
50
59
:2806
4.63
697
1.76
100
112
:2527
4.17
678
1.72
150
183
:2439
4.02
691
1.75
257
137
:2483
4.10
689
1.74
366
181
:2527
4.17
683
1.73
546
255
:2527
4.17
699
1.77
TABLE 109
Area of the cross-section of the inner and outer hair cells
WEIGHTED
DIAMETER OF
AVERAGE
DIAMETER OF
WEIGHTED
AGE
BODY
ONE INNER
DIAMETER OF
INNER AND
AREAS OF CROSS
WEIGHT
HAIR CELL
THREE OUTER
OUTER HAIR
SECTION OF
M
HAIR CELLS
CELLS
HAIR CELLS
M
M
M 2
days
grams
1
5
6.6
6.0
6.2
30
3
8
8.0
7.4
7.6
45
6
11
8.1
7.6
7.7
48
9
10
8.8
8.5
8.6
5S
12
13
8.5
8.3
8.4
55
15
13
8.4
7.7
7.9
50
20
29
8.8
8.2
8.4
55
25
36
8.8
8.1
8.3
55
50
59
8.8
8.2
8.4
55
100
112
8.6
8.1
8.2
53
150
183
8.5
8.3
8.4
55
257
137
8.5
8.3
8.4
55
366
181
8.8
8.4
8.5
58
546
255
8.6
8.2 | 8.3
55
GROWTH OF THE INNER EAR OF ALBINO RAT
141
I have calculated the cylindrical surface of the hair cells
according to the formula for the lateral surface of a cylinder;
therefore, this area equals 2 v r a (r = radius, a = height of the
cylinder) . As the hair cells are more or less pointed at their lower
end, the surface obtained by this formula has nearly the value of
the total surface of the hair cells less that for the upper end disk.
As has been already shown, both classes of cells grow rapidly
from birth to twenty days, and after that both tend to decrease
slightly in volume. It is evident that during the growing period,
TABLE 110
Comparison of the ratios of the volume of the cells of the ganglion spirale with the
ratios of the areas of the cross-section of the inner and outer hair cells
of the organ of Corti
AOE
days
BODY
WEIGHT
gms
VOLUME OF THE
GANGLION
CELLS M '
RATIOS ON THE
INITIAL
VALUE
AREA Or THE
CROSS-SECTION
OF THE HAIR
CELLS
RATIOS ON THE
INITIAL
VALUE
1
5
606
606
1
1.00
30 :30
1
1.00
3
8
796
1.31
:45
1.50
6
11
1124
1.85
:48
1.60
9
10
1317
2.17
:58
1 . 9
12
13
1376
2.27
:55
1.83
15
13
1732
2.86
:50
1.67
20
29
3105
5.12
:55
1.83
25
36
2903
4.79
:55
l s:;
50
59
2806
4.63
:53
1.77
100
112
2527
4.17
:53
1.77
150
183
2439
4.02
:55
1.83
257
137
2483
4.10
:55
1.83
366
181
2527
4.17
:58
1.93
546
255
2527
4.17
:55
1.83
from one day to the end of the record, the volumes of the ganglion
cells increase more rapidly than do the cylindrical areas of the
hair cells (table 108). If we seek a numerical expression of these
relations, it seems best to start not with the values at birth, but
with those at nine days of age when the cochlea is just beginning
to function, and to extend the comparison only up to twenty days
when both groups of cells have reached their maximum size.
Thus at nine days (table 108) the volume of the ganglion cells
is 1317 [A 3 , while at twenty days it is 3105 [A 3 , or as 1: 2.3, while
the area of the cylindrical surfaces of the hair cells at the respective
142 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
ages is 648 [x 3 and 723 [i 3 , or as 1 : 1.1, thus showing a rapid growth
of the ganglion cell bodies accompanied by but slight enlargement
of the hair cells.
It is evident from these ratios that the ganglion cells are
increasing in volume more rapidly than the hair cells in area.
It is possible that the nervus cochlearis innervates the other
cells of the cochlea as well, but even if this is taken into consideration the general relations remain the same.
It follows from this that during the period between the earliest
appearance of the functional response (nine days) and the
attainment of the maximum size of the cells, the innervation
of the hair cells is steadily improving, if we may infer such an
improvement from the increase in the volume of the ganglion
cells. After the close of this early growing period the relations
are approximately fixed through the remainder of life. We do
not find, therefore, in the cochlea any relation which corresponds to those found between the spinal ganglion cells or those
of the gasserian ganglion and the associated areas of the skin
during postnatal growth. This seems to indicate that in the
cochlea growth is fixed or limited, while in the body as a whole
it is more or less continuous, and the ganglion cells behave
differently in the two cases.
In table 109 are shown the diameters of the inner and outer
hair cells and their weighted diameters. In the last column
is given the area of the cross-section of the hair cells.
The ratios of these areas on the initial area are shown in table
110 in comparison with the volumes of the ganglion cells on the
initial volume, and indicate that from three days of age the
values for the ganglion cells are increasing more rapidly than
those for the area of the cross-section of the hair cells, and at
twenty days the increase in the case of both elements has reached
a maximum. Here, as in the case of the cylindrical surface,
both elements show like phases of growth, but the increase in
the volumes of the ganglion cells is much greater than the increase
in the cylindrical area or cross-section of the hair cells.
As it may be desirable to use for comparison the measurements on the cells of the ganglion spirale as here reported, the
GROWTH OF THE INNER EAR OF ALBINO RAT
143
constants for the determinations based on 160 cells in each age
group are given in . table 111 for the radial vertical sections
and in table 112 for the cross-sections.
TABLE 111
A nalytical constants* giving the mean, standard deviation and coefficient of variability
unth their respective probable errors for the diameters of the cells and their
nuclei of the ganglion spirale in radial vertical section
AOK
days
FOR TOTAL NUMBER "K CELLS
Cell
Nucleus
Mean
Standard
deviation
Coefficient of
variability
1
Cell
10.2 0.05
0.90 0.03
8.9 0.33
Nucleus
7.8 0.02
0.46 0.01
5.9 0.22
3
Cell
11.3 0.03
0.50 0.02
4.4 0.17
Nucleus
7.9 0.02
0.32 0.01
4.1 0.15
6
Cell
12.6 0.04
0.68 0.03
5.4 0.20
Nucleus
8.4 0.03
0.48 0.02
5.7 0.22
9
Cell
13.1 0.03
0.61 0.02
4.7 0.18
Nucleus
8.5 0.03
0.52 0.02
6.1 0.23
12
Cell
13.4 0.05
0.86 0.03
6.4 0.24
Nucleus
8.4 0.03
0.61 0.02
7.3 0.28
15
Cell
14.6 0.04
0.73 0.03
5.0 0.13
Nucleus
8.7 0.03
0.58 0.02
6.7 0.25
20
Cell
17.8 0.06
1.17 0.04
6.6 0.25
Nucleus
10.0 0.02
0.40 0.02
4.1 0.15
25
Cell
17.3 0.05
0.88 0.03
5.1 0.19
Nucleus
9.9 0.02
0.36 0.01
3.6 0.14
50
Cell
17.2 0.04
0.78 0.03
4.5 0.17
Nucleus
9.7 0.02
0.34 0.01
3.6 0.14
100
Cell
16.5 0.03
0.65 0.02
3.9 0.15
Nucleus
9.4 0.02
0.38 0.01
4.0 0.15
150
Cell
16.4 0.03
0.79 0.02
4.8 0.18
Nucleus
9.1 0.02
0.42 0.02
4.6 0.17
257
Cell
16.6 0.06
1.09 0.04
6.6 0.25
Nucleus
9.5 . 02
0.39 0.01
4.1 0.15
366
Cell
16.7 0.05
1.02 0.01
6.1 0.22
Nucleus
9.3 0.03
0.52 0.02
5.6 0.21
546
Cell
16.7 0.06
1 . 06 . 04
6.4 24
Nucleus
9.3 0.02
0.45 0.02
4.9 is
Conclusion. For the study of the growth of the nerve cells
in the ganglion spirale fourteen age groups were taken and the
data obtained from the 160 largest cells in each age group.
Besides these, six age groups, representing six cochleas, were
examined in cross-sections to determine the form of the ganglion
144
ANATOMICAL AND PHYSIOLOGICAL STUDIES ON
cells and the relation of their long axes to the axis of the cochlea.
Here also the ten largest cells in each of four, nearly corresponding turns, were measured. We obtained the following
results :
1 . As thus prepared, the ganglion cells at birth have a maximum
size of 11 x 10 [i in cell body and 8.2 x 7.6 [x in nucleus. At
twenty days the diameters are the largest, 18.7 x 16.9 [x in cell
body and 10.3 x 10.0 [x in nucleus.
TABLE 112
Analytical constants giving the mean, standard deviation and coefficient of variability with their respective probable errors for the diameters of the cells
and their nuclei of the ganglion spirale, in cross-section
AGE
CeU
Nucleus
FOB TOTAL NUMBER OP CELLS
Mean
Standard
deviation
Coefficient of
variability
days
15
Cell
14.7 0.04
0.40 0.03
2.7 0.21
Nucleus
8.9 0.04
0.34 0.03
3.8 0.29
20
Cell
17.1 0.09
0.83 0.06
4.9 0.37
Nucleus
10.0 0.06
0.58 0.04
5.8 0.44
25
Cell
17.1 0.07
0.63 0.05
3.7 0.28
Nucleus
9.8 0.03
0.30 0.02
3.1 0.23
100
Cell
16.7 0.05
0.44 0.03
2.6 0.20
Nucleus
9.6 0.04
0.36 0.03
3.7 0.25
150
Cell
16.4 0.07
0.69 0.05
4.2 0.32
Nucleus
9 . 4 . 05
. 46 . 03
4.9 0.37
371
Cell
16.0 0.06
0.55 0.04
3.5 0.24
Nucleus
9.1 0.05
0.43 0.03
4.7 0.36
2. The ganglion cells grow relatively rapidly after birth and
reach at twenty days of age their maximum size. After having
passed the maximum at twenty days, they diminish in size
very slowly, but the internal structure matures more and more
with successive age.
3. The nuclei are relatively large at birth but increase more
slowly than the cell bodies do; nevertheless, they follow the
same course of development as the latter. This peculiar course
in the growth of the ganglion cells is similar to that followed
by the cells of the lamina pyramidalis of the cerebral cortex
of the rat as found by Sugita ('18)
GROWTH OF THE INNER EAR OF ALBINO RAT 145
4. Within the cochlea the cell bodies and nuclei increase
their diameters from the base toward the apex, except in the
earlier stages.
5. There are no evident differences in the diameters of the
cell bodies and the nuclei of the ganglion cells either according
to sex or side.
6. Both the cell bodies and the nuclei are immature at birth,
but differentiate rapidly, and even at six days the Nissl bodies
are visible. The differentiation proceeds with advancing age.
7. The ganglion cells are bipolar and oval in shape. The
direction of the long axis of the cells differs according to the
turn of the cochlea and in the upper turn it runs almost parallel
to the axis of the modiolus but inclines more and more to the
horizontal position on passing to the base.
8. The nucleus-plasma ratios of the ganglion cells increase
with age in both the radial and cross-sections.
9. The increase in the volume of the ganglion cells and the
area of the cross-section of the hair cells is approximately similar during the first nine days of life, but after that the ganglion
cells increase relatively very rapidly. These relations are very
different from those found for the spinal ganglion cells by Donaldson and Nagasaka ('18) and for the cells of the gasserian
ganglion by Nittono ('20).
The nervus cochlearis innervates not only the hair cells, but
all the elements of the cochlea, and this may have some influence upon this relation. It is interesting to note that the
rate of increase in the cylindrical surface of the hah* cells is
similar to that in the area of the cross-sections of these same
cells.


==II. Correlation Between the Inception of Hearing and the Growth of the Cochlea==
==II. Correlation Between the Inception of Hearing and the Growth of the Cochlea==

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Wada T. Anatomical and physiological studies on the growth of the inner ear of the albino rat. (1923) Memoirs of the Wistar Institute of Anatomy and Biology, No. 10, Philadelphia. Rat Inner Ear (1923): I. Cochlea growth | II. Inception of hearing and cochlea growth | III. Growth of largest nerve cells in ganglion vestibulare | Final Summary | Literature Cited

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Anatomical and Physiological Studies on the Growth of the Inner Ear of the Albino Rat

Tokujiro Wada

Wistar Institute Of Anatomy And Biology

Contents

Introduction 5

Material 6

Technique 6

I. On the growth of the cochlea

A. On the growth of the radial distance between the two spiral ligaments 13

B. On the growth of the tympanic wall of the ductus cochlearis. . . 16

1. Membrana tectoria 28

2. Membrana basilaris 39

3. The radial distance between the habenula perforata and the inner corner of the inner pillar cell at base 47

4. The radial distance between the habenula perforata and the outer corner of the inner pillar cell (resp., the inner corner of the outer pillar cell) at base 48

5. The radial basal breadth of the outer pillar cell (including the outer pillar) 57

6. The radial distance between the habenula perforata and the outer border of the foot of the outer pillar cell 63

7. The greatest height of the greater epithelial ridge (dem grossen Epithelwulst Bottcher's s. Organon Kollikeri) resp. of the inner supporting cells 63

8. The radial distance between the labium vestibulare and the habenula perforata 68

9. The radial distance between the labium vestibulare and the inner edge of the head of the inner pillar cell 71

10. Vertical distance from the membrana basilaris to the summit of the pillar cells 75

11. The greatest height of the tunnel of Corti 77

12. The height of the papilla spiralis at the third series of the outer hair cells 77

13. The greatest height of Hensen's supporting cells 83

14. The angle subtended b> the extension of the surface of the lamina reticularis with the extended plane of the membrana basilaris 84

15. Lengths of the inner and outer pillar cells 85

16. Inner and outer hair cells 94

17. Deiter's cells 109

18. Summary and discussion 116

C. On the growth of the largest nerve cells in the ganglion spirale . 124

observations 124

Discussion 136

Conclusions . ... 143

II. Correlation between the inception of hearing and the growth of the cochlea

Observation 146

Discussion 152

Conclusions 155

III. On the growth of the largest nerve cells in the ganglion vestibulare

Material and technique 156

Observations 156

Discussion 165

Conclusions 168

Final summary 169

Literature cited . . . 171


Introduction

Since Alphonse Corti, in 1851, published his famous work on the cochlea of mammals, studies on this organ have been made by many authors and have produced fairly concordant results. Concerning the postnatal growth of the internal ear, however, systematic studies are lacking. Especially is there no investigation, so far as I know, on the growth of the nerve cells in the ganglion spiral, not even in the great work of Retzius. ('84).

It was the special object of these studies, therefore, to follow the growth of the cells forming the spiral ganglion from birth to maturity and to correlate the changes in them with the appearance of the functional responses and with the structural changes in the membranous cochlea. In the course of this investigation studies were made also on the cells of the ganglion vestibulare, in order to see whether these cells differed in their growth from the cells in the spiral ganglion. Both of these ganglia are situated in the course of nervus acusticus, but have, as is well known, entirely different functions.

Thus determinations have been made on the diameters of the cells of the ganglion spirale and of their nuclei at different ages; of the nucleus-plasma ratios and of then* growth in relation to those of other portions of the membranous cochlea. For the cells of the vestibular ganglion similar determinations were also made. Finally, these results have been compared with those obtained from the study of other craniospinal ganglia in the albino rat.

In presenting my results I shall begin with a description of the changes in the larger portions of the membranous cochlea and pass from these to the cell elements themselves, and then to the observations on the ganglion cells and to the correlation between hearing and the growth of the cochlea.


Material

For the present studies forty male and thirty female albino rats were used, representing every phase of postnatal growth and having approximately standard body weights. These were all from the colony of The Wistar Institute, and were sometimes from the same, and sometimes from different litters.

At first all these rats were tested for their ability to hear and their equilibrium, and it was ascertained that after about twelve days of age, or somewhat earlier, they responded positively to the test for hearing. Such examinations were deemed necessary, to make certain that the rats used were normal.

I have arranged the animals thus tested in fourteen groups according to age, each group having five individuals in it. Serial sections from all these cochleas were made by methods to be given later. Most of them were in the plane of the vertical axis of the cochlea, but some were at right angles to it.

From the former I selected four ears in each group for the study of the growth of the cochlea. For the study of the growth of the ganglion vestibulare, I have used for the most part the same specimens. For the study of the sections at right angles to the vertical axis of the cochlea, sections from one ear of each group were used.

Technique

In order to obtain good preparations of this delicate organ, the method of vital fixation (injection under anaesthesia) was used. The method employed, and which proved almost ideal, was that introduced by Metzner and Yoshii ('09), Siebenmann and Yoshii ('08) and somewhat improved by Sato ('17). After the animals had been tested to make sure that they were quite normal, the fixing solution was injected through the aorta under ether. The brain was then carefully removed, care being taken not to drag the trunk of the nervus acusticus, as noted by Nager ('05), and the bulla tympanica was opened to allow the further penetration of the fluid.


The bony labyrinth with its surrounding bones was then placed in the fixing solution for two weeks, the fluid being renewed every day.

The fixing solution which I used consists, according to Yoshii ('09), of

10 per cent formol 74 parts

M tiller's fluid 24 parts

Glacial acetic acid 2 parts

According to Tadokoro and Watanabe ('20), this solution is one of the best, ranking with that of Wittmaack ( '04, '06) and that of Nakamura ('14).

This injection method is sometimes difficult to apply to very young rats on account of the small size and the delicacy of the vessels. When injection failed in very young animals, then immediately the head was cut off and put directly in the fixing fluid. Owing to the incomplete calcification of the very young cochlea, the fixing solution enters rapidly and fixes the deepseated organs in good condition. Since the parts of the internal ear are not yet well developed in the very young rats, they do not suffer from this method of fixation as do the older cochleas.

Indeed, no differences are to be seen between the sections prepared by vital fixation and by decapitation in very young rats.

For decalcification I have employed the following solution during three days, renewing it every day.

Decalcifying fluid

5 per cent aqueous nitric acid 49 parts

10 per cent formol 49 parts

Glacial acetic acid 2 parts

After the specimens had been washed in running water for three days, they were passed through the alcohols from 50 to 97 per cent. For the imbedding I have used 'parlodion' with good results. Here it is to be mentioned that all the cochleas were treated in the same way, even unossified cochlea being passed through the decalcifying fluid, so that there should be absolutely no differences in treatment.


The next important matter is the determination of the plane of the section. For the measurement of growth changes it was necessary to obtain corresponding sections from the several cochleas. In an organ like that of Corti, which changes in its details from one end to the other, however, it is very difficult to accomplish this, but I believe that I have overcome most of the difficulties.

After much testing, I found that a section parallel to the under surface of os occipitale in the fronto-occipital direction runs nearly exactly parallel to the axis of the modiolus of the cochlea. In order to get the same direction from right to left, I have taken as the standard the transverse plane of the under surface of the os occipitale, controlling the direction of the section with a magnifying glass. Thus nearly the same radial direction and nearly corresponding places in the cochlea were obtained in the several series of sections. This makes possible a trustworthy comparison of the measurements and drawings.

The cross-section of the cochlea was gotten by making the plane of the cut transverse to the axis of the modiolus. To get the corresponding levels is difficult. At first I divided all the serial sections by 2^, which is the number of complete turns in the cochlea of the albino rat. Next, from the number of the slides representing each turn, I determined nearly the corresponding level in the cochlea according to age.

All the sections were 10;x in thickness. The sections were stained for the most part with haematoxylin and eosin, but sometimes by Heidenhain's iron haematoxylin or the iron haematoxylin and Van Gieson's stain. For the measurements, however, only the sections stained with haematoxylin and eosin were used.

For the examination of the larger parts of the cochlea and their relations, the sections were projected on a sheet of paper by the Leitz-Edinger projection apparatus, at a magnification of exactly a hundred diameters, and the outline of the image accurately traced. The remaining measurements of the ganglion cells and the smaller portions of the cochlea were made directly under the microscope. The measurements made on the tympanic wall of the cochlea are somewhat complicated, but by the aid of figures 1 and 2 they may be explained. In figure 1 lines 1-1, 1-1'. 2-2, 3-3 indicate, respectively, the height of the arch of Corti, of the tunnel of Corti, of the papilla spiralis (Huschke) at the third series of outer hair cells, and of Hensen's supporting cells, respectively, above the plane of the membrana basilaris.

Lines 4-4' which are the extensions of the surface of the lamina reticularis and of the membrana basilaris, subtend the angle 8.

To get the exact measurements of the radial breadth of the membrana tectoria is very difficult, if not impossible, because it is sinuous in its course; moreover, it differs in thickness from point to point. Therefore, it has been variously described by different authors. Intra vitam fixation tends to prevent distortion. We divide the membrana tectoria, figure 1, into two portions, the first or inner (7-7'-9-9') and the second or outer (5-5 '-7-7') or outer zones of Retzius; each of these is again divided in two at 6-6' and 8-8', as shown in figure 1.

I have measured the radial distance of each portion and added all four together. This total approximates the natural radial breadth of this membrane, and since the sections have all been prepared in the same way and examined by the same method, the relations during growth can be followed.

In figure 2, 1-1 and 2-2, mark the length of the inner and outer pillar cells, respectively, from base to the point, which is situated just under their junction. It is to be noted here that the term ' pillar cell ' here applies to the pillars in the strict sense and does not include the associated cells.

Distances 3 and 7 in figure 2 show the basal breadth of the inner and outer pillars, respectively. The former is identical with the distance between the habenula perforata and the outer corner of the inner pillar after the inner corner of the pillar has reached the habenula perforata, but there is some difference between the two distances in very young rats. Distance 4 is that between the habenula perforata and the inner corner of the outer pillar; distance 5 is that between the habenula perforata and the outer corner of the outer pillar. The latter represents at the same time the radial breadth of the zona arcuata of the membrana basilaris.



Fig. 1 Showing the localities for the measurement of each part of the tympanic wall of ductus cochlearis in the albino rat, 100 days old radial vertical section. 1-1, height from the basal plane to the surface of pillar cells; 1-1', greatest height of the tunnel of Corti; 2-2, height of papilla spiralis at the third series of the outer hair cells; 3-3, height of Hensen's supporting cells; 4~4', 4 indicates the extension of the membrana basilaris and 4' the extension of the lamina reticularis. The two lines subtend the angle 0. The radial breadth of the membrana tectoria is taken as the sum of the four segments between the lines 5-5' and 9-9'.

Fig. 2 Showing the method of measurement for several parts of the tympanic wall of the ductus cochlearis in the albino rat, 100 days old. 1-1, length of inner pillar cell without head; 2-2, length of outer pillar cell without head Distance 3 shows radial distance between habenula perforata and the outer corner of inner pillar at base after twelve days of age this equals the radial basal breadth of inner pillar. Distance 4, radial distance between habenula perforata and the inner corner of outer pillar at base. Distance 5, radial breadth of the zona arcuata (Deiters') of membrana basilaris, and at the same time it indicates radial distance between habenula perforata and the outer corner of outer pillar at base. Distance 6, radial distance between the outer corner of inner pillar and the inner corner of outer pillar at base. Distance 7, radial basal breadth of outer pillar. Distance 8, radial distance between the habenula perforata and outer corner of inner pillar cell at base. Distance 9, radial basal breadth of the outer pillar cell. Distance 10, radial breadth of zona pectinata of the membrana basilaris. Distance 11, radial breadth of entire membrana basilaris.

Fig. 3 Showing the general outline of the cochlea in the radial vertical section albino rat, 100 days of age.



Abbreviations

Line 1, 1, distance between two basal L.L.S., limbus laminae spiralis

spiral ligaments L.S., ligamentum spirale

Line 2, 2, distance between two apical L.S.O., lamina spiralis ossea

spiral ligaments M.T., membrana tectoria

7, first turn N.C., nervus cochlearis

II, second turn O., bone

///, third turn P.S., papilla spiralis

IV, fourth turn S., stria vascularis

D.C., ductus cochlearis S.T., scala tympani

G.S., ganglion spirale S.V., scala vestibuli G.V., ganglion vestibulare


Distance 6 is that between the outer corner of the inner pillar and the inner corner of the outer pillar. Distance 8 is that between the habenula perforata and the outer corner of the inner pillar cell. Distance 9 shows the radial basal breadth of the outer pillar cell plus the outer pillar. Distance 11 shows the radial breadth of the membrane basilaris comprising distance 5 (zona arcuata) and 10, which is the radial breadth of the zona pectinata of the membrana basilaris.

II. Correlation Between the Inception of Hearing and the Growth of the Cochlea

The present study aims merely to compare in the rat the size of each element of the cochlea just before and just after the appearance of hearing and to ascertain the changes in the cochlea which take place during this phase. The rats which have sense of hearing show the so-called ' Ohrmuschelreflex 'of Preyer and other responses to auditory tests. Both the guineapig and rat react most evidently to sounds. The former animal responds usually five to six hours after birth. In the rat, however, the development of the function is, as already stated, relatively retarded and usually first appears at about ten days of age.

To test the presence of hearing there are several methods, as for example, Preyer V Ohrmuschelreflex' and the reflex closure of the eyelid, and these I used in making my observations. As the source of the sound I selected the hand clap, a whistle (Triller-pfeife, about c 4 ) and a low sound made by drawing in the breadth with nearly closed lips (about c 1 ).

Since it is my purpose merely to determine the first appearance of a response to sound, it is not nescessary to carry out such refined examinations as did Hunter ('14, '15, '18) Watson ('07), and others on white rats, and Marx ('09) on the guineapig, nor was it necessary to use the tuning-fork which by the way is not so good for tests on animals as for those on man. Since sometimes we may have a defect of hearing in animals, as shown by many investigators, it was deemed necessary to use several sources of sound and to take care not to produce ah* currents striking the test animal or to touch it in any way. For this purpose a large sheet of glass was placed between the source of sound and the rats to be tested. While the rat was resting I suddenly produced the sound and noted whether the rat responded. When the animals already had their eyes open the test was made from behind to avoid visual reflexes.

Observations

Rats at birth show no response to auditory stimuli. Most of them respond at twelve days of age very clearly, sometimes at ten to eleven days Under certain circumstances, the time of the reflex can be rather accurately noted. For example, while in the morning at ten days no reflex was noted it was present in the evening of the same day. Fortunately, I obtained five nine-day-old rats belonging to one litter and in nearly the same condition of nourishment and developnent. One of these responded to the test very evidently at noon on the ninth day, but the others did not. The sound which was effective was fairly intense, but to a faint and low-pitched sound this rat did not respond. In this case the external auditory canal was open. In the others there was in some a small open canal, but more or less closed by a cellular plug. In the latter cases I removed this obstruction without much difficulty or damage by washing, yet no reaction could be obtained to the stimuli. As it was to be expected, that also in the latter the reflexes would very shortly appear, all the cochleas of these young rats, both the not-hearing and hearing, were fixed by the method previously described and later examined.

In chapter 1, in which I followed the growth changes in the constituents of the membranous cochlea and in its ganglion cells from birth to maturity, including ' not hearing ' and ' hearing ' rats, very evident differences were observed in rats between nine and twelve days of age. In view of this, it will be of interest to compare the measurements obtained from the 'not hearing' and 'hearing' rats nine days old and members of the same litter. From the differences thus obtained we can conclude concerning the developmental changes in the cochlea requisite for the first appearance of hearing, provided there are no obstacles in the sound-conducting apparatus or deficiencies in the central organ.

In table 113 are given the values for the size of the several constituents of the cochlea 'from a rat which did not hear and one which did, at nine days. The former data are the averages from four cochleas, while the latter are from two. The table shows in a striking way that where there is a significant difference. The values obtained from the rat which could hear are usually larger than those of the rat which could not hear.

Among these measurements we see sometimes very marked and sometimes only slight differences. Only the radial distance between the labium vestibulare and the inner edge of the head of the inner pillar cell in the first two turns and the diameter of the nuclei of the inner and outer hair cells are in the former smaller than in the latter. In both instances, however, these smaller


TABLE 113

Comparison of the dimensions of the constituents of the cochlea in a hearing rat (H.) with those in a rat not hearing (N.) at nine days of age measurements

in micro


BAT


AGE


BODY WEIGHT


(N.) (H.)


days 9 9


grams 10 11


(N.) (H.)


1430 1434


Average


distance between two spiral ligaments



Breadth of membrana tectoria



TURN I


II


III


IV


Average



Th ids ness


(N.) (H.)


243

242


270 268


304 308


306 314


281 283



27 27


Breadth of membrana basilaris



TURN I


II


III


IV


AVERAGE


ZONA ZONA ARCUATA PECTINATA


(N.) (H.)


169 171


189 186


202 214


201 204


191 196


79 112 93 103


Distance between the habenula perforata and the outer corner of the inner hair cell



TURN I


II


III


IV


AVERAGE



(N.) (H.)


38 40


38 42


44

58


49 60


42 50


Distance between habenula perforata and the outer corner ol the outer pillar cell at foot*



TURN I


II


ill


IV


Average



(N.) (H.)


70

79


76

88


86 103


86 102


79 93


Height of greater epithelial ridge



TURN I


II


III


IV


AVERAGE



(N.) (H.)


36 42


40 43


41

48


42 50


40 46


Distance between the labium vestibulare and the habenula perforata



TURN I


II


III


IV


Average



(x.)

(H.)


83

85


108 104


137 140


145 150


118 120


GROWTH OF THE INNER EAR OF ALBINO RAT


149


TABLE 113 Continued

Distance between the labium vestibulare and the inner edge of the head of the

inner pillar cell



TURN I


II


III


IV


Average



(N.) (H.)


94

78


131

108


168 170


179 210


143 142


Height from basal plane to surface of pillar cells



TURN I


II


III


IV


AVERAGE



(N.) (H.)


32 40


33

42


35

45


36 45


34 43


Height of tunnel of Corti



TURN I


II


III


IV


AVERAGE



(N.) (H.)



20



18



14



11



16


Height of papilla spiralis at the third series of outer hair cells



TURN I


II


III


IV


AVERAGE



(N.) (H.)


28 42


28 43


27 39


28 36


28

40


Height of Hensen's cells



TURN I


II


ill


IV


AVERAGE



(N.) (H.)


20 42


23 45


23

38


24 30


23

39


Angle of lamina basilaris with plane of membrana basilaris degrees



TURN I


II


HI


IV


AVERAGE



(N.) (H.)



+7



+4



-8


7




Length of the inner and outer pillar cells



INNER

TURN I


II


III


IV


AVERAGE




(N.) (H.)


35 36


39 39


41 42


40 45


39

41



OUTER TURN I


II


III


IV


AVERAGE


WEIGHTED AVERAGE


(N.) (H.)


26 45


26

54


29 50


29 40


28 47


30 46


Volume of inner and outer hair cells



INNER: AVERAGE


OUTER: AVERAGE


WEIGHTED AVERAGE


(N.) (H.)


1798 1815


1277 1279


1407 1428


150


ANATOMICAL AND PHYSIOLOGICAL STUDIES ON


TABLE 113 Concluded Diameter of nuclei of the inner and outer hair cells



INNER: AVERAGE


OUTER: AVERAGE


WEIGHTED AVERAGE


(N.) (H.)


8.3 8.2


8.0 7.4


8.1

7.6



DEITERS' CELLS:

VOLUME M '


DIAMETER OF NUCLEI


LENGTH OF CELL BODY


PHALANGEAL PROCESS


(N.) (H.)


518 1193


7.0

7.2


14 32


22 22


Ganglion spirale: diameters computed



CELLS


NUCLEI


(N.) (H.)


13.6 13.7


8.5 8.6


values are marks of maturity. These changes in size accord with the results given in chapter 1 at twelve days of age, though there are some differences between them in the absolute values.

Figures 7 and 8 illustrate the outlines of the tympanic wall of the membranous cochlea in nine-day-old rats which could not and could hear, respectively. These figures have been drawn from the corresponding sections at the beginning of the middle turn of the cochlea and are comparable with figures 3 to 6 and 9 to 12. On comparing figures 7 and 8, the more noticeable differences appear to be the following.

The membrana tectoria is a bit longer in the hearing rat. The appearance and the position of it with reference to the surface of the papilla spiralis is also different. In the not-hearing cochlea it has an infantile look.

The outer end of the main part does not yet reach the second row of the outer hair cells and connects with the Hensen's prominence by a thick thread. There are also many fine fibers to be seen between the basal surface of the membrane and the papilla. In the hearing rat the fine fibers are absent. The membrane reaches already the row of the outer hair cells and there is a strong connection between this part and the terminal

ame (Schlussrahmen) of the lamina reticularis by a thick

read as shown in figure 8 Thus the position of the membrane above the papilla depends a little bit upon the increase of the length of the membrane itself, but chiefly upon other factors such as the inward shifting of the papilla. The membrana basilaris as a whole shows a small increase o" breadth in the hearing rat. The zona arcuate, however, increases much in its breadth, while the zona pectinata rather decreases. This is due to the development of the pillar cells. The base of the inner and outer pillar cell spread much on the membrane. At the same time the length of the cells, especially of the outer, increases nearly twice as much as in the not-hearing rat.

Thus the foot of the outer pillar cell moves out ward, as Bottcher ('69, 72) stated, while the inner corner of the inner pillar cell does not move in any way, as the habenula perforata stands at a fixed point. This results in a change in the form of the arch of Corti. The hitherto outward inclined arch tends to bend inward and between both inner and outer cells arises a space, the tunnel of Corti. The appearance of the tunnel seems to have some relation to hearing. The tunnel is always present in the cochleas of hearing rats. Sometimes the tunnel is present in the lower turns, but not in the upper turns in the not-hearing rats. We can say, therefore, that it probably appears through all the turns before the special function of the cochlea begins. In this way the zona arcuata of the membrana basilaris increases its breadth.

The next striking change is the rapid increase in the size of the Deiters' cells, Hensen's cells, and the resultant change of the form, with an inward shifting, of the papilla spiralis.

The Deiters' cells increase their height very rapidly; the length of the cell body becomes over twice that in the not-hearing rat, but the processus phalangeus changes only slightly. Hensen's cells develop also, but not so much as Deiters' cells. The papilla spiralis thus increases in height. On the other hand, the greater epithelial ridge vanishes inwards from the inner supporting cells and appears as a furrow the sulcus spiralis internus. Through the pressure of these outward-lying cells the papilla spiralis swings inward as a whole, without really moving on the membrana basilaris. The lamina reticularis becomes inclined inward instead of outward and subtends a slight angle with the plane of the membrana basilaris. The distance from the labium vestibulare to the inner edge of the head of the inner pillar cell becomes smaller through the inward shifting of the papilla.

In the hair cells and the cells of the ganglion spirale we see a smaller difference between the hearing and not-hearing rats. Only the diameter of the nuclei of the hair cells in the hearing rat diminishes a little, as it continues to do in the adult cochlea.

All the changes just enumerated begin at the base of the cochlea and progress to the apex. Therefore we see the high and outward ascending papilla spiralis in turn I, while in the upper turns the papilla is not yet so developed, is smaller in all the constituents, and shows in general the characters of a younger and less mature cochlea conditions which disappear with age. This upper and immature part seems not to respond to the test for hearing. Indeed, my testing result is positive for sounds of high pitch, but not for low pitch. Therefore we conclude that the papilla spiralis develops functionally from base to apex and that when the papilla spiralis has developed in the basal turns, but not in the upper turns, it responds to sounds of high pitch alone.

Discussion

If we assume that our tests for hearing are trustworthy, then the differences between the size of the constituents of the cochlea in nine-day-old rats which could and could not hear will indicate what developmental changes in the cochlea of the albino rat are necessary for the appearance of the hearing reflex. Whether all the differences found by us are necessary is difficult to determine, and the problem is open for further study; but as the matter stands, our results give the closest correlation between structural changes and the appearance of function which has as yet been reported.

Kreidl and Yanase ('07) studied the differences between the not-hearing and hearing rat and summarized their results on page 509: "Kurz vor Eintritt des Horreflexes ist das Cortische Organ im wesentlichen fertig ausgebildet. " They publish no measurements nor data. The condition of the development of the organ of Corti described as 'fertig ausgebildet' is not sufficiently precise.

Further, on the same page they say, "Der auffalligste und, soweit die Untersuchungen bis jetzt eregben haben, einzige Unterchied, der zwischen dem anatomischen Bild des Labyrinthes eines neugeborenen Tieres, das den Reflex eben nochnichtaufweist, und dem eines solchen, dasdenselben zum ersten Male eben erkennan lasst, ist der, dass beim ersteren noch ein Zusammenhang zwischen Cortischem Organ und Cortischer Membran besteht, beim letzteren dagegen dieser Zusammenhang bereits gelost oder gelockert ist." Their observation is quite different from mine. In my case the papilla spiralis shows in the development of its constituent elements pretty large differences between the not-hearing and hearing rats. Therefore it seems probable that the changes in the growth and form of the papilla just before the first appearance of the special function, take place very quickly. Also we cannot agree to then* statement concerning the relation of the membrana tectoria to the papilla spiralis. In our preparations there is still a connection of the membrane with the terminal frame of the lamina reticularis through a thick thread in the cochlea of the rat which could hear (fig. 8) and also in that of the rat which could not hear (fig. 7).

This is a point on which opinions differ. While one opinion, represented by Kishi ('07) and others, is to the effect that this connection remains through life, the other, represented by Kolliker('67) and others, asserts the membrane projects free in the endolymph. I have never seen this connection in the adult cochlea, nor have I found such a connection of the membrane with the hairs of the hair cells, as Shambaugh ('10) described in the pig. In the young rats, at fifteen days for example, we very often see upon the terminal frame the broken remainder of this connecting thread. Whether this break arises through natural development or is the result of artificial manipulation it is hard to say. At any rate, Held's assertion ('90), that in an animal capable of hearing the membrana tectoria is never connected with the papilla spiralis, is not supported by my observation. That the freeing of the outer zone of the membrane is not absolutely necessary for the mediation of auditory impulses is demonstrated in the cochlea of birds, as shown by Hasse ('66), Retzius ('84), Sato ('17), and others. In these forms the membrane remains through life attached to the epithelial ridge.

My results agree with those of Hardesty ('15) on this point, though he obtained a tectorial membrane which floats free in the endolymph with its outer zone. Lane ('17) studied the correlation between the structure of the papilla spiralis and the appearance of hearing in the albino rat, but his description is brief and does not touch on this relation of the papilla to the tectorial membrane.

Thus the inception of hearing does not coincide with the detachment of the tectorial membrane from the papilla spiralis, but with the development of each constituent of the papilla spiralis and the membrane tectoria, as has been described. As these changes occur first at the base and then pass to the apex, the animal can perceive at first only the sounds of high pitch. One or two days later development is complete in all the turns, and then the rat can hear the sounds of lower pitch also. Thus the process of the development of the cochlea does not support the ' telephone theory' of audition, but on the contrary agrees with the conclusion that the papilla in different locations in the turns of the cochlea responds to sounds of a definite pitch, as Wittmaack ('07), Yoshii ('09), Hoessli ('12), and others have shown by experimental studies on the mammals.

Concerning the exact age of the first appearance of the function in the rat, there are several different statements. Lane ('17) found no response to sound before the twelfth day after birth, and on the sixteenth day he reports hearing well established. Kreidl and Yanase ('07) state that hearing begins in the rat at from twelve to fourteen days. My rats responded usually at ten to twelve days, but one at nine days. These differences depend in all probability on the vigor of the young during the first days of postnatal life, and it seems probable that exceptionally well-nourished young might develop precociously in this


GROWTH OF THE INNER EAR OF ALBINO RAT 155

respec t. The intensity of the stimulus is important in determining the hearing reflex, as Small ('99) has stated. In my cases the young rats responded very evidently to intense sounds, while they reacted weakly or not at all to those which were faint. Thus only the intense sounds were perceived by the rat of nine days.

Conclusions

1. The hearing reflex was never obtained in rats less than nine days of age.

2. At nine days a single rat, one of five in a litter, responded to a sharp sound like clapping the hands and to a whistle of high pitch; the other four did not respond. At the tenth day some of the four reacted, and at the twelfth day all could hear.

3. The hearing reflex probably occurs early in young rats that are vigorous and well nourished.

4. To obtain the first hearing reflexes it is necessary to have rather strong sounds of high pitch.

5. A comparison of the histological structure of the cochlea in rats of nine days, one of which could hear and the other could not, shows clear differences in its development of the cochlea. These consist not in the detachment of the tectorial membrane from the papilla spiralis, but in the degree of differentiation of the constituents of the papilla. The tectorial membrane is connected in both cases at its outer end with the terminal frame of the lamina reticularis by a thick thread. The papilla is more differentiated in the hearing rat in several characters. The tectorial membrane has reached with its outer end the outermost row of the outer hair cells, but in the not-hearing rat it has not yet reached the second row of the cells.

6. The form of the papilla and its relation to the surrounding structures, especially to the tectorial membrane, are in the hearing rat at nine days very similar to those in the rat at twelve days of age, though there are some differences between them in absolute size.

7. The freeing of the tectorial membrane from the papilla spiralis is not necessary to the appearance of the hearing reflex,


156 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON

but the differentiation of the papilla, its shifting inward, its change in form and position under the membrana tectoria, appear to be important.

8. Since the papilla develops from the base toward the apex, it first reaches in the lower turn a high degree of differentiation, and this part first begins to function. Therefore the rat can hear only sounds of high pitch when it first responds.

9. This result accords with that well-known fact that the papilla in the lower turn responds to sounds of a high pitch, while in the upper turn it responds to sounds of low pitch.

III. On the Growth of the Largest Nerve Cells in the Ganglion Vestibulare

Material and technique

The material used for the present study was in a great part the same that was employed for the studies reported in chapter 1, with the addition of some new specimens as shown in table 114 and table 94. In the slides obtained in the radial vertical section we see the vestibular ganglion cells situated in a single group at the radix of the cochlea (Fig. 3 G. V.). As four ears were used in each age group, four cell groups were examined at each age. Besides these fourteen age groups, six rats used for cross-sections, in chapter 1, were also included.

The measurements were made in the same way and under the same conditions as those described earlier for the cells of the spiral ganglion. Since the ganglion vestibulare consists of two parts, the ganglion vestibulare superius and inferius, the ten largest cells were taken from each part and the results averaged.

Observations

By way of introduction I wish to say a word about equilibration in the young rat. The young just born crawl over on each other and seem to attempt to find the mothers nipples. They turn the head to and fro and roll over on the flanks, belly, or back. While resting they take their normal position or lie on the side. When turned on their backs they endeavor to regain the normal


GROWTH OF THE INNER EAR OF ALBINO RAT


157


position. The fore legs are of more use than the hind in making readjustments. The tails hang down between the hind legs.

TABLE 114

Data on rats used for the study of the cells of the ganglion vestibulare (radial section).

See also table 94


AOB


BOOT WEIGHT


BODY LENGTH


BEX


BIDE


AUDITOHT RESPONSE


days


grams


mm.





1


5


44


9


R.




4


44


9


R.




5


48


d 1


R. L.



3


9


60


<?


R. L.




8


56


9


R. L.



6


10


64


a


R.




10


64


9


R. L.




11


62


(7


R.



9


11


67


<?


R. L.


+



9


58


9


R.




10


57


tf


R.



12


13


70


d 1


R. L.


+



12


68


9


R.


+



15


72


c?


R.


+


15


13


74


d"


R. L.


+



14


75


9


R. L.


+


20


30


.96


d 1


R. L.


+



28


94


c?


R. L.


+


25


34


101


9


R. L.


+



34


100


d 1


R. L.


+


50


58


121


9


R. L.


+



43


104


(f


R. L.


+


100


146


176


c?


L.


+



103


154


9


L.


+



101


152


9


R. L.


+


150


154


184


9


R. L.


+



189


191


c?


R.


+



199


192


d 1


R.


+


260


137


162


9


R.


+



140


171


9


R. L.


+



134


178


9


R.


' +


367


205


202


rf


L.


+



170


182


9


L.


+



179


196


9


R. L.


+


546


282


222


d 1


R. L.


+



227


204


d 1


R. L.


+


At three days they move and crawl very actively. They tend to assume the normal position. When rolled over on the back or side they succeed in regaining the normal position in


158


ANATOMICAL AND PHYSIOLOGICAL STUDIES ON


a few seconds. When six days old the rats have fairly well coordinated movements. They use their fore and hind legs effectively and in the same way. When the mother 's body touches them they respond quickly by searching for the nipples.

At nine days they move much more quickly and the movements are well coordinated. .Though the eyes are still closed, they


TABLE 115

Diameters of the cells and their nuclei in the ganglion vestibulare in radial vertical section

(Chart 43)


AGE


BODY WEIGHT


DIAMETERS IN M


CELL BODY


NUCLEUS


Long


Short


Computed


Long


Short


Computed


days


grams








1


5


21.2


19.5


20.3


12.4


11.1


11.7


3


9


23.7


22.2


22.9


12.5


11.6


12.0


6


11


24.0


22.1


23.0


12.3


11.9


11.9


9


10


24.8


23.0


23.9


12.5


11.6


12.0


12


13


24.9


23.0


23.9


12.5


11.7


12.1


15


13


24.8


23.0


23.9


12.5


11.6


12.0


20


27


25.0


23.3


24.1


12.3


11.6


11.9


25


34


25.2


23.6


24.4


12.5


11.8


12.1


50


50


25.6


23.6


24.5


12.5


11.6


12.0


100


112


25.5


23.9


24.7


12.8


11.9


12.3


150


174


25.4


23.5


24.4


12.8


11.6


12.2


260


138


25.8


23.4


24.6


12.4


11.7


12.0


367


184


26.2


24.9


25.5


12.9


11.8


12.3


546


255


26.5


24.2


25.3


12.8


11.8


12.2


Ratios 1

-367 days




1 1.3




1:1.1


1546 "




1.2




1.0


15367 "




1.1




1.0


crawl toward the object sought. When turned over on the back they regain the normal position immediately. While resting they lie on their bellies with all the legs spread well apart.

Twelve-day-old rats, though the eyes are still closed, go to and fro actively with good coordination, but are somewhat slower than the adults. The body loses its fetal red color through the development of the first hairs. After this period the rats do not differ greatly from the adult in their general behavior.


GROWTH OF THE INNER EAR OF ALBINO RAT


159


The growth changes in the ganglion cells of the ganglion vestibulare. In table 115 (chart 43) are given the values for the diameters of the cell bodies and their nuclei in the largest cells of the ganglion vestibulare. At the bottom of the last column for the cell body and for the nucleus, respectively, are recorded the ratios at 1 to 367, 1 to 546, and 15 to 367 days. The last ratio was taken


25

a

20 15 10


  • GEDAYSH




25


50


5O 1OO 2OO 30O 4OO 5OO


Chart 43 The diameter of the largest cell bodies and of the nuclei from the ganglion vestibulare. table 115.

Cell bodies. -.-.-.-.-. Nuclei.

to facilitate a comparison with the data in table 118 which begin at 15 days.

Looking at the ratios of the cell bodies and of their nuclei from 1 to 546 days, it appears that the ganglion cells increase 1.2 in diameter, while their nuclei have only a very slight increase, and therefore the ratio is 1 : 1.0. This increase in the cell bodies is continuous from birth to old age, but after fifteen days is very slow. In the nucleus we see a slight increase at the earlier


160 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON

ages, after which the values are nearly constant. This means that after birth the size of the cell bodies and their nuclei does not increase so much as do those of the spiral ganglion cells, or, expressed in another way, the cells in the vestibular ganglion have developed earlier than those of the spiral ganglia and at birth have already attained nearly their full size.

On the comparison of the diameter of the cell bodies and their nuclei in the nerve cells of ihe ganglion vestibulare according to sex. For this purpose twelve age groups of albino rats were used. In seven cases we have two cochlea in each group in the same sex, in which the average value is recorded. In table 116 are entered the values for these diameters and at the foot of the table the data are analysed. They reveal no evidence of a significant difference in the diameters according to sex.

On the comparison of the diameters in the cell bodies and nuclei of the nerve cells in the ganglion ves ibulare according to side. For the present study fourteen age groups were employed. As indicated in table 117, the data in five instances are based on the average of two cochleas of the same side. Table 117 enables us to make the comparison of the diameters of the cell bodies and their nuclei on both sides, and the analysis of the data given at the bottom of the table shows that there is no difference in these characters according to side.

On the morphological changes in the cells of the vestibular ganglion. Figure 14 illustrates semi-diagrammatically the ganglion cells in the vestibular ganglion of the albino at birth, 20 and 367 days of age. These figures, as in the ganglion spirale, have been magnified 1000 times and the absolute values of the diameters are given in table 115.

As seen in figure 14, both the cell body and the nucleus are at birth already well developed and more precocious in their development than the cells in any of the other cerebrospinal ganglia thus far examined. The cytoplasm is relatively abundant and the Nissl bodies are present, though both of these characters become more marked later.

The nucleus is also large, the chromatin somewhat differentiated and the so-called 'Kernfaden' often occur. Generally speaking,




I Day


20 Days


14


366 Days


Fig. 14 Showing setrii-diagrammatically the size and the morphological changes in the ganglion cells in the ganglion vestibulare of the albino rat at the age of 1, 20 and 366 days. All cell figures have been magnified 1000 diameters.


GROWTH OF THE INNER EAR OF ALBINO RAT


161


therefore, the cells have the characteristics of the mature elements though they stain less deeply than in the adult. At twenty days of age the cell body is enlarged and fully mature. The Nissl

TABLE 116

Comparison of the diameters of the cells and their nuclei in the ganglion vestibidare

according to sex


AGE


BODY WEIGHT


NUMBER OF RATS


8EX


COMPUTED DIAMETERS


Cell body


Nucleus


days


grams






1


6


2


f


20.8


11.9





9


19.9


11.5


3


9


2


tf


21.7


11.8



8


2


9


23.8


12.2


6


11


2


tf


22.7


11.9



10


2


9


23.1


12.1


9


11


1


d*


23.8


12.5



9


1


9


23.8


12.1


12


15


1


cf


24.4


12.2



12


1


9


23.1


11.9


15


13


2


cf


24.3


12.2



13


2


9


23.4


11.9


20


30


1


cf


24.7


11.9



19


1


9


24.6


12.6


25


34


2


d"


24.4


11.9



34


2


9


24.4


12.4


50


43


2


cT


26.1


12.4



58


2


9


22.6


11.4


100


146


1


<?


26.3


12.8



103


1


9


23.4


12.6


150


194


2


rf 1


24.4


12.5



154


2


9


24.4


12.0


365


205


1


<f


24.2


11.7



170


1


9


24.6


12.1


Average for male


24.0


12.1


Average for female


23.4


12.1


Males larger


6


7


Females larger


3


5


Males and females equal


3




bodies are more differentiated and the nucleus is mature, though it shows only a slight increase in size.

At 367 days the histological structures appear much as at twenty days, but the diameters of both the cell body and the nucleus have very slightly increased. This is in contrast to the change which occurs in the cells of the spiral ganglion.


162


ANATOMICAL AND PHYSIOLOGICAL STUDIES ON


In order to study the form of the cells of the ganglion vestibulare the measurements also were made on the cross-sections. Table


TABLE 117


Comparison of the diameters of the cells and their nuclei in the ganglion vestibulare according to side


AGE


BODY WEIGHT


NUMBER OF RATS


SIDE


COMPUTED DIAMETERS


Cell body


Nucleus


days


grams






1


4


1


R.


20.1


12.0



5


1


L.


22.0


12.5


3


9


2


R.


23.0


11.8





L.


22.6


12.3


6


10


1


R.


23.2


12.1





L.


23.5


12.0


9


11


1


R.


25.1


12.3





L.


23.8


12.5


12


15


1


R.


24.4


12.2



13


1


L.


25.1


12.5


15


13


2


R.


24.2


12.2





L.


23.6


11.9


20


30


1


R.


24.7


11.9





L.


23.5


11.4


25


34


2


R.


23.9


12.1





L.


24.9


12.2


50


50


2


R.


23.1


11.6





L.


25.6


12.3


100


101


1


R.


25.0


12.0





L.


24.8


11.7


150


199


1


R.


25.1


12.8



154


1


L.


25.4


12.5


263


140


1


R.


26.5


12.3





L.


25.1


12.4


368


179


1


R.


27.2


12.6





L.


26.2


13.0


546


255


2


R.


26.0


12.4





L.


24.6


12.0


Average right side


24.4


12.2


Average left side


24.3


12.2


Right larger


8


6


Left larger


6


8


118 (chart 44) shows the results. Looking at the ratios of 15 to 371 days, we see the same rate of increase in the cell bodies and the nuclei as that in the radial section; i.e., in the cell bodies 1 : 1.1 and in the nuclei 1 : 1.0. Comparing the diameters at each


GROWTH OF THE INNER EAR OF ALBINO RAT


163


TABLE 118

Diameters of the cell bodies and their nuclei in the ganglion vestibulare, on crosssection (chart 44)




DIAMETERS M


AOK


BOOT WEIGHT


CELL BODY


NUCLEUS




Long


Short


Computed


Long


Short


Computed


days


grams








15


20


25.1


22.8


23.9


12.4


11.6


12.0


20


27


25.2


23.4


24.3


12.5


11.7


12.1


25


39


25.2


24.0


24.6


12.3


12.0


12.1


100


95


26.6


24.7


25.6


12.8


11.8


12.3


150


169


26.7


24.7


25.7


13.0


11.7


12.3


371


220


26.8


25.3


26.0


12.8


11.8


12.3


Ratio 15-371 days 1:1.1




1 :1.0


25


20


15


10


25


50


50 10O 20O 300 40O 5OO


Chart 44 The diameters of the cell bodies and of their nuclei from the ganglion vestibulare, after fifteen days (cross-section), table 118. Cell bodies. -.-.-.-.-. Nuclei.


164


ANATOMICAL AND PHYSIOLOGICAL STUDIES ON


age in both the radial and cross-sections, they are almost the same, with a slight tendency for the cells in the cross-section to give higher values, which suggests that the long axes of these cells tend to lie in the plane of the section.

On the nucleus-plasma relations of the ganglion cells in the ganlion vestibulare. In table 119 are entered the computed diameters of the cell bodies and their nuclei in the radial section, and in the last column the ratios of the volume of the nucleus to that of the cytoplasm obtained by the method previously given. As

TABLE 119

Nucleus-plasma ratios of the cells in the. ganglion vestibulare radial vertical section




COMPUTED DIAMETERS M


AGE


BODY WEIGHT


Cell body


Nucleus


Nucleus-plasma ratios


days 1


grams 5


20.3


11.7


1 :4.2


3


9


22.9


12.0


5.9


6


11


23.0


11.9


6.2


9


10


23.9


12.0


6.9


12


13


23.9


12.1


6.7


15


13


23.9


12.0


6.9


20


27


24.1


11.9


7.3


25


34


24.4


12.1


7.2


50


50


24.5


12.0


7.5


100


112


24.7


12.3


7.1


150


174


24.4


12.2


7.0


260


138


24.6


12.0


7.6


367


184


25.5


12.3


7.9


546


255


25.3


12.2


7.9


seen, the ratio is at birth relatively large, 1 : 4.2, and this increases with age, in the earlier stages considerably, but in the later, less rapidly. In the oldest age group it is largest, 1: 7.9.

On the cross-section the nucleus-plasma ratio is also progressive and the increase is very regular (table 120). Comparing the ratios in the radial with those in the cross-sections, they are found to be nearly the same at fifteen twenty and twenty-five days, but at the later ages those in the cross-sections are somewhat larger than in the radial. It is difficult to determine whether the ratios on the cross-section are really larger or whether the


GROWTH OF THE INNER EAR OF ALBINO RAT


105


result depends on the fact that the number of the cells here measured is only one-fourth of that measured in the radial section, and hence fewer cells of smaller size were included. At any rate, these ganglion cells in both the radial and crosssections of the cochlea appear to grow at about the same rate. The statistical constants for these cells and their nuclei are given in tables 121 and 122.

Discussion

The nerve cells in the ganglion vestibulare are, as seen from the above description, already well developed at birth both in size and histological structure. After that time they grow con TABLE 120

Nucleus-plasma ratios of cells of the ganglion vestibulare, in cross-section




DIAMETERS COMPUTED M



BOOT



AGE


WEIGHT






Cell body


Nucleus


Nucleus-plasma






ratios


days


grams





15


20


23.9


12.0


1 :6.9


20


27


24.3


12.1


7.1


25


39


24. ti


12.1


7.4


100


95


25.6


12.3


8.0


150


169


25.7


12.3


8.1


371


220


26.0


12.3


8.4


tinuously but slowly so long as followed. The increase from 1 to 546 days in the ratios of the diameters is in the cell body 1: 1.3, in the nucleus 1: 1.1, and is therefore very small. In the cerebrospinal ganglion cells and in the cells of the cerebral cortex, studied in the albino rat, there is no case which shows such a small rate of increase between birth and maturity. The following table 123 shows the ratios of increase which have been found.

It is to be noted that for the cells of the seventh spinal ganglion and the spinal cord, the ratios were taken from 17 to 360 days. If we had the ratios from 1 to 360 days, they would be without question much larger.

There are a few measurements on the size of the ganglion cells in the vestibular ganglion of various animals in the liter


166


ANATOMICAL AND PHYSIOLOGICAL STUDIES ON


ature. Schwalbe ('87) and Alexander ('99) report measurements on these cells in several animals, but for the reasons already given when considering the diameters of the cells in the ganglion spirale, the values obtained by the authors are not repeated here.

TABLE 121

Giving the mean, standard deviation and coefficient of variability, with their respective probable errors, for the diameters of the cells in the ganglion vestibulare, in radial-vertical section


AGE


CELL NUCLEUS


MEAN


STANDARD DEVIATION


COEFFICIENT OF VARIABILITY


days 1


Cell


20.1 0.16


1.46 0.11


7.3 0.55



Nucleus


11.7 0.11


0.99 0.07


8.5 0.64


3


Cell


22.6 0.14


1.33 0.10


5.9 0.44



Nucleus


11.9 0.07


0.63 0.05


5.3 0.40


6


Cell


22.8 0.13


1.23 0.09


5.4 0.41



Nucleus


11.9 0.05


0.43 0.03


3.6 0.27


9


Cell


23.6 0.16


1.48 0.11


6.3 0.48



Nucleus


12.0 0.0<9


0.82 0.06


6.8 0.52


12


Cell


23.6 0.14


1.28 0.10


5.4 0.41



Nucleus


12.0 0.06


. 59 . 04


4.9 0.37


15


Cell


23.6 0.13


1.21 0.09


5.1 0.39



Nucleus


12.1 0.06


0.60 0.05


5.0 0.38


20


Cell


23.9 0.16


1.54 0.11


6.5 0.49



Nucleus


11.9 0.10


0.90 0.07


7.6 0.55


25


Cell


24.2 0.16


1.48 0.11


6.1 0.46



Nucleus


12.1 0.08


0.74 0.06


6.1 0.46


50


Cell


24.1 0.30


2.80 0.21


11.6 0.88



Nucleus


11.8 0.09


0.86 0.06


7.3 0.55


100


Cell


24.3 0.20


1.86 0.14


7 . 7 . 58



Nucleus


12.2 0.09


0.86 0.06


7.0 0.53


150


Cell


24.1 0.18


1.70 0.13


7.1 0.53



Nucleus


12.2 0.09


0.83 0.06


6.8 0.52


260


Cell


24.3 0.26


2.45 0.18


10.1 0.76



Nucleus


11.9 0.07


0.67 0.05


5.6 0.42


367


Cell


25.2 0.22


2.07 0.16


8.2 0.62



Nucleus


12.3 0.09


0.88 0.07


7.2 0.54


546


Cell


25.0 0.19


1.80 0.14


7.2 0.54



Nucleus


12.1 0.09


0.81 0.06


6.7 0.50


On the differences between the growth of the cells in the ganglion spirale and ganglion vestibulare. The foregoing discussion has made plain that the vestibular ganglion cells grow not only in size, but also in histological structure very much before birth, while after birth they grow slowly though continuously. On the other hand, the spiral ganglion cells are relatively immature at


GROWTH OF THE INNER EAR OF ALBINO RAT


167


birth, but in the earlier stages after birth grow very rapidly, reach at twenty days their maximum size, and then diminish slowly. This great difference in the course of growth is probably related to the maturity of the functions of the animal.

TABLE 122

Giving the mean, standard deviation and coefficient of variability with their respective probable errors for the diameters of the cells in the ganglion vestibulare on cross-section


AGE

days


CELL NUCLEUS


MEAN


STANDARD DEVIATION


COEFFICIENT OF VARIABILITY


15


Cell


23.8 0.21


1.00 0.15


4.2 0.58



Nucleus


12.0 0.12


0.55 0.08


4.6 0.69


20


Cell


23.9 0.20


0.92 0.14


3.9 0.58



Nucleus


12.1 0.06


0.30 0.05


2.5 0.37


25


Cell


24.4 0.20


0.94 0.14


3.9 0.58



Nucleus


12.1 0.03


0.16 0.02


1.3 0.20


100


Cell


25.4 0.32


1.51 0.23


5.9 0.90



Nucleus


12.3 0.15


0.72 0.11


5.9 0.88


150


Cell


25.6 0.20


0.94 0.14


3.7 0.55



Nucleus


12.4 0.09


0.42 0.06


3.4 0.51


371


Cell


25.9 0.41


1.91 0.29


7.4 1.11



Nucleus


12.3 0.06


0.26 0.04


2.1 0.32


TABLE 123 Ratios of diameters between the ages given.



CEREBRAL CORTEX



DONALDSON AND



(SUGITA, '18)



NAOABAKA. '18


CELL GROUP


LAMINA


LAMINA


OA88ERIAN


SPIRAL


VESTIBULAR


7TH


EFFERENT



PYHA

GANO

GANGLION


GANGLION


GANGLION


SPINAL


SPINAL



MIDIS


LIONARIS


NITTONO


WADA


WADA


GANGLION


CORD





C20)





CELLS


Age









days


1-730


1-730


1-330


1-546


1-546


17-360


17-360


Cell









body


1 :1.6


1 : 1.6


1 : 1.69


1 : 1.6


1 :1.2


1 :1.3


1 :1.2


Nucleus


1.5


1.5


1.20


1.2


1.0


1.2


1.2


As a consequence, in the nucleus-plasma ratio there is also a large difference between the cells in the two ganglia. Table 124 shows this.

The ratio at birth in the ganglion vestibulare is large as compared with that in the ganglion spirale, but the increase in this ratio


168 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON

at 546 days is relatively slight as compared with what takes place in the cells of the ganglion spirale. It appears, therefore, that the cells in the vestibular ganglion are at birth in a more mature condition.

As to the correlation between the development of the ganglion cells and the equilibrium function, we have noted that the albino rats, even just after birth, show some sense of equilibrium, though the movements are lacking in coordination. With advancing age the balance of the body is held much better and all the movements gradually become coordinated. The histological structure and the size of the cells at birth suggest that they are functional at that time, and the later increase in the volume and maturity of the cells is accompanied by a corresponding

TABLE 124



GANGLION VESTIBULARE


GANGLION SPIRALE


Nucleus-plasma ratio at one day Nucleus-plasma ratio at 546 days


1 :4.8

7.9


1 : 1.3

4.2


increase in the functional development. When the tactile sense is well developed and the eyes open equilibrium is almost perfected. It is a well-known fact that these two senses have very intimate relations to the maintenance of equilibrium. In this case, as we might expect, the early development of a function is accompanied by an early maturing of the neural mechanism on which it depends.

Conclusions (for the ganglion vestibulare)

1. The measurements were taken on the largest nerve cells of the ganglion vestibulare in the radial section of the cochlea, and the developmental changes during portnatal growth studied in fourteen age groups, comprising four ears in each group. Further, in six age groups the cell size was determined in crosssections. The results have been given n tables 115 and 118 and charts 43 and 44.


GROWTH OF THE INNER EAR OF ALBINO RAT 169

2. The computed diameter at birth is 20.3 [x for the cell body and 11.7 ^ for the nucleus, and at 546 days, 25.3 and 12.2 n, respectively. Therefore the cells at birth are comparatively large and increase in size very slowly, but the increase is continuous.

3. The increase in the ratio of the cell body is as 1 : 1.3, of the nucleus as 1 : 1.1. We have between the same age limits no such small rate of increase in any other cerebrospinal ganglion studied in the albino rat. This small ratio indicates that the cells in the vestibular ganglion are well developed at birth.

4. We find no appreciable difference in the diameters of the cell bodies or the nuclei according either to sex or side.

5. Morphologically, the cells at birth are well differentiated. The form of the cells is ovoid.

6. The nucleus-plasma ratios are large at birth and increase regularly with age.

7. Comparing the development of the function of equilibrium with the growth of the cells, we see that these are correlated.

Final summary

This study is concerned with the age changes in the organ of Corti and the associated structures. The changes in the largest nerve cells which constitute the spiral ganglion and the vestibular ganglion, respectively, have also been followed from birth to maturity. On pages 116 to 124 are given the summary and discussion of the observations on the growth of the tympanic wall of the ductus cochlearis.

The conclusions reached from the study of the largest nerve cells in the ganglion spirale appear on pages 143 to 145. On pages 155 and 156 are presented the results of the study on the correlation between the response to sound and to the conditions of the cochlea.

Finally, the observations on the growth of the largest cells in the ganglion vestibu'are are summarized on pages 168 and 169.

It is not necessary to again state in detail the conclusions reached in the various parts of this study.

At the same time, if we endeavor to obtain a very general picture of the events and changes thus described, this may be sketched as follows:


170 ANATOMICAL AND PHYSIOLOGICAL STUDIES ON

Within the membranous cochlea there occurs a wave of growth passing from the axis to the periphery as shown in figures 4 to 13. The crest or highest point of the tissue mass appears at birth near the axis, in the greater epithelial ridge, and then progressively shifts toward the periphery, so that at maturity it is in the region of the Hensen cells. With advancing age the hair cells come to lie more and more under the tectorial membrane and the pillar cells seem to shift toward the axis.

At from 9 to 12 days the tunnel of Corti appears and the rat can hear.

All of these changes occur first in the basal turn and progress toward the apex. The mature relations are established at about twenty days. There are thus two waves of change in the membranous cochlea, from the axis to the periphery and the other from the base to the apex. The rat can usually hear at twelve days of age or about three days before the eyes open.

The largest cells in the ganglion spirale are very immature at birth, reach their maximum at twenty days, and after that diminish in size, slightly but steadily. The rat hears, therefore, before these cells have reached their full size.

The largest cells in the vestibular ganglion are precocious and remarkably developed, even at birth. They cease their rapid growth at about fifteen days of age, but increase very slightly though steadily throughout life.


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