miles is carried with it into the mouth of the
Fallopian tube.



609



In ova which are not quite ripe, these nu-
cleated cells are round, but during the oes-
trus, in the riper ova, the cells become elon-
gated and fusiform, having their pointed ends
attached to the zona pellucida or bounding
membrane of the ovum. They present a
glassy swollen aspect, by which the fully ripe

Fig. 410.




Ripe ovum from the ovary. Guinea-pig.
Bischoff.)



(After



ova acquire an appearance of being sur-
rounded by rays. This change occurs in
most mammalia, as the dog, rabbit, sheep,
rat, roe, and kangaroo. It is characteristic
of the mature ova, and may be regarded as a
certain sign of their ripeness.

Corresponding with this external alteration
in the appearance of the ovum, are certain
internal changes, of which the chief is the
disappearance of the germinal vesicle. This
indeed seems to be an almost constant phe-
nomenon throughout the mammalia, though,
as to the precise mode, or even time, of dis-
appearance of this important constituent of
the ovum, observers are by no means agreed.
By Barry it was considered, after close ob-
servation, that the vesicle was not dissolved
nor ruptured, as many now suppose, but that
it became lost to observation by retiring to
the centre of the ovum, where it was changed
in character by an internal process of cell de-
velopment.

These changes, external and internal, are
the precursors of impregnation, and charac-
terise the ovum shortly prior to and at the
period of its quitting the ovary.

Arrived within the Fallopian tube, the first
alteration which the ovum experiences is the
stripping off of the ray-like appendage of nu-
cleated cells with which it quitted the ovary.
This change results apparently from a burst-
ing and diffluence of these cells, now no
longer capable of serving any useful purpose ;
Sttpp.



for the conjecture that they might furnish
materials for the construction of the chorion
has not been supported by any direct obser-
vations. On the contrary, numerous obser-
vations of Bischoff show that this process of
freeing the ovum from its surrounding layer
of cells, takes place very soon after its en-
trance within the tube, and generally in the
upper third.

Fig. 411.




The ovum on first arriving in the Fallopian tube.
The ray-like appendages are nearly stripped off.
(After Bischoff.)

a, zona pellucida ; b, granular bodies between the
zona pellucida and yelk. Rabbit.

And now, if the coitus does not obtain,
and no contact of the generative elements
occurs, the ovum perishes ; observations at
least relative to its further fate are wanting.
But should the ovum have become fertilised,
then a noticeable series of changes takes
place, of which the following are the most
important.

The zona pellucida, or transparent bound-
ing membrane of the ovum, having been freed
of its external granular investment, the entire
ovum presents the condition represented in
figure 412. Deprived now of all encum-
brance, the surface of the ovum is in a
condition eminently favourable for the pas-
sage through it of the spermatozoa, which
penetrate readily that soft outer coat, and
thus gain admission to the yelk.

The fact of the penetration of the outer
coat of the ovum by the spermatozoa, which
has been so often asserted and denied, may
now, after much controversy, be considered
as established. In the mammalian ovum,
this passage may take place apparently
through any portion of the outer coat, j ust
as it does in the ova of amphibia, and not
through a special pore or microphyle, such
as exists in the ova of osseous fishes.

Following this act of penetration occurs
a change which apparetly affords the first
distinct evidence that the power of the sper-
matozoa has been efficiently exerted upon
the ovum. The yelk, which had previously
completely filled the zona, is observed to
have become contracted, so that an inter-
space is left between it and the zona, termed
by Newport, who has carefully watched its
formation in the ova of amphibia, the " re-
spiratory chamber." Such a retiring of the
yelk, so as to leave an interspace between

R K



610



UTERUS AND ITS APPENDAGES.



the latter and the zona pellucida, which in-
terspace is filled by a transparent fluid, has
been noticed in many mammalia, as the
Guinea-pig, rabbit, &c.

Fig. 412.




The ovum a little more advanced in the tube. (After
Bischoff.)

The surface is perfectly smooth. Spermatozoa
have penetrated the zona pellucida. The respira-
tory chamber is formed between the latter and the
yelk. The rotation of the yelk has commenced, as
indicated by the arrows. The granular bodies ap-
pear preparatory to the segmentation of the yelk.
Several of these stages are seen commencing in the
preceding figure. Rabbit,

This change is preliminary to another oc-
currence, which has been observed in the
ova of many animals, both vertebrate and
invertebrate, viz. the rotation of the yelk
within the interspace just described ; a ro-
tation which is effected by the aid of cilia
clothing the surface of the yelk.

About this time may be observed one, or
perhaps two, small granular bodies, whose
formation has given rise to many and varied
speculations regarding their signification and
use. They occupy a portion of the space
between the yelk and zona pellucida, and
appear to be common to the mammalian
ovum and that of other classes. The most
probable supposition regarding their use con-
nects them with the division or cleavage of
the yelk which follows their appearance.

Whatever doubts may be entertained as to
the dependence of the phenomena already
described upon a preceding act of impregna-
tion, all question is set at rest at this point,
by the direct experiments of Newport, who

Fig. 413.




ascertained beyond doubt, that segmentation
of the yelk is the result of impregnation alone,
and that it never takes place in the unim-
pregnated ovum.

This segmentation of the yelk consists in
a spontaneous cleavage of that body, at first
into two, and then into four, equal parts ; the
process of division continuing in geometric
progression until the whole is broken up into
a mass of finely nucleated particles, between
which the original sperm-force is probably
equally divided.

Segmentation of the yelk of the mamma-
lian ovum has never been observed in its
commencing stages anywhere but in the tube.
The extent to which it proceeds beibre the
ovum quits the oviduct to enter the uterus
appears to vary in different species. Bischoff
never saw more than four yelk-divisions in
the ovum of the Guinea-pig by the time that

Fig. 414.




The ovum from the lower or uterine end of the
Fallopian tube. {After Bischoff.)

The yelk exhibits four divisions. Babbit.

it had reached the lower portion of the tube ;
and it is probable that a further division into
eight parts occurs in the extreme end of the
duct, since, in the next condition of the ova
found in the uterus, the yelk exhibited 12
16 divisions.

The only remaining change in the condition
of the ovum during its residence in the ovi-

Fig. 415.




The ovum still more advanced in the tube. {After The addition of a layer of albumen in the lower por-
Bischoff.) tion of the tube (observed only in the rabbit.')

(After Bischoff.)



The first stage in the segmentation of the yelk
has taken place. Rabbit.



The yelk exhibits eight divisions.



FALLOPIAN TUBE OR OVIDUCT (FUNCTIONS).



duct, which it is necessary here to notice, is
the addition, sometimes, of a thick layer of
albumen around the zona pellucida, which is
formed upon it in the middle and lower por-
tions of the tube. BuUhis is certainly not a
constant, and apparently not even a common
occurrence. It occurs in the rabbit, but not
in the bitch, Guinea-pig, or roe.

These are the principal and more obvious
changes which the ovum experiences in its
passage down the Fallopian tube until it
enters the uterus. So regular is the order
with which they succeed each other that
particular portions of the tube may be as-
signed as the seat of each occurrence*. Thus
the first, or upper third of the oviduct is
appropriated to the reception of the ovum,
which, soon after quitting the ovary, is here
deprived of its adventitious covering of nu-
cleated cells, and is thus prepared for the
full operation of the spermatozoa, whose
active movements in this part of the tube
have been frequently noticed. Here also
spermatozoa have been frequently seen upon,
and even within, the ova ; and here the first
changes characteristic of the commencing
operations of the sperm force, such as the
formation of the respiratory chamber, and
rotation of the yelk, may be noticed. In the
middle of the tube the ova commonly exhibit
still more decided evidences of impregnation.
The cleavage of the yelk has already com-
menced, and one or more granular bodies
occupy the space between it and the zona.
The ova found in the lower third, except
those which may be destined to perish, al-
ways show unmistakable signs of impregna-
tion, of which the segmentation of the yelk,
now advanced to the production of 12 16
divisions, is the most expressive.

If the views of Bischoff be correct, it is in
the upper third, or at farthest in the middle
of the tube, that impregnation must occur,
unless indeed it takes place at the ovary.
For in the lower end of the tube the more
definite developmental changes of the ovum
occur, or otherwise the ovum perishes. In
the dog and Guinea-pig, by the time the ovum
has reached this spot, the oestrus is past, and
the animal will no longer permit the coitus.*

Connected apparently with some of the
foregoing steps in the process of generation,
though it does not appear precisely with
which, is a phenomenon described by Bis-
choff as occurring in the Guinea-pig. Several

* Pouchet (L'Ovulation Spontanee) places the
seat of impregnation lower down in the oviduct.
He asserts that it is only about the middle of the
tube, or more particularly in its lower portion, and
even in the cavity of the uterus itself, that the
material contact of the ova with the spermatozoa
can occur. And he regards the passage of the
semen as far as the extremity of the tube, and its
arrival at the ovary, as an " excessively rare ano-
malj-." But these statements are based upon ex-
aminations directed only to the detection of the
presence of spermatozoa in the oviduct, and are not
connected with microscopic observations of those
developmental changes in the ovum, which are in-
disputably the results of impregnation, and of which
an account has been given in the text.



611

times Bischoff had the good fortune to ob-
serve with a lens, and also under the micro-
scope, a peristaltic action in the walls of the
oviduct, by which the contained ova, visible
through them, were moved backwards and for-
wards. The ova appeared to be surrounded
by a transparent fluid, in which they floated.

Now, such an observation is interesting,
when viewed in connexion with two circum-
stances, specially observed and proved by
Newport, namely, that in the artificial im-
pregnation of the ova of amphibia, although
the process of impregnation is commenced at
the instant of contact of the spermatozoa with
the ova, yet a certain duration of contact is
essential to its completion. And further, that
although an exceedingly minute quantity of
spermatozoa suffices to impregnate the ovum,
yet impregnation takes place more tardily
when the number is extremely limited than
when the number is in full abundance ; while
when the quantity is reduced below a certain
amount, or the duration of contact is limited,
then the phenomenon is incomplete, and
partial impregnation, evidenced by imperfect
segmentation of the yelk, and arrest of the
further stages of development, is the in-
evitable result.

Since, then, it cannot be supposed that a
less perfect or complete contact of the ova
with the spermatozoa is needful to their im-
pregnation in the higher than in the lower
vertebrata, there seems to be good ground
for conjecturing that this peculiar peristaltic
movement in the walls of the Fallopian tube,
which has been noticed also by other ob-
servers, may have for one of its objects the
more perfect commingling of the two gene-
rative elements, the spermatozoa and the ova,
which, proceeding as they do in opposite di-
rections, and encountering each other in some
portion of the canal, would thus be carried
backwards and forwards, and thus a certain
permanence of contact, such as Newport has
shown to be necessary in the amphibia, would
be insured to them. And this supposition
may be further strengthened by the reflection
that while an onward movement in either di-
rection would serve for the conveyance of
each element singly along the tube, a back-
ward and forward motion alternating could
only retard either or both processes, and that
there could be only one apparent advantage
in such retardation, namely, the retention of
both elements for a longer or shorter time in
permanence of contact.

To sum up the offices of the Fallopian
tube, the following may be said to have been
with certainty ascertained to belong to that
division of the generative organs : To re-
ceive the spermatic fluid from the uterus
and convey it upwards through the entire
canal, and as far sometimes as the ovary ; v
To receive contrariwise the unimpregnated
ova, as they are discharged from the ovary,
by means of its expanded open mouth, which
in these cases, where the entire ovary cannot,
be grasped, is guided, by a process hitherto
unexplained, to select and apply itself to that
R R 2



612



UTERUS AND ITS APPENDAGES.



particular spot from which the ripe ovum is
about to be expelled ; to convey the ovum
in a direction opposite to the course of the
fertilising fluid, so as to ensure the meeting
and commingling of the generative elements,
an event to which the limited calibre joined to
the peristaltic action of the oviduct probably
in a great degree contributes ; to afford pro-
tection to the ovum during that brief sojourn
in which the first effects of fertilisation are
manifested upon its constituent parts ; to
aid probably in certain changes which are
operated upon the surface of the ovum, con-
sisting first, in all cases apparently, in a strip-
ping off of the adventitious covering with
which the ovum is invested on entering the
tube, and secondly, in some instances, in
the addition of certain materials which in-
crease slightly the bulk of the ovum ; and
lastly, in transmitting onwards the ovum, so
altered and prepared for more complete de-
velopment, to the cavity of the uterus, or in
conveying away those which, for want of
impregnation, are destined to perish.

In reference to these conclusions regarding
the offices of the Fallopian tube, which the
present state of physiology appears to war-
rant, the question here naturally arises, how
far they are applicable to the female of man,
or to what extent her case may be viewed
as exceptional on account of certain differ-
ences in her organisation and habitudes.

One of the most observable of these dif-
ferences is the absence of that marked dis-
tinction of periods alternating with each other,
such as are shown in a greater or less degree
in the females of most mammalia in regard
to the activity of the sexual functions.

That these alternating periods of desire
and aversion to the coitus are strictly sig-
nificant of corresponding temporary states of
physical capacity and incapacity for concep-
tion, is placed beyond doubt, by the results
of examination of the internal organs and
their contents at these respective periods.

In those animals in which the oestrus re-
turns at short intervals, the male generally
remains potent at all times. The temporary
incapacity is on the side of the female, and
occurs in the intervals between the successive
acts of ripening and discharge of the ova from
the ovary, together with their passage down
the tube. It has been shown that during
these events only will she receive the male,
and therefore, on that account also, is con-
ception then only possible.

This circumstance is rendered more striking
in animals in whom this interval is longest,
as in the roe-deer, where the oestrus returns
only once annually, and in whom the capacity
for procreation is limited to a few weeks, for
the reason stated by Bischoff, that then the
ovary contains ripe ova and the testes ripe
semen, and at no other time.

But in the human female, whatever views
may be entertained regarding the connexion
of a separate act of ovulation with each
menstrual period, it is certain that here a
marked oestrus is wanting, and that although



the capacity for impregnation is apparently
greatest about the times of menstruation,
yet, notwithstanding the assertions of those
who maintain that there is a perpetual recur-
rence of temporary incapacity for procrea-
tion, there is no period at which the healthy
human female can be shown to be positively
incapable of conception during any part of
menstrual life.

It may, however, be asked whether the oc-
casional occurrence of impregnation during
an intermenstrual period, at a date more
distant than usual from the last menstrual
act can be explained consistently with a strict
interpretation of the law that menstruation
and ovulation are contemporaneous acts.

This appears to be reconcilable with the
circumstance that although these acts, so far
as observation has yet gone, are very fre-
quently and perhaps usually coincident, yet
exceptionally an ovum may be emitted during
an intermenstrual period, the ripening and
not the time or the act of emission of the
ovum being probably the essential feature, or
that the ovum, supposing it to have been
emitted from the ovary at the time of men-
struation, may possibly remain in the tube
susceptible of impregnation longer in the
human female than in the mammalia gener-
ally, or may even be impregnated after reach-
ing the uterus. *

That the Fallopian tube in the human
subject is, occasionally at least, the seat of
impregnation, is demonstrated by the occur-
rence of the tubal form of extra-uterine ges-
tation ; while the numerous examples already
quoted of other mammalia render it highly
probable, by analogical reasoning, that this is
the normal seat of that function in man.

That the first encounter of the generative
elements may also take place either in the
uterus or upon or even within the ovary, is
plainly possible. That it occurs sometimes at
or near the ovary is evidenced by the varieties
of extra-uterine gestation termed ovarian and
ovario-tubal. It is even possible that, in
some of these, insemination may have been
so coincident with the spontaneous opening
of the Graafian follicle, that the spermatozoa,
penetrating further than usual, may have
reached the ovary at that precise moment
when a passage had been prepared for the
ovum, and some may have actually passed
into the follicle and have impregnated the
ovum there. No argument certainly can be
opposed to this on the ground of physical
impossibility -j* ; while, on the other hand, it
is also conceivable that impregnation may be
delayed until after the ovum has entered the
uterus, as in the case just suggested of a
fertilising coitus occurring later than usual
after the menstrual period ; but I am not
aware of any good anatomical or physiological
reason for regarding the uterus, as by pre-

* These points are more fnlly considered under
the head <; Menstruation," p. GG8.

f See the argument regarding the anatomical
evidence for this form of gestation at p. 586.



FALLOPIAN TUBE OR OVIDUCT (DEVELOPMENT).



fercnce, the seat of normal impregnation j
while such a view is opposed to those nu-
merous observations upon the mammalian
ovum generally, which show, that before the
ovum quits the oviduct, the developmental
changes in it are already advanced many
stages, while, by the time that it arrives at
the uterus, the opportunity for impregnation
has already passed away for that occasion.

DEVELOPMENT OF THE FALLOPIAN TUBE.

Whatever difference of opinion may exist
regarding the origin of the excretory duct of
the male generative gland, there appears to be
no doubt, that in birds at least the correspond-
ing part in the female has its commencement
in a structure which, as soon as it can be
recognised as a distinct tube, is altogether
separate from the Wolffian body. This is
called after its first observer, tne duct of
Mil Her* (Jig. 400. g).

The mode of origin of this duct has been
already partly described in the account which
has been given of the formation of the Paro-
varium (p. 594.). Its development may be
most conveniently traced in birds, where it
can be easily shown that the oviduct is not a
metamorphosis of the excretory duct of the
Wolffian body, but may be distinguished lying
near it, in the form of a tolerably thick tube ;
which at first ends in a closed extremity, but
afterwards exhibits a wide orifice. It runs
along the outer side of the W T olffian body,
while its infundibulum, which is soon distin-
guishable, extends beyond and is entirely se-
parate from that body.

The oviducts appear from the first in the
form of white cylinders on both sides. They
do not grow from below upwards, but are
formed in their entire length from the com-
mencement ; nor are they constructed out of
a membranous lamina, rolled together, as
Meckel supposed; but are in the beginning
solid, and become gradually hollowed out into
a tube. In this way also is formed the infun-
dibular opening of the tube into the abdomi-
nal cavity.

Two oviducts exist, originally in all birds,
but as in this class the right ovary shrinks
and disappears, so the right oviduct becomes
lost, by gradually contracting and shortening
from above downwards, f-

In mammals, before the distinction of sex
becomes apparent internally, there is seen,
running along the W T olffian body of each side
in every embryo, a duct, which, according to
Miiller, may represent either a vas deferens,
or an oviduct. These ducts lie upon opposite
sides of the germ glands, which may become
afterwards testis or ovary.

Soon afterwards the internal organs begin
to exhibit a distinction of sex. This is indi-

* See Miiller's Bildungsgeschichte der genita-
lien. Diisseldorf, 1830.

f Prof. Quekett has pointed out to me, in the col-
lection of the Royal College of Surgeons, a remark-
able preparation by Mr. Tegetmeir, in which the
tight oviduct is developed in the common fowl.



613

cated in the future male by the duct, which
runs along the outer side of the Wolffian
body, sending off a white granular projection,
extending towards the testis, which is met by
a similar projection, given off by the upper
end of the testis, and these two by their
union form the rudiments of the epididymis.
So that in the male mammal a new connexion
is established between the duct, which after-
wards becomes vas deferens, and the testis,
without any agency from the Wolffian body,
but through the development of new material.

In the female these projections are wanting,
both from the excretory duct and from the
ovary. The latter remains attached only to
the Wolffian body by a simple fold. The up-
per end of the duct, which runs over the
Wolffian body, projects somewhat beyond that
body inferiorly, and terminates here in a glo-
bular swelling, in which an aperture is formed
at a later period.

As the Wolffian body becomes atrophied
the portion of the duct which takes its course
over it, and which was previously straight,
begins to be tortuous in the male, while in the
female it remains straight, but becomes wider.
Out of corresponding portions of the duct
are formed, in the male, the head of the epi-
didymis, and in the female the infundibular
end of the tube, while the inferior free por-
tion of the duct, after it has quitted the
Wolffian body becomes converted, in the male,
into the vas deferens, becoming at the same
time more and more elongated ; but in the
female the corresponding portion of the duct
is transformed into the inferior division of
the lube, or into the cornu of the uterus.*

In this stage of its development the inci-
pient Fallopian tube is only beginning to be
recognisable. It circumscribes the diminish-
ing Wolffian body on its outer side in the
form of a bow. Above the superior opening
extends beyond that body, while below the
short free portion becomes conjoined with that
of the opposite side to form a single tube.