EXERCISE THE SIXTY-NINTH.
Of what takes place in the uterus of the doe during the month of November.
Taught by the experience of many years I can state truly that it is from the 12th to the 14th of November that I first discover anything which belongs to the future offspring in the uterus of the hind.
I remember, indeed, that in the year of grace 1633, the signs of conception, or the commencements of the embryos, made their appearance somewhat earlier; because the weather was then cloudy and wet. In does, too, which have rutted six or seven days sooner than hinds, I have always discovered something of the future fœtus about the 8th or 9th of November. What this is and how it is begun I shall proceed to state.
A little before anything is perceptible, the substance of the uterus or its horns appears less than it was before the animals began to rut, the white caruncles are more flaccid, as I have said, and the protuberances of the internal coat subside somewhat, and are corrugated and look moist. For about the date above mentioned certain mucous filaments like spiders’ webs are observed drawn from the extremities, or superior angles of the cornua through the middle of either, and also through the body of the uterus. These filaments becoming conjoined present themselves as a membranous and gelatinous tunic or empty sac. Even as the plexus choroides is extended through the ventricles of the brain, is this oblong sac produced through the whole of either horn and the intervening cavity of the uterus, insinuating itself between the wrinkles of the flabby internal tunic, and sending delicate fibres among the aforementioned rounded protuberances, being nearly in the same manner as the pin mater dips between the convolutions of the brain.
Within a day or two this sac becomes filled with a clear, watery, sluggish albuminous matter, and now presents itself as a long-shaped pudding full of fluid. It adheres by its external glutinous matter to the containing walls of the uterus, but so that it is still easily separated from these; for if it be taken hold of cautiously in the strait of the uterus, where it is constricted in its course, it can be drawn entire out of either horn.
The conception arrived at this stage removed entire, presents itself with the figure of a wallet or double pudding; externally, it is covered with a purulent-looking matter; internally, it is smooth, and contains in its cavity a viscid fluid not unlike the thinner white of egg.
This is the conception of the hind and doe in its first stage. And since it has now the nature and state of an egg, and the definition given by Aristotle[338] of an egg is applicable to it, namely: “A body from one part of which an animal is produced, the remainder serving as nourishment to that which is engendered;” and farther, as it is the primordium of the future fœtus, it is therefore called the ovum, or egg of the animal, in conformity with that passage of the philosopher where he says:[339] “Those animals which engender internally, have a certain oviform body produced after the first conception. For a humour is included within a delicate membrane, such as that which you find under the shell in the egg of the hen; wherefore the blightings of conceptions that are apt to take place about this period are called fluxes.” This conception, therefore, as we have already said of the egg, is the true sperma or seed, comprising the virtue of both sexes in itself, and is analogous to the seed of the vegetable. So that Aristotle, describing the first conception of women, says,[340] that it is “covered with a membrane like an egg from which the shell has been removed;” such as Hippocrates describes as having been passed by the female pipe-player. And I have myself frequently seen such ova, of the size of pigeons’ eggs, and containing no fœtus, discharged by women about the second month after conception; when the ovum was of the size of a pheasant’s or hen’s egg, the embryo could be made out, the size of the little finger nail, floating within it. But the membrane surrounding the conception has not yet acquired any annexed placenta; neither is it connected with the uterus; there is only at its upper and blunter part a kind of delicate mossy or woolly covering which stands for the rudiments of the future placenta. The inner aspect is smooth and polished, and covered with numerous ramifications of the umbilical vessels. In the third month this ovum exceeds a goose’s egg in size, and includes a perfect embryo of the length of two fingers’ breadths. In the fourth month it is larger than an ostrich’s egg. All these things I have noted in the numerous careful dissections of aborted ova which I have made.
In the way above indicated do the hind and doe, affected by a kind of contagion, finally conceive and produce primordia, of the nature of eggs, or the seeds of plants, or the fruit of trees, although for a whole month and more they had exhibited nothing in the uterus, the conception being perfected about the 18th, at furthest, the 21st of November, and having its seat now in the right, now in the left horn, occasionally in both at once. The ovum at this time is full of a colliquate matter, transparent, crystalline, similar to that fluid which in the hen’s egg we have called the colliquament or eye, of far greater purity than that fluid in which the embryo by and by floats, and contained within a proper tunic of extreme tenuity, and orbicular in form. In the middle of the ovum, vascular ramifications and the punctum saliens—the first or rudimentary particle of the fœtus—and nothing else, are clearly to be perceived. This is the first genital part, which, once constituted, is not only already possessed by the vegetative, but also by the motive soul; and from this are all the other parts of the fœtus, each in its order, generated, fashioned, disposed, and endowed with life, almost in the same manner as we have described the chick to be produced from the colliquament of the egg.
Both of the humours mentioned are present in the conceptions of all viviparous animals, and are regarded by many as the excrements of the fœtus,—one the urine, the other the sweat, although neither of them has any unpleasant taste, and they are always and at all periods present in conceptions, even before a particle of the fœtus has been produced.
Of the membranes investing the two fluids, of which there are only two, the outer is called the chorion, the inner the amnion. The chorion includes the whole conception, and extends into either cornu; the amnion swimming in the midst of the liquid of the former, is found in one of the horns only, except in the cases where there is a twin conception, when there is an amnion present in each of them; just as in a twin-fraught egg there are two colliquaments. Where there are two fœtuses consequently, both are contained in one common conception, in one egg, as it were, with its two separate collections of crystalline fluid included. If you incise the external membrane at any point, the more turbid fluid which it contains immediately escapes from either horn of the uterus; but the crystalline liquid in the interior of the amnion does not escape at the same time unless the membrane have been simultaneously implicated.
The vein which is first discerned in the crystalline fluid within the amnion takes its rise from the punctum saliens, and assumes the nature and duty of an umbilical vessel; increasing by degrees it expands into various ramifications distributed through the colliquament, so that it seems certain that the nourishment is in the first instance derived from the colliquament alone in which the fœtus swims.
I have exhibited this point to his serene highness the king, still palpitating in the uterus laid open; it was extremely minute indeed, and without the advantage of the sun’s light falling upon it from the side, its tremulous motions were not to be perceived.
When the ovum with the colliquament entire was placed in a silver or pewter basin filled with tepid water, the punctum saliens became beautifully distinct to the spectators. In the course of the next ensuing days, a mucilage or jelly, like a tiny worm, and having the shape of a maggot, is found to be added; this is the rudiment of the future body. It is divided into two parts, one of which is the head, the other the trunk, precisely in the same way as we have already seen it in the generation of the chick in ovo. The spine, like a keel, is somewhat bent; the head is indifferently made up of three small vesicles or globules, and swimming in transparent water grows amain, and by degrees assumes its proper shape. There is only this to be observed, that the eye in embryos of oviparous animals is much larger and more conspicuous than that of viviparous animals.
After the 26th of November the fœtus is seen with its body nearly perfect, in one case in the right in another in the left horn of the uterus; in twin cases in both horns.
At this time, too, the male embryo is readily distinguishable from the female by means of the organs of generation. These parts are also very conspicuous in the human embryo, and make their appearance at the same time as the trachea.
Males and females are met with indifferently in the right and left horn of the uterus. I have, however, more frequently found females in the right, males in the left horn; and I have made the same observation in does that carried twins, as well as in the sheep. It is certain, therefore, that the right or left side has no appropriate virtue in conferring sex; neither is the uterus, nor yet the mother herself, the fashioner or framer of the fœtus, any more than the hen is of the pullet in the egg which she incubates. In the same way as the pullet is formed and fashioned in the egg by an internal and inherent agent, is the fœtal form produced from the uterine ovum of the hind and doe.
It is indeed matter of astonishment to find a fœtus formed and perfected within the amnion in so short a space of time after the first appearance of the blood and punctum saliens. On or about the 19th or 20th day of November this punctum first becomes visible; on the 21st the shapeless vermiculus or maggot that is to form the body of the future animal is perceived; and in the course of from six to seven days afterwards a fœtus so perfect in all its parts is seen, that a male can be distinguished from a female by the organs of generation, and the feet are formed, the hooves being cleft, the whole having a mucous consistency and a pale yellowish colour.
The substance of the uterus begins to be extenuated immediately after the appearance of the embryo; contrary to what takes place in the human female, whose uterus grows every day thicker and fleshier with the advancing growth of the fœtus. In the hind and doe, on the other hand, the more the embryo augments the more do the cornua of the uterus assimilate themselves to the intestines; that horn in particular in which the fœtus is contained looks like a bag or pouch, and exceeds the opposite one in dimensions.
The ovum or conception, thus far advanced, and with its included fœtus perfectly distinct, has still contracted no adhesions to its mother’s sides: the whole can most readily be withdrawn from the uterus, as I have ascertained with an ovum which contained a fœtus nearly the length of the thumb. It is manifest, therefore, that the fœtus up to this period has been nourished by the albumen alone that is contained within the conception; in the same way as we have ascertained the process to go on within the hen’s egg. The mouths of the umbilical veins are lost and obliterated between the albumen and neighbouring humours of the conception and their containing membranes; but nowhere is there as yet any connexion with the uterus, although by these veins alone is nourishment supplied to the embryo. And as in the egg the ramifications of the veins are first sent to the colliquament, (in the same way as the roots of trees penetrate the ground,) and afterwards take their course to the external tunic called the chorion, whereon, for the sake of the nourishment, they are dispersed in an infinity of ramifications through the albuminous fluid contained within the outer membrane, so have I observed veins in the chorion of a human abortion; and Aristotle[341] also states “that membrane to be crowded with veins.”
If the fœtus be single its umbilical vessels are distributed to both horns, and a few twigs are also sent to the intervening body of the uterus; but if the conception be double, one in either horn, each sends its umbilical vessels to its own horn alone; the embryo in the right horn deriving nourishment from the right part of the conception, that in the left from the left portion of the same. In other respects the twin-conception here is precisely similar to the twin-conception of the egg.
Towards the end of November, then, all the parts are clearly and distinctly to be distinguished, and the fœtus is now of the size of a large bean or nutmeg; its occiput is prominent, as in the chick, but its eyes are smaller; the mouth extends from ear to ear, the cheeks and lips, as consisting of membranous parts, being perfected at a very late period. In the fœtuses of all animals, indeed, that of man inclusive, the oral aperture without lips or cheeks is seen stretching from ear to ear; and this is the reason, unless I much mistake, why so many are born with the upper lip divided as it is in the hare and camel, whence the common name of hare-lip for the deformity. In the development of the human fœtus the upper lip only coalesces in the middle line at a very late period.
I have frequently put a fœtus the size of a large bean, swimming in its extremely pure nutritive fluid within the transparent amnion, into a silver basin filled with the clearest water, and have noted these particulars as most worthy of observation:—The brain of somewhat greater consistency than white of egg, like milk moderately coagulated, and of an irregular shape, and without any covering of skull, is contained within a general investing membrane. The cerebellum projects in a peak, as in the chick. The conical mass of the heart is of a white colour, and all the other viscera, the liver inclusive, are white and spermatic-looking. The trunk of the umbilical veins arises from the heart, and passing the convexity of the liver, perforates the trunk of the vena portæ, whence, advancing a little and subdividing into a great number of branches, it is distributed to the colliquament and tunica choroidea in innumerable fine filaments. The sides of the body ascend on either hand from the spine, so that the thorax presents itself in the guise of a boat or small vessel, up to the period at which the heart and lungs are included within its area, precisely and in all respects as we have seen it in the development of the chick. The heart, intestines, and other viscera, are very conspicuous, and present themselves as appendages of the body, until the thorax and abdomen being drawn around them, and the roof, as it were, put on the building, they are concealed within the compages of these cavities. At this time the sides both of the thorax and abdomen are white, gelatinous, and apparently identical in structure, save that a number of slender white lines are perceived in the walls of the thorax, as indications of the future ribs, whereby a distinction is here made between the bony and fleshy compages of the cavity.
I have also occasionally observed in conceptions of the sheep, which were sometimes twin, sometimes single, of corresponding age and about a finger’s breadth in length, that the form of the embryo resembled a small lizard of the size of a wasp or caterpillar; the spine being curved into a circle, and the head almost in contact with the tail. In the double conceptions both were of the same size, as if produced at once and simultaneously; each floated distinctly within the fluid of its own amnion; but although one lay in the right, the other in the left horn of the uterus, they were still both included in the same double sac or wallet, both belonged to the same ovum, and were surrounded by the same common external fluid. The mouth was large, but the eyes were mere points, so that they could scarcely be seen, very different, therefore, from what occurs among birds. The viscera in these embryos were also pendulous without the body,—not yet inclosed within the appropriate cavities. The outer membrane or chorion adhered in no way to the uterus, so that the entire conception was readily removed. Within the substance of the chorion innumerable branches of the umbilical vessels were conspicuous, but having no connexion whatsoever with the walls of the uterus; a circumstance to which allusion has already been made in the case of the deer; the distribution was in fact very much as we have found it on the external tunic of the hen’s egg. There were but two humours, and the same number of containing tunics, of which the chorion extending through both cornua, and full of a more turbid fluid, gave general configuration to the ovum or conception. The tunica amnios again is almost invisible, like the tunica arachnoides of the eye, and embraces the crystalline humour in which the embryo floats.
The fluid of the amnion was, in proportion, but a hundredth, or shall I say a thousandth, to that of the chorion; although the crystalline humour of the amnion was still in such quantity that no one could reasonably imagine it to be the sweat of the very small embryo that floated within it. It was, further, extremely limpid, and seemed to be without anything like bad taste or smell. It was, as we have already observed of the deer, in all respects like watery milk, and had none of the obnoxious qualities of an excrement. I add, that if this fluid were of an excrementitious nature it ought to increase in quantity with the growth of the fœtus. But I have found precisely the opposite of this to obtain in the conception of the ewe, so that shortly before she lambs there is scarce a drop of the fluid in question remaining. I am, therefore, rather inclined to regard it as aliment than as excrement.
The internal tunic of the uterus of the ewe is covered with caruncles innumerable, as the heavens are with stars. These are not unlike crabs’ eyes, and I have called them by this name; but they are smaller, like pendulous warts, glandular and white, sticking within the coats of the uterus, and somewhat excavated towards the conception; otherwise than in the deer, consequently, in which the caruncles corresponding to these rather project towards the embryo. These caruncles are gorged with blood, and their inner surface, where they regard the conception, is perceived to be beset with black sanguineous points. The umbilical vessels of the embryo were not yet connected with these caruncles, nor did the conception itself adhere to the uterus.
I find nothing of an allantois, of which something has been said as a tunic distinct from the chorion, in the conception of the ewe. At a later period, indeed, when the embryo is larger, when the ovum or conception has contracted adhesions with the uterus, and the umbilical vessels have penetrated the caruncles, the chorion extends further, and at its extremities on either side, and as it were in a couple of appendices, there is a certain fluid of a yellow colour, which you might call excrementitious, kept separate and distinct.
The human conception scarcely differs in any respect from an egg during the first months of pregnancy. I have observed a clear fluid, like the more liquid white of an egg, to be included within an extremely delicate membrane. At this time the placenta had not yet appeared, and the entire conception was of the size of a pigeon’s, or perhaps a pheasant’s egg. The embryo itself, of the length of the little finger nail, and having the form of a small frog, was conspicuous enough. The body was broad, the oral aperture widely cleft, the legs and arms like the stalks of flowers just risen above the ground, the occiput prominent, or rather forming a vesicle appended to the rest of the head, such as we have described the rudiments of the future cerebellum in the chick.
In another human conception of about the fiftieth day, the ovum was as large as a hen’s or a turkey’s egg. The embryo was as long as a large bean, the head of very large relative dimensions, and dominated by the cerebellum as by a kind of crest. The brain itself was of the consistence of curdled milk. Instead of a cranium there was a coriaceous membrane, in some places cartilaginous, and divided down the forehead to the roots of the nostrils; the face looked like the muzzle of a dog. There were no external ears, nor any nose, yet could the rudiments of the trachea passing down to the lungs, and those of the penis, be detected. The two auricles of the heart presented themselves like eyes, of a black colour.
In the body of a woman who died of fever I found an hermaphrodite embryo nearly of the same size. The pudendum was like that of the rabbit, the labia standing for prepuce, the nymphæ for glans. In the upper part the root of the penis was also apparent, and on either side for the testicle there was the lax skin of the scrotum. The uterus was extremely diminutive, and in figure like that of the ewe or mole, with two horns. And as the prostate glands are situated near the penis of the boy, so were the testicles (ovaries) of visible dimensions, seen adjacent to these cornua. Externally considered, the sex seemed that of the male; internally, however, it was rather that of the female. The uterus of the mother was of great size, having the urinary bladder connected with it as an appendage. In the embryo, on the contrary, the bladder was large with the uterus of very small dimensions attached to it.
All the human ova that have been described above were, like those of the ewe, shaggy externally, and besmeared with a kind of gelatine, or glutinous matter. At this epoch, too, there was neither any placenta apparent, nor any visible connexion with the uterus; neither was there any implantation into the substance of the uterus of the umbilical vessels scattered over the surface of the conception itself.
As in the deer, so in the sheep, goat, and other bisulcated animals, do we find more than one fœtus in the same conception, just as in twin-fraught eggs we find two chicks surrounded by the same albumen. But in the dog, rabbit, hog, and other viviparous animals that produce a considerable number at a litter, the thing is otherwise. In these each fœtus has two humours, these being severally surrounded with their proper membranes.
In the bitch there are a number of knots or constrictions along the whole course of either cornu of the uterus, between each of which the appropriate humours and a single embryo are contained. In the hare and rabbit we observe a number of balls, like the eggs of serpents, so that the horns of the uterus look like a pair of bracelets composed of so many amber beads strung upon a thread. The conception of the hare bears a strong resemblance to an acorn, the placenta embracing the embryo like a cup, and the humours inclosed in their membranes depending like the gland or nut.