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.
EXERCISE THE SEVENTIETH.
Of the conception of the deer in the course of the month of December.