the conception or ovum ; nor has the ovum in these animals at any time a connexion with the uterus.
From all of what precedes it is manifest that in both the classes of viviparous animals alluded to, those, namely, that are provided with carunculae or cotyledons, and those that want them, and perhaps in viviparous animals generally, the foetus in utero is not nourished otherwise than the chick in ovo ; the nutritive matter, the albumen, being of the same identical kind in all. As in the egg the terminations of the umbilical vessels are in the white and yelk, so in the hind and doe, and other animals furnished with uterine cotyledons like them, the final distributions of the umbilical vessels are sent to the humours that are included within the conception or ovum, and to the albumen that is stored in the cotyledons, or cup-like cavities of the carunculae, where they open and end. And this is further obvious from the fact of the extremities of the umbilical vessels, when they are drawn out of the afore-mentioned mucor, looking completely white ; a certain proof that they absorb this mu- cilage liquefied only, and not blood. The same arrangement may very readily be observed to obtain in the egg.
The human placenta is rendered uneven on its convex surface, and where it adheres to the uterus, by a number of tuberous projections, and it seems indeed to adhere to the uterus by means of these ; it is not consequently attached at every point, but at those places only where the vessels pierce it in search of nourishment, and at those where, in consequence of this ar- rangement, an appearance as if of vessels broken short off is perceived. But whether the extremities of these vessels suck up blood from the uterus, or rather a certain concocted matter of the nature of albumen, as I have described the thing in the hind and doe, I have not yet ascertained.
Finally, that the truth just announced may be still more fully confirmed, it is found that by compressing the uterine caruncles between the fingers, about a spoonful of the nutritive fluid in question may be obtained from each of them, as from a nipple, unmixed with blood, which is not obtained even with forcible pressure. Moreover, the caruncle thus milked and emptied, like a compressed sponge, contracts and becomes flaccid, and is seen to be pierced with a great number of holes. From everything, therefore, it appears that these caruncles are
32
