the membranes, to wit, and the fluids, produced by any kind of coagulation j neither is there any thing like curdled milk to be discovered in the uterus, as must be obvious from the foregoing exercises. It follows, therefore, and from thence, that neither does the conception, whence the animal springs, as the herb arises from a fruitful seed, comport itself in the manner Aristotle imagined, since this takes place in viviparous animals in the same way as the egg is formed in oviparous animals, as he him- self avows, and as shall be demonstrated by and by in our ob- servations. Because it is certain that eggs of every descrip- tion prolific and barren are engendered and formed by the hen singly, but that fecundity accrues from the male alone ; the cock, I say, contributes neither form nor matter to the egg, but that only by which it becomes fertile and fit to engender a chick. And this faculty the cock confers by his semen (geni- tura), emitted in the act of intercourse, not only on the egg that is already begun, or is already formed, but on the uterus and ovaiy, and even on the body of the fowl herself, in such wise that eggs which have yet to be produced, eggs, none of the matter of which yet exists either in the ovary or in any other part of the body, are thence produced possessed of fecundity.
EXERCISE THE THIRTY-SECOND.
Nor in the manner imagined by physicians.
Conception, according to the opinion of medical men, takes place in the following way : during intercourse the male and female dissolve in one voluptuous sensation, and eject their seminal fluids (geniturse) into the cavity of the uterus, where that which each contributes is mingled with that which the other supplies, the mixture having from both equally the faculty of action and the force of matter; and according to the predomi- nance of this or of that geniture does the progeny turn out male or female. It is farther imagined that immediately after the intercourse, the active and passive principles cooperating, some- thing of the conception is formed in the uterus. For contrary to the Aristotelians, they maintain that the male is no more the
