Page:The Works of William Harvey (part 1 of 2).djvu/455

 EXERCISE THE FORTY-NINTH.

The inquiry into the efficient cause of the chick is one of great difficulty.

The discussion of the efficient cause of the chick is, as we have said, sufficiently difficult, and all the more in consequence of the various titles by which it has been designated. Aris- totle, indeed, recites several efficient causes of animals, and numerous controversies have arisen on the subject among writers, (these having been particularly hot between medical authors and Aristotelians,) who have come into the arena with various explanations, both of the nature of the efficient cause and of the mode of its operation.

And indeed the Omnipotent Creator is nowhere more con- spicuous in his works, nowhere is his divinity more loudly proclaimed, than in the structure of animals. And though all know and admit that the offspring derives its origin from male and female, that an egg is engendered by a cock and a hen, and that a pullet proceeds from an egg, still we are not informed either by the medical schools or the sagacious Aristotle, as to the manner in which the cock or his semen fashions the chick from the egg. For from what we have had occasion to say of the generation of oviparous and other animals, it is sufficiently obvious that neither is the opinion of the medical authorities admissible, who derive generation from the admixture of the seminal fluids of the two sexes, nor that of Aristotle, who holds the semen masculinum for the efficient, and the menstrual blood for the material cause of procreation. For neither in the act of intercourse nor shortly after it, is aught transferred to the cavity of the uterus, from which as matter any part of the foetus is immediately constituted. Neither does the " geniture" proceeding from the male in the act of union (whether it be animated or an inanimate instrument) enter the uterus ; neither is it attracted into this organ ; neither is it stored up within the fowl ; but it is either dissipated or escapes.