Page:The Works of William Harvey (part 1 of 2).djvu/402

 that it should be imbued with the animal principle. The egg, consequently, is formed by the hen, but it is made prolific by the cock.

Aristotle adds in the same place : " There is a distinction of sexes through the whole class of birds. And therefore it happens that the hen perfects her egg, not yet influenced by the intercourse of the male, in so far as it is a plant ; but as it is not a plant, there she does not perfect it : nor does any- thing come of it which engenders. For neither has it arisen simply, like the seed of a plant, nor like an animal conception, by intercourse/' He is here speaking of the wind egg; by and by he adds : " But those eggs that are conceived through in- tercourse are already characterized in a portion of the albumen : such eggs become fruitful through the male which first copu- lated, for they are then supplied with both principles."

By this he seems to confess that the female is also effective in the work of generation, or is possessed of the faculty of en- gendering; because in every female there inheres a vegetative soul, whose faculty it is to engender. And, therefore, when he is speaking of the differences between the male and female, he still acknowledges both as generative ; for he says : " We call that animal male which engenders in another, female that which engenders in itself." From his own showing, therefore, both engender; and as there is a vegetative soul inherent in both, so is there also its faculty of generation. But how they differ has already been shown in the History of the Egg : the hen generates of herself without the concurrence of the cock, as a plant out of itself produces fruit ; but it is a wind egg that is thus produced : it is not made fruitful without the con- currence of the cock either preceding or succeeding. The female generates, then, but it is only up to a certain mark, and the concurrence of the male is requisite that this faculty of engen- dering be made complete, that she may not only lay an egg, but such an egg as will, under favorable circumstances, produce a pullet. The male appears to be ordained by nature to supply this deficiency in the generative powers of the female, as will be clearly shown by and by, and that that which the female of herself cannot accomplish, viz. the production of a fruitful egg, may be supplied and made good by the act of the male, who imparts this virtue to the fowl or the egg.