372 ON GENERATION. 



ble in the cavity of the uterus after intercourse -what that 

 prolific contagion or prime conception is ; whether it is cor- 

 poreal and laid up within the female, or is incorporeal ; whether 

 the conception of the uterus be of the same nature or not with 

 the conceptions of the brain, and fecundity be acquired in the 

 same way as knowledge a conclusion, in favour of which there 

 is no lack of arguments ; or, as motion and the animal opera- 

 tions, which we call appetites, derive their origin from the 

 conceptions of the brain, may not the natural motions and the 

 operations of the vegetative principle, and particularly genera- 

 tion, depend on the conception of the uterus? And then 

 we have to inquire how this prolific contagion is of a mixed 

 nature, and is imparted by the male to the female, and by her 

 is transferred to the ovum ? Finally, how the contagious prin- 

 ciple of all diseases and preternatural affections spreads insen- 

 sibly, and is propagated? 



EXERCISE THE FIFTY-FIRST. 



Of the order of generation ; and, first, of the primary genital 

 particle. 



IT will be our business, by and by, when we come to treat 

 of the matter in especial, to show what happens to the female 

 from a fruitful embrace ; what it is that remains with her after 

 this, and which we have still spoken of under the name of con- 

 tagion, by which, as by a kind of infection, she conceives, and an 

 embryo subsequently begins to grow of its own accord. Mean- 

 time, we shall discourse of those things that manifestly appear 

 in connexion with the organs of generation which seem most 

 worthy of particular comment. 



And first, since it appears certain that the chick is produced 

 by epigenesis, or addition of the parts that successively arise, 

 we shall inquire what part is formed first, before any of the 

 rest appear, and what may be observed of this and its particular 

 mode of generation. 



What Aristotle * says of the generation of the more perfect 



1 De Gen. Aniin. lib. ii, cap. 1. 



