313 ON GENERATION. 



a coagulum, some mixture of the spermatic substances, or other 

 things of the like kind. On the contrary, it is not till long 

 after intercourse that the eggs and conception first commence 

 their existence, among the greater number of animals, and these 

 the most perfect ones ; I mean in the cases where the females 

 have been fruitful and have become pregnant. And that the 

 female is prolific, before any conception is contained in the 

 uterus, there are many indications, as will be hereafter set forth 

 in the history of viviparous animals : the breasts enlarge, the 

 uterus begins to swell, and by other symptoms a change of the 

 whole system is discerned. 



But the hen, though she have for the most part the rudi- 

 ments of eggs in her before intercourse, which are afterwards 

 by this act rendered fruitful, and there be, therefore, something 

 in her immediately after coition, yet even when she, as in the 

 case of other animals, has as yet no eggs ready prepared in the 

 ovary, or has at the time of the intercourse got rid of all she 

 had, yet does she by and by, even after some lapse of time, as if 

 in possession of both principles or the powers of both sexes, ge- 

 nerate eggs by herself after the manner of plants ; and these 

 (I speak from experience) not barren, but prolific. 



Nay, what is more, if you remove all the eggs from beneath 

 a hen that has been fecundated and is now sitting, (after hav- 

 ing already laid all her eggs, and no more remain in the 

 ovary,) she will begin to lay again ; and the eggs thus laid will 

 be prolific, and have both principles inherent in them. 



EXERCISE THE FORTY-FIRST. 



Of the sense in which the hen ma 



efficient :" and of her parturition. 



It has already been said, that the hen is the efficient cause 

 of generation, or an instrument of Nature in this work, not 

 indeed immediately, or of herself; but when rendered prolific 

 by commission from, and in virtue of the male. But as the 

 male is considered by Aristotle to be the first principle of 



