ON GENERATION. 301 



a seminal fluid, by the mixture of which a conception or ovum 

 should be produced, as physicians commonly suppose. 



Now since everything that has been delivered by the ancients 

 on generation is comprehended in these two opinions, it appears 

 to have escaped every one up to this time, first, why the hen 

 by herself does not generate, like vegetables, but requires a male 

 to be associated with her in the work; and then how the con- 

 ception or ovum is procreated by the male and the female to- 

 gether, or what either of them contributes to the process, and 

 for what end intercourse was established. 



Aristotle, in opposition to the entire tenor of his hypothesis, 

 viz. that the male is to be regarded as the agent, the female 

 as supplying the matter only, when he sees that eggs are actually 

 produced by hens without the concurrence of the male, is 

 compelled to admit that the female is likewise efficient; he 

 was farther not ignorant of the fact that an egg even when ex- 

 truded could preserve itself, nourish itself, increase in size and 

 produce an embryo, as happens with the eggs of fishes ; and he 

 has besides accorded a vital principle to an egg, even to a hy- 

 penemic one. But he endeavours to explain to what extent a 

 female is efficient, and how a hypenemic egg is endowed with 

 a vital principle, in the passage where he says 1 : " Hypenemic 

 eggs admit of generation to a certain point ; for that they can 

 ever go the length of producing an animal is impossible, this 

 being the work of the senses [the sensible soul] . But females 

 and all things that live, as already repeatedly stated, possess 

 the vegetative soul. Wherefore the hypenemic egg as a vege- 

 table is perfect, but as an animal it is imperfect/' By this he 

 seems to insinuate that the hypenemic egg is possessed of a 

 vegetative soul, inasmuch as this is inherent in all things that 

 live, and an egg is alive. In like manner he ascribes to the 

 hen the power of creating and of conferring the vegetative soul ; 

 because all females acquire this virtue, so that a hypenemic egg 

 in so far as it lives as a vegetable is perfect, in so far as it is an 

 animal however it is imperfect. As if a male were not re- 

 quired that a conception or ovum should be produced, and 

 produced perfect ; but that from this ovum an animal should 

 be engendered. Not, I say, that an egg be produced as per- 

 fect in all respects as is the conception of a vegetable; but 

 1 De Gener. Anim. lib. iii, c. 7. 



