348 ON GENERATION. 



the egg, (for nothing is its own author,) and that the said 

 vital principle (anima) passes from the egg into the punctum 

 saliens, presently into the heart, and thence into the chick. 



Moreover, if the egg have a prolific virtue, and a vegetative 

 soul, by which the chick is constructed, and if it owe them, 

 as is allowed on all hands, to the semen of the cock; it is 

 clear that this semen is also endowed with an active princi- 

 ple (anima.) For such is Aristotle's opinion, when he ex- 

 presses himself as follows : " As to whether the semen has a 

 vital principle (anima) or not, the same reasoning must be 

 adduced which we have employed in the consideration of other 

 parts. For no active principle (anima) can exist, except in 

 that thing whose vital principle it is ; nor can there be any 

 part which is not partaker of the vital principle, except it be 

 equivocally, as the eye of a dead man. We must, therefore, 

 allow, both that the semen has an active principle (anima) and 

 is potential." 



Now from these premises, it follows that the male is the 

 primary efficient in which the ratio and forma reside, which 

 produces a seed or rather a prolific geniture, and imparts it, 

 imbued as it is with an anima vegetativa (with which also the 

 rest of its parts are endowed) to the female. The introduction 

 of this geniture begets such a movement in the material of the 

 hen, that the production of an animate egg is the result, and 

 from thence too the first particle of the chick is animated, 

 and afterwards the whole chick. And so, according to Aris- 

 totle, either the same soul passes, by means of some metem- 

 psychosis, from the cock into his geniture, from the geniture 

 into the material of the female, thence into the egg, and from 

 the egg into the chick; or else, it is raised up in each of the 

 subsequent things by its respective antecedent ; namely, in 

 the seed of the male by the male himself, in the egg by the 

 seed, last in the chick by the egg, as light is derived from light. 



The efficient, therefore, which we look for in the egg, to explain 

 the birth of the chick, is the vital principle (anima) ; and there- 

 fore, the vital principle of the egg ; for, according to Aristotle, 

 a soul does not exist except in that thing whose soul it is. 



But it is manifest, that the seed of the male is not the 

 efficient of the chick ; neither as an instrument capable of 

 forming the chick by its motion, as Aristotle would have it, 



