296 ON GENERATION. 



EXERCISE THE THIRTY-THIRD. 



The male and the female are alike efficient in the business of 

 generation. 



The medical writers with propriety maintain, in opposition 

 to the Aristotelians, that both sexes have the power of acting 

 as efficient causes in the business of generation; inasmuch as 

 the being engendered is a mixture of the two which engender: 

 both form and likeness of body, and species are mixed, as we 

 see in the hybrid between the partridge and common fowl. 

 And it does indeed seem consonant with reason to hold that 

 they are the efficient causes of conception whose mixture appears 

 in the thing produced. 



Aristotle entertaining this opinion says } " In some animals it 

 is manifest that such as the generator is, such is the engendered; 

 not, however, the same and identical, not one numerically, but 

 one specifically, as in natural things. A man engenders a man, if 

 there be nothing preternatural in the way, as a horse [upon an 

 ass] engenders a mule, and other similar instances. For the mule 

 is common to the horse and the ass; it is not spoken of as an 

 allied kind ; yet may horse and ass both be there conjoined in 

 a hybrid state." He says farther in the same place : " It is 

 enough that the generator generate, and prove the cause that 

 the species be found in the matter: for such and such an entire 

 species is still found associated with such and such flesh and 

 bones here it is Gallias, there it is Socrates." 



Wherefore if such an entire form, as a mule, be a mixture 

 of two, viz. : a horse and an ass, the horse does not suffice to 

 produce this form of a mule in the ' matter/ but, as the entire 

 form is mixed, so another efficient cause is contributed by the 

 ass and added to that supplied by the horse. That, therefore, 

 which produces a mule compounded of two, must itself be an 

 ' adequate efficient,' and mixed, if only ' univocal/ For ex- 

 ample, this woman and that man engender this Socrates ; not 

 in so far as they are both human beings, and of one and the same 



1 Metaphys. lib. vii, cap. 8. 



