GENERATION OF ANIMALS, IV. i. 



to secrete the residue in a pure condition ; and as in the 

 there is an instrument for every abiUty or faculty, for ®™ '^°" 

 the one which yields its product in a more finisheck 

 condition and for the one which yields the same pro- 

 duct in a less finished condition ; and as male and 

 female stand opposed in this way (" able " and " un- 

 il)le " being used in more senses than one ^) ; there- 

 •re of necessity there must be an instrument * both 

 for the male and for the female ; hence the male has 

 the perineos '^ and the female has the uterus. Nature 

 gives each one its instrument simultaneously with its 

 ability, since it is better done thus. Hence each of 

 these regions of the body gets formed simultaneously 

 with the corresponding secretions and abilities, just 

 as the abihty to see does not get perfected without 

 eyes, nor the eye without the abiUty to see, and 

 just as the gut and the bladder are perfected simul- 

 taneously ^\•ith the ability to form the residues. Now 

 as the stuff out of which the parts are formed is the 

 same as that from which they derive their growth,*^ 

 namely the nourishment, we should expect each of 

 the parts to be formed out of that sort of material 

 and that sort of residue which it is fitted to receive. 

 Secondly, and on the contrary, it is, as we hold, 

 formed in a way out of its opposite. Thirdly, in 

 addition, it must be laid down that, assuming the ex- 

 tinction of a thing means its passing into its opposite 

 condition, then also that which does not get mastered 

 by the agent which is fashioning it must of necessity 

 change over into its opposite condition.* With these 



^ For this distinction between the grades of nourishment, 

 see 744 b 32 if. 



' This is explained at length at 768 a 1 fF. The whole of the 

 present passage should be read in conjunction with the later 

 and fuller discussion. See also 766 b 1 5 if. 



389 



