GENERATION OF ANIMALS, IV. vii.-viii. 



^ome inability, and is unable to complete her woi'k 

 and to bring the process of formation to its consmii- 

 mation ; that is why the mola lasts on into old age or 

 at any rate for a considerable time, for in its nature 

 it is neither a finished product nor yet something 

 wholly alien) ; since the cause of its hardness is the 

 lack of concoction, just as underdone nseat is another 

 instance of lack of concoction. 



But there is a puzzle here. Why is it that this 

 phenomenon does not occur in the other animals .'' 

 (unless of course it does, but has entirely escaped 

 observation). We must take the reason to be that 

 alone of all animals women are liable to uterine affec- 

 tions ; they produce an excess of menstrual evacua- 

 tions and cannot concoct them ; and so, when the 

 fetation has been " set," formed out of a liquid which 

 is difficult to concoct, then what is called the mola is 

 produced ; and thus it is not surprising that this takes 

 place chiefly in women if not exclusively in them. 



Milk is produced towards the time of parturition VIII 

 in those female animals which are internally vivipar- ^'^'"^" 

 ous, and it is (1) of a useful and serviceable quality," 

 for Nature has provided animals with it so that they 

 may nourish their young extei'nally, and she has so 

 arranged that it is neither deficient nor excessive in 

 any way at that time ; this we actually observe to 

 obtain unless some accident contrary to nature 

 occurs. In the case of the other animals, as there is 

 but a single period of gestation, the concoction of the 

 milk coincides with that ; in man, however, as there 

 are more periods than one,'' the milk must of neces- 

 sity be available at the earliest of the possible dates ; 

 hence in women the milk, which is useless until seven 

 months are up, at that point becomes useful and 



467 



