GENERATION OF ANIMALS, II. iv. 



vessel and the Aorta,** branch out into many fine 

 blood-vessels, which terminate in the uterus. When 

 these are overfull of nourishment (which owing to its 

 own coldness the female system is unable to concoct), 

 it passes through these extremely fine blood-vessels 

 into the uterus ; but oAnng to their being so narrow 

 they cannot hold the excessive quantity of it, and so 

 a sort of haemorrhage takes place. In women the 

 period is not accurately fixed, but it tends to happen 

 when the moon is waning,* which is what we should 

 expect, since the bodies of animals are colder when 

 their en\-ironment is colder, and the time of new 

 moon is a cold time on account of the disappear- 

 ance '^ of the moon : the same thing explains why 

 the end of the month is stormier than the middle.'* 

 When the residue has changed into blood, the men- 

 strual discharge tends to occur in accordance ^^^th 

 the period just mentioned ; but when the residue 

 has not been concocted, small quantities are secreted 

 from time to time, and this is why " whites " occur 

 in females, even while they are still quite small 

 children. These two secretions of residue, if moder- 

 ate in amount, keep the body in a sound condition, 

 because they constitute an evacuation of the residues 

 which cause disease. If they fail to occur, or occur 

 too plenteously, they are injurious, producing either 

 diseases or a lowering of the body ; and that is why 

 continuous and abundant discharge of " whites " 

 prevents young girls from gro^^•ing. 



Thus the production of this residue by females is, 



Selene. For other references see F. H. A. Marshall, " Sexual 

 Periodicity," in Phil. Tram. Royal Soc. (B), CCXXM 

 (\o. 539), p. 442, n. "^ i.e., complete waning. 



•^ See 777 b 35, n. 



181 



