GENERATION OF ANIMALS, V. iii. 



Of all animals human beings are the ones which Baldness. 

 go bald most noticeably ; but still baldness is a 

 general and v^idespread condition. Thus, although 

 some plants are evergreen, others shed their leaves, 

 and birds which hibernate shed their feathers. Bald- 

 ness, in those human beings whom it affects, is a com- 

 parable condition to these. Of course, a partial and 

 gradual shedding of leaves takes place in all plants, 

 and of feathers and hair in those animals that have 

 them ; but it is when the shedding affects the whole 

 of the hair, feathers, etc., at once that the condition is 

 described by the terms already mentioned (baldness, 

 moulting," etc.). The cause of this condition is a 

 deficiency of hot fluid, the chief hot fluid being 

 greasy fluid, and that is why greasy plants tend more 

 to be evergreen than others. However, we shall 

 have to deal with the cause of this condition so far 

 as plants are concerned in another treatise, since in 

 their case there are other contributory causes of it. 

 Now in plants this condition occurs in winter : this 

 seasonal change overrides in importance the change 

 in the time of life. The same is true of the hibernat- 

 ing animals ; they too are in their nature less fluid 

 and less hot than human beings. For human beings, 

 however, it is the seasons of life which play the part 

 of summer and winter ; and that is why no one goes 

 bald before the time of sexual intercourse, and also 

 why that is the time when those who are naturally 

 prone to intercourse go bald. The reason is that 

 the effect of sexual intercourse is to cool, as it is the 

 excretion of some of the pure, natural heat, and the 



the context, I have kept the point by substituting " moult- 

 ing " : the Berlin edition and others actually insert the word 

 for " moulting " into the Gk. text. 



523 



