THE NATURAL 



sexes in gorilla and orang-outang is in the males having 

 vocal sacks descending over the chest to the arm-pits. 



Thanks to these air-reservoirs, these bag-pipe bags, 

 inflatable at will, the male can howl for a very long 

 time and with great violence; the females' sacks are very 

 small. Other monkeys, notably howling apes, are pro- 

 vided with these air-chambers, as are also certain other 

 mammifers well known for the extravagance of their 

 cries: polecats and pigs. Birds and batrachians have 

 analogous organs. 



Dimorphism of men and women varies according to 

 race or rather according to species. Very feeble in most 

 blacks and reds it is accentuated among Semites, Aryans, 

 and Finns. But in man as in all animals of separate 

 sexes one must differentiate between the primary dimor- 

 phism, which is necessary and produced by the specializa- 

 tion of sexual organs, and the secondary dimorphism with 

 which the relation of sex is less evident or wholly un- 

 certain. Limited to the non-sexual elements, human 

 dimorphism is very feeble. Almost null in infancy, it 

 develops with approaching puberty, is maintained dur- 

 ing the genital period, and diminishes, sometimes almost 

 to vanishing point, in old age. It varies individually, 

 even during the years of greatest reproductivity, in males 

 feebly sexed and in women heavily sexed: that is to say 

 there are men and women whose type closely approaches 

 the type-ideal formed by the fusion of sexes; neither one 

 nor the other escapes the radical dimorphism imposed 

 by the difference of sexual organs. 



Leaving aside exceptions, one observes a mediocre 

 and constant dimorphism between men and women, 

 SO 



