THE SEXES, AND CRITICISM OF SEXUAL SELECTION: 2 ^ 



upon an inexplicable variation, and is traced back to a pathological and 

 mechanical origin in the emphatic maleness of the organism. The line 

 of variation being thus given, it is of course conceivable that natural 

 selection may have accelerated it. 



So too, though again the physiological details are scanty, the 

 superabundant growth of hair and feathers may be interpreted, in some 

 measure through getting rid of waste products, for we shall see later 

 how local katabolism favors cell-multiplication. Combs, wattles, and 

 skin-excrescences point to a predominance of circulation in the skin 

 of the feverish males, whose temperatures are known in some cases to 

 be decidedly higher than those of the females. Even skeletal weapons, 

 like antlers, may be similarly interpreted; while the exaggerated 

 activity of the scent-glands is another expedient for excreting waste. 



In regard to horns, feathers, and the like, in association with vigor- 

 ous circulation, two sentences from Rolph may be quoted : ' ' The 

 exceedingly abundant circulation, which periodically occurs in the at 

 first soft frontal protuberances of stags, admits and conditions the 

 colossal development of horn and delicate ensheathing velvet. ... In 

 the same way the rich flow of blood in the feather-papillae con- 

 ditions the immense growth of the feathers, . . . and the same is true 

 of hairs, spines, and teeth." 



Some of the even subtler differences between the sexes are of 

 interest in illustrating the general antithesis. Thus in the love-lights 

 of the Italian glow-insect (Lziciola) the color is said to be identical 

 in the two sexes, and the intensity is much the same. That of the 

 female, however, who is in other respects rather male-like in her 

 amatory emotions, is more restricted. It is interesting further to 

 notice that the rhythm of the light in the male is more rapid and the 

 flashes are briefer, while that of the female is longer and the flashes 

 more distant and tremulous. This illustration may thus serve, in con- 

 clusion, as a literally illumined index of the contrasted physiology of 

 the sexes. 



V. Sexual Selection: its Limit as an Explanation. — We 

 are now in a better position to criticise Mr. Darwin's theory. On his 

 view, males are stronger, handsomer, or more emotional, because 

 ancestral forms happened to become so in a slight degree. In other 

 words, the reward of breeding success gradually perpetuated and per- 

 fected a casual advantage. According to the present view, males are 

 stronger, handsomer, or more emotional, simply because they are 

 males, — that is, of more active physiological habit than their mates. 

 In phraseology which will presently become more intelligible and con- 

 crete, the males live at a loss, are more katabolic, — disruptive changes 

 tending to preponderate in the sum of changes in their living matte;' or 



