THE SEXES, AND CRITICISM OF SEXUAL SELECTION. 23 



secondary sexual characters as part and parcel of the sexual 

 diathesis, — as expressions for the most part of exuberant 

 maleness. Secondly, when the reproductive organs are 

 removed by castration, the secondary sexual characters tend to 

 remain undeveloped. Thus, as Darwin notes, stags never 

 renew their antlers after castration, though normally of course 

 they renew them each breeding" season. The reindeer, where 

 the horns occur on the females as well, is an interesting excep- 

 tion to the rule, for after castration the male still renews the 

 growth. This however merely indicates that the originally sexual 

 characters have become organised into the general life of the 

 body. In sheep, antelopes, oxen, Sec, castration modifies or 

 reduces the horns ; and the same is true of odoriferous glands. 

 The parasitic crustacean Sacciilina has been shown by Delage 

 to effect a partial castration of the crabs to which it fixes itself, 

 and the same has been observed by (jiard in other cases. In 

 two such cases an approximation to the female form of appendage 

 has been observed. Lastly, in aged females, which have ceased 

 to be functional in reproduction, the minor peculiarities of their 

 sex often disappear, and they become liker males, both in 

 structure and habits, — witness the familiar case of "crowing 

 hens." 



From the presupposition, then, of the intimate connection 

 between the sexuality and the secondary characters (which is 

 indeed everywhere allowed), it is possible to advance a step 

 further. Thus in regard to colour, that the male is usually 

 brighter than the female is an acknowledged fact. But pig- 

 ments of many kinds are physiologically regarded as of the 

 nature of waste products. Such for instance is the guanin, so 

 abundant on the skin of fishes and some other animals. 

 Abundance of such pigments, and richness of variety in related 

 series, point to pre-eminent activity of chemical processes in the 

 animals which possess them. Technically expressed, abundant 

 pigments are expressions of intense metabolism. But pre- 

 dominant activity has been already seen to be characteristic of 

 the male sex ; these bright colours, then, are often natural 

 to maleness. In a literal sense animals put on beauty for 

 ashes, and the males more so because they are males, and not 

 primarily for any other reason whatever. We are well aware 

 that, in spite of the researches of Krukenberg, Sorby, MacMunn, 

 and others, our knowledge of the physiology of many of the 

 pigments is still very scanty. Yet in many cases, alike among 



