The Theory of Sexual Selection. 391 



We may next proceed to consider the objections 

 which have been brought against the theory of sexual 

 selection. And this is virtually the same thing as 

 saying that we may now consider Mr. Wallace's views 

 upon the subject. 



Reserving for subsequent consideration the most 

 general of these objections namely, that at best the 

 theory can only apply to the more intelligent animals, 

 and so must necessarily fail to explain the phenomena 

 of beauty in the less intelligent, or in the non- 

 intelligent, as well as in all species of plants we may v 

 take seriatim the other objections which, in the opinion 

 of Mr. Wallace, are sufficient to dispose of the theory 

 even as regards the higher animals. 



In the first place, he argues that the principal 

 cause of the greater brilliancy of male animals in 

 general, and of male birds in particular, is that they 

 do not so much stand in need of protection arising 

 from concealment as is the case with their respective 

 females. Consequently natural selection is not so 

 active in repressing brilliancy of colour in the males, 

 or, which amounts to the same thing, is more active 

 in " repressing in the female those bright colours 

 which are normally produced in both sexes by general 

 laws." 



Next, he argues that not only does natural selection 

 thus exercise a negative influence in passively per- 

 mitting more heightened colour to appear in the 

 males, but even exercises a positive influence in 

 actively promoting its development in the males, 

 while, at the same time, actively repressing its ap- 

 pearance in the females. For heightened colour, he 

 says, is correlated with health and vigour ; and as there 



