200 Animal Life and Intelligence. 



factor, natural elimination being another factor ; both 

 being operative at the same time, and each contributing to 

 that marked differentiation of male and female which we 

 find to prevail in certain classes of the animal kingdom. 



But Mr. Wallace will not accept this compromise. He 

 rejects preferential mating altogether, or, in any case, 

 denies that through its agency secondary sexual characters 

 have been developed. He admits, of course, the striking 

 and beautiful nature of some of these characters ; he 

 admits that the male in courtship takes elaborate pains to 

 display all his finery before his would-be mate ; he admits 

 that the " female birds may be charmed or excited by the 

 fine display of plumage by the males ; " but he concludes 

 that " there is no proof whatever that slight differences in 

 that display have any effect in determining their choice of 

 a partner."* 



How, then, does Mr. Wallace himself suppose that 

 these secondary sexual characters have arisen ? His 

 answer is that " ornament is the natural outcome and 

 direct product of superabundant health and vigour," and 

 is "due to the general laws of growth and development." f 

 At which one rubs one's eyes and looks to the title-page to 

 see that Mr. Wallace's name is really there, and not that 

 of Professor Mivart or the Duke of Argyll. For, if the 

 plumage of the argus pheasant and the bird of paradise 

 is due to the general laws of growth and development, 

 why not the whole animal ? If Darwin's sexual selection 

 is to be thus superseded, why not Messrs. Darwin and 

 Wallace's natural selection ? 



Must we not confess that Mr. Wallace, for whose genius 

 I have the profoundest admiration, has here allowed him- 

 self to confound together the question of origin and the 

 question of guidance or direction ? Natural selection by 

 elimination and sexual selection through preferential 



* " Darwinism," chap. x. 



t "Darwinism," p. 295. Messrs. Geddes and Thomson, " The Evolution 

 of Sex," p. 28, also contend that " combative energy and sexual beauty rise 

 pari passu with male katabolism." 



