314 LESSONS FEOM NATURE. [CHAP. X. 



of their suitors &quot; (vol. ii. p. 1 11). Our author, however, only 

 ventures to call it &quot;probable&quot; and he significantly adds: &quot; It 

 is, however, difficult to obtain direct evidence of their capacity 

 to appreciate beauty.&quot; And again he says of the hen bird: &quot;It 

 is not probable that she consciously deliberates ; but she is 

 most excited or attracted by the most beautiful, or melodious, 

 or gallant males&quot; (vol. ii. p. 123). No doubt the plumage, 

 song, &c., all play their parts in aiding the various processes 

 of life ; but to stimulate the sexual instinct, even supposing 

 this to be the object, is one thing -to supply the occasion 

 for the exercise of a power of choice is quite another. Cer 

 tainly we can never admit what Mr. Darwin strongly affirms 

 (vol. ii. p. 124), that an &quot;even occasional preference by the 

 female of the more attractive males would almost certainly 

 lead to their modification.&quot; 



A singular instance is given by Mr. Darwin (vol. ii. p. Ill) 

 in support of his view, on the authority of Mr. J. Weir. It 

 is that of a bullfinch which constantly attacked a reed-bunt 

 ing, newly put into the aviary ; and this attack is attributed 

 to a sort of jealousy on the part of the blackheaded bullfinch 

 of the black head of the bunting. But it is somewhat diffi 

 cult to know how the bullfinch became aware of the colour 

 of the top of his own head ! 



Mr. Alfred Wallace has, in the following passage, well ex- 

 Mr. Wallace pressed two objections to Mr. Darwin s theory of 

 SarwTn. r sexual selection which have also occurred to the 

 minds of others : 



&quot; There are two difficulties in the way of accepting Mr. Darwin s 

 wide generalisation as to the agency of sexual selection in producing 

 the greater part of the colour that adorns the animal world. How are 

 we to believe that the action of an ever-varying fancy for any slight 

 change of colour could produce and fix the definite colours and mark 

 ings which actually characterize species ? Successive generations of 

 female birds choosing any little variety of colour that occurred among 

 their suitors woxild necessarily lead to a speckled or piebald and un 

 stable result, not to the beautiful definite colours and markings we 

 see. . . . How can the individual tastes of hundreds of successive 

 generations of female birds produce any such definite or constant 

 effect ? Some law of necessary development of colour in certain parts 



