150 THE LESSON OF EVOLUTION 



less degenerate organs or vestiges, but they are com- 

 paratively few ; and still fewer are the characters 

 which we may suppose to be due to correlation of 

 growth. The great majority remain unexplained. 

 Ten or twelve years later Darwin recognised the 

 force of this objection; and, in the "Descent of 

 Man," he says: "In the earlier editions of my 

 ' Origin of Species ' I perhaps attributed too much 

 to the action of natural selection or survival of the 

 fittest. I have altered the fifth edition of the 

 ' Origin ' so as to confine my remarks to adaptive 

 changes of structure ; but I am convinced from the 

 light gained during the last few years that very 

 many structures which now appear to be useless will 

 hereafter prove to be useful, and will therefore come 

 within range of natural selection. Nevertheless, I 

 did not formerly consider sufficiently the existence 

 of structures which, so far as we can at present 

 judge, are neither beneficial nor injurious, and this 

 I believe to be one of the greatest oversights as yet 

 detected in my work. It is, as I can now see, pro- 

 bable that all organic beings, including man, possess 

 peculiarities of structure which neither are now, nor 

 were formerly, of any service to them, and which 

 therefore are of no physiological importance." 39 



Dr. Wallace, however, still argues that these 

 characters are not really useless, but that we suppose 

 them to be so because we are so very ignorant of 

 the habits of animals. He thinks it is impossible 

 to prove that any character is not, nor ever has been, 

 useful to its possessor, or that it is not necessarily 



39 "The Descent of Man," 2nd edition, p. 61. 



