Characters as Adaptive and Specific. 185 



means of modification." Disregarding the Lamarckian 

 factors — which, even if valid, have but little relation to 

 the present question, seeing that they are concerned, 

 almost exclusively, with the evolution of adaptive 

 characters — it is alleged that natural selection must 

 occupy the whole field, because no other principle 

 of change can be allowed to operate in the presence 

 of natural selection. Now, I fully agree that this 

 statement may hold as regards any principle of change 

 which is deleterious ; but clearly it does not hold 

 as regards any principle which is merely neutral. 

 If any one were to allege that specific characters 

 are frequently detrimental to the species presenting 

 them, he would no doubt lay himself open to the 

 retort that natural selection could not allow such 

 characters to persist ; or, which amounts to the same 

 thing, that it does " necessarily follow from the theory 

 of natural selection" that specific characters can 

 never be in any large number, or in any large 

 measure, harmful to the species presenting them. 

 But where the statement is that specific characters 

 are frequently indifferent — again to use Professor 

 Huxley's term — the retort loses all its relevancy. No 

 reason has ever been shown why natural selection should 

 interfere with merely indifferent characters, supposing 

 such to have been produced by any of the agencies 

 which we shall presently have to consider. Therefore 

 this argument — or rather assertion — goes for nothing. 

 The only other argument I have met with on this 

 side of the question is one that has recently been 

 adduced by Mr. Wallace. He says : — 



" One very weighty objection to the theory that specific 

 characters can ever be wholly useless appears to have been 



