394 Darwin, and after Darwin. 



between brilliancy and ornamentation or between 

 colour as merely ' heightened," and as distinctively 

 decorative. Yet there is obviously the greatest pos- 

 sible difference between these two things. We may 

 readily enough admit that a mere heightening of al- 

 ready existing coloration is likely enough at all 

 events in many cases to accompany a general increase 

 of vigour, and therefore that natural selection, by pro- 

 moting the latter, may also incidentally promote the 

 former, in cases where brilliancy is not a source of 

 danger. But clearly this is a widely different thing from 

 showing that not only a general brilliancy of colour, 

 but also the particular disposition of colours^ in the 

 form of ornamental patterns, can thus be accounted 

 for by natural selection. Indeed, it is expressly in 

 order to account for the occurrence of such ornamental 

 patterns that .Mr. Darwin constructed his theory of 

 sexual selection ; and therefore, by thus virtually 

 ignoring the only facts which that theory endeavours 

 to explain, Mr. Wallace is not really criticizing the 

 theory at all. By representing that the theory has to 

 do only with brilliancy of colour, as distinguished 

 from disposition of colours, he is going off upon a 

 false issue which has never really been raised \ Look, 

 for example, at a peacock's tail. No doubt it is suf- 

 ficiently brilliant ; but far more remarkable than its 

 brilliancy is its elaborate pattern on the one hand, and 

 its enormous size on the other. There is no conceiv- 

 able reason why mere brilliancy of colour, as an ac- 

 cidental concomitant of general vigour, should have 

 run into so extraordinary, so elaborate, and so bcau- 



1 Note C. 



