248 TROPICAL NATURE, AND OTHER ESSAYS. 



valent even now, is however an indication that the fully 

 developed colour-sense is not of primary importance to 

 man. If it had been so, natural selection would long 

 ago have eliminated the disease itself, and its tendency 

 to recur would hardly be so strong as it appears to be. 



Concluding Remarks on the Colour-sense. The pre- 

 ceding considerations enable us to comprehend, both why 

 a perception of difference of colour has become developed 

 in the higher animals, and also why colours require to 

 be presented or combined in varying proportions in order 

 to be agreeable to us. But they hardly seem to afford a 

 sufficient explanation, either of the wonderful contrasts 

 and total unlikeness of the sensations produced in us 

 by the chief primary colours, or of the exquisite charm 

 and pleasure we derive from colour itself, as distinguished 

 from variously-coloured objects, in the case of which 

 association of ideas comes into play. It is hardly con- 

 ceivable that the material uses of colour to animals and 

 to ourselves, required such very distinct and powerfully- 

 contrasted sensations ; and it is still less conceivable 

 that a sense of delight in colour per se should have been 

 necessary for our utilization of it. 



The emotions excited by colour and by music, alike, 

 seem to rise above the level of a world developed on 

 purely utilitarian principles. 



