vi COLOURS OF PLANTS 409 



mena of colour in the organic world. I have shown reasons 

 for believing that its presence, in some of its infinitely-varied 

 hues, is more probable than its absence, and that variation of 

 colour is an almost necessary concomitant of variation of struc- 

 ture, of development, and of growth. It has also been shown 

 how colour has been appropriated and modified both in the 

 animal and vegetable worlds for the advantage of the species 

 in a great variety of ways, and that there is no need to call 

 in the aid of any other laws than those of organic develop- 

 ment and " natural selection " to explain its countless modifi- 

 cations. From the point of view here taken, it seems at once 

 improbable and unnecessary that the lower animals should 

 have the same delicate appreciation of the infinite variety 

 and beauty, of the delicate contrasts and subtle harmonies of 

 colour, which are possessed by the more intellectual races of 

 mankind, since even the lower human races do not possess it. 

 All that seems required in the case of animals is a perception 

 of distinctness or contrast of colours; and the dislike of so 

 many creatures to scarlet may perhaps be due to the rarity 

 of that colour in nature, and to the glaring contrast it offers 

 to the sober greens and browns which form the general cloth- 

 ing of the earth's surface, though it may also have a direct 

 irritating effect on the retina. 



The general view of the subject now given must convince 

 us that, so far from colour being as it has sometimes been 

 thought to be unimportant, it is intimately connected with 

 the very existence of a large proportion of the species of the 

 animal and vegetable worlds. The gay colours of the butter- 

 fly and of the Alpine flower which it unconsciously fertilises 

 while seeking for its secreted honey, are each beneficial to its 

 possessor, and have been shown to be dependent on the same 

 class of general laws as those which have determined the 

 form, the structure, and the habits of every living thing. 

 The complex laws and unexpected relations which we have 

 seen to be involved in the production of the special colours of 

 flower, bird, and insect must give them an additional interest 

 for every thoughtful mind; while the knowledge that, in 

 all probability, each style of coloration, and sometimes the 

 smallest details, have a meaning and a use must add a new 

 charm to the study of nature. 



