INTRODUCTION 



Colour in Nature and in Organisms — Characters of the 

 Colours of Organisms and their General Importance — 

 Method of Treatment Adopted. 



To those who have not followed closely recent 

 developments of Evolution Theory, the connection 

 between Biology and Colour may seem very remote. 

 The phenomena of colour, it may be said, are entirely 

 the province of the physicist ; that the sky is blue 

 and the grass green are two facts of similar nature, 

 and the one is as inexplicable as the other. So 

 in general it may be said that it is simply a fact 

 of experience that most objects, whether animate 

 or inanimate, present themselves to our eyes as 

 coloured, and that it is therefore absurd to separate 

 the phenomena of colour as they appear in organisms 

 from the similar phenomena of inorganic nature. A 

 little reflection will, however, convince every one that 

 the biologist cannot afford to be indifferent to the 

 colours of the organisms with which he has to deal. 

 In the first place, they attract his attention because 

 of their frequently great intrinsic beauty and their 

 arrangement into patterns and markines which mav 



