The Colour Sense. 33 



the gaudy painted flowers on cottage wall-papers. Sir John 

 Lubbock has demonstrated the existence of a colour sense in bees, 

 wasps, and ants ; and the great fact that flowers are lures for insects 

 proves beyond the power of doubt that these creatures have a very 

 strong faculty for perceiving colour. 



The pale yellows and white of night-flowering plants render 

 them conspicuous to the flower-haunting moths ; and no one who 

 has ever used an entomologist's lantern, or watched a daddy-long- 

 legs (Tipula) dancing madly round a candle, can fail to see that 

 intense excitement is caused by the flame. In the dim shades of 

 night the faint light of the flowers tells the insects of the land of 

 plenty, and the stimulus thus excited is multiplied into a frenzy by 

 the glow of a lamp, which, doubtless, seems to insect eyes the 

 promise of a feast that shall transcend that of ordinary flowers, as 

 a Lord Mayor's feast transcends a homely crust of bread and 

 cheese. 



We take it, then, as proven that the colour sense does exist, at 

 least, in all creatures possessing eyes. But there are myriads of 

 animals revelling in bright tints ; such as the jelly-fishes and 

 anemones, and even lower organisms, in which eyes are either 

 entirely wanting or are mere eye-specks, as will be explained in the 

 sequel. How these behave with regard to colour is a question 

 that may, with propriety, be asked of science, but to which, at 

 present, we can give no very definite reply. Still, certain modern 

 researches open to us a prospect of being able, eventually, to decide 

 even this obscure problem. 



The question, however, is not a simple one, but involves two 

 distinct principles ; firstly, as to how colour affects the animal 

 coloured, and, secondly, how it affects other animals. In other 

 words, How does colour affect the sensibility of its possessor? and 

 how does it affect the sense organs of others % 



To endeavour to answer the first question we must start with 

 the lowest forms of life, and their receptivity to the action of light ; 

 for, as colour is only a differentiation of ordinary so-called white 

 light, we might a 'priori expect that animals would show sensibility 

 to light as distinguished from darkness, before they had the power 

 of discriminating between different kinds of light. 



This appears to be the case, for Engelmann has shown* that many 



* Pfliiger's Archiv. f. d. ges. Phys. Bd. xxix, 1882, quoted by Eomanes. Mental 

 Evolution, p. 80, 1883. Op. cit. p. 80. 



