CHAPTER V. 



THE COLOUR SENSE. 



THE previous considerations lead us, naturally, to enquire in what 

 manner the sense of colour is perceived. 



In thinking over this obscure subject, the opinion has steadily 

 gathered strength that form and colour are closely allied ; for form 

 is essential to pattern; and colour without pattern, that is to say, 

 colour indefinitely marked, or distributed, is hardly decoration at all, 

 in the sense we are using the term. That many animals possess 

 the power of discriminating form is certain. Deformed or monstrous 

 forms are driven from the herds and packs of such social animals 

 as cattle, deer, and hogs, and maimed individuals are destroyed. 

 Similar facts have been noticed in the case of birds. This shows a 

 power of recognising any departure from the standard of form, just 

 as the remorseless destruction of abnormally coloured birds, such as 

 white or piebald rooks and blackbirds, by their fellows, is proof of 

 the recognition and dislike of a departure from normal colouring. 

 Authentic anecdotes of dogs recognising their masters' portraits are 

 on record; and in West Suffolk, of late years, a zinc, homely 

 representation of a cat has been found useful in protecting garden 

 produce from the ravages of birds. In this latter case the birds 

 Boon found out the innocent nature of the fraud, for we have noticed, 

 after a fortnight, the amusing sight of sparrows cleaning their beaks 

 on the whilom object of terror. Many fish are deceived with 

 artificial bait, as the pike, with silvered minnows; the salmon, and 

 trout, with artificial flies ; the glitter of the spoon-bait is often most 

 attractive; and mackerel take greedily to bits of red flannel. Bees 

 sometimes mistake artificial for real flowers; and both they and 

 butterflies have been known to seek vainly for nourishment from 



