130 A SCOTTISH FLY-FISHER 



beneficent Nature anxious to assist them in finding 

 concealment from their enemies. It would be interest- 

 ing to learn what these enemies think of Nature's in- 

 terference with their honest efforts to procure a meal ; 

 though, in truth, they have little reason to complain, 

 since they, too, share in her favours. She is quite as 

 ready to help the eaters as the eaten. If with one 

 hand she thoughtfully perfects the means of self-pro- 

 tection bestowed upon the prey, with the other she 

 arms the preyer with increasingly efficient weapons of 

 offence. She entertains herself in pitting each against 

 the other. To the Powers she has given a lesson they 

 have not been slow to learn ; they have proved apt 

 scholars, and, in devilish ingenuity, have even out- 

 done their teacher. The discovery of an effective 

 system of defence stimulates the inventor to the pro- 

 duction of an overpowering method of attack. The 

 armour-plate of great resistance leads inevitably to 

 the shell of high velocity. In reality, animals do 

 not possess the voluntary power ascribed to them ; 

 what change of colour or, to be precise, of tone 

 they undergo is as independent of volition as the 

 blush that mantles the modest maiden's cheek. The 

 trout does not consciously assume the hue of his en- 

 vironment. 



