MAY 99 



changing their hue when they shift from dark ground 

 to light, or vice versa. The cod and the ling, also, wear 

 a livery similar both in colour and texture to the 

 forests of kelp and tangle wherein they seek their prey. 

 Similarly the pike, gluttonous tyrant of the river and 

 the loch, is so cunningly dappled with olive and grey 

 as to match exactly the water weeds wherein it makes 

 ambush. So effective is the camouflage that one 

 standing beside still water will probably detect a pike 

 from its shadow on the bottom before seeing the fish 

 itself. 



But how about free-swimming fishes like the salmon, 

 the herring, and the sprat, and, in fresh water, the 

 grayling, the dace, and the roach? Surely if any 

 human being in his senses wished to avoid being 

 conspicuous he would not clothe himself from head to 

 foot in shining armour. Yet that is precisely the 

 raiment assigned to these and many other fishes. The 

 sides of a fresh-run salmon and the scales of a herring 

 gleam with the lustre of burnished silver, well calculated, 

 one should think, to destroy all chance of concealment, 

 for nothing catches the eye so readily as glitter. Never- 

 theless, it has been reserved for Dr. Francis Ward of 

 Ipswich to prove by demonstration that this panoply of 

 brilliant scales actually serves to mask the fish's 

 presence. He found that when he put a roach or other 

 silvery fish in a white basin of water and held brightly 

 coloured strips of paper near it, the colours were 

 clearly reflected from the fish's side. ' Not only/ says 

 he, ' will the body of the fish show these colours, but 

 they will appear more brilliant on it than on the strips 



