48 USUAL SIZE OF TROUT. 



ing principle, capable of being extracted by alcohol ; and 

 the quantity of this matter present in the flesh of both 

 trout and salmon, depends entirely on the nature and 

 abundance of their food. It is supposed to be most 

 abundantly secreted by those fish that are in the habit 

 of feeding almost exclusively on small fish and crusta- 

 ceans at the bottom of the water. And it is a fact well 

 known to many experienced anglers, that in every river 

 there are certain fish which feed almost exclusively upon 

 worms, caddies, crustaceans, and minnows at the bottom, 

 and seldom or never rise to the fly ; while others, again, 

 feed almost entirely upon insects on the surface during 

 the time they last. The former fish may easily be dis- 

 tinguished from the latter, by their exhibiting larger 

 and more numerous black and fewer red spots on their 

 sides, and by their bellies being of a shining silvery 

 white, and flat underneath. The flesh of those fish will 

 be generally of a fine pink colour, and rich in flavour ; 

 while that of the fly-taking individuals, will be com- 

 paratively white, flabby, and insipid. They will also 

 be found much thicker at the shoulders in proportion to 

 their length than the latter. Numbers of this kind of 

 trout are to be found in the deeper parts of the Till, 

 where caddies and every kind of bottom feed is abundant. 

 As an evidence that the size, colour, and quality of the 

 flesh of all descriptions of trout depend mainly, if not 

 entirely, on the quality of the water, and the nature and 

 abundance of the food, I may state, that if a small burn 

 trout, as dusky as a Hotentot, is transferred from its 

 native stream into a stew containing clear water, and is 



