150 BOOK OF THE BLACK BASS. 



from golden-yellow to crimson and greenish-black, are 

 almost infinite, and depend in a great measure on the 

 nature of its food, for the colors are always the most 

 brilliant in those fish that feed on the water shrimp." 



Near Waterville, Waukesha County, Wisconsin, is the 

 extensive trout hatching establishment of Mr. H. F. Dous- 

 man, where a number of fine springs form a considerable 

 stream after leaving the ponds and flumes, and into which 

 a number of brook trout have escaped at various times, 

 so that finally it became well stocked with trout, which 

 propagate naturally in the stream. The trout which are 

 reared artificially are kept in covered plank flumes, and in 

 open ponds, and are fed principally on chopped liver; 

 those in the ponds getting some addition to this fare, how- 

 ever, in aquatic flies, insects, etc. The stream contains a 

 great many crawfish, Avhich often do much damage to the 

 dams and ditches of adjacent cranberry marshes. Upon 

 visiting this establishment, I was at once struck with the 

 remarkable difference in - the colors of the trout in the 

 flumes, in the ponds, and in the stream. Those in the 

 flumes were quite dull in appearance ; those in the ponds 

 were brighter; while those in the stream were the most 

 brilliantly colored trout I ever saw, caused, no doubt, by 

 their feeding upon the Crustacea with which the stream 

 abounded. The dull color of the trout in the flumes was 

 partly owing to their shaded condition. 



Not only does the character of the food influence the 

 external coloring of the Salmunida', but the tint of the 

 flesh, if I may so call it, is also affected by the same cause; 

 thus Professor Agassiz states that the most beautiful salmon- 

 trout are found in waters which abound in Crustacea, direct 

 experiments having shown to his satisfaction that the 



