TROUT FLY-FISHING IN AMERICA 



Then the trout in section 2 was placed in section i and 

 became fully changed in coloration in fifteen hours. 



During this experiment no account was taken of the 

 character of the food eaten by the trout, but as this test 

 was made in August probably the food consisted largely 

 of flies and insects. 



This test was made under natural conditions, but in 

 order to go further and fully determine the effect of dif- 

 ferent colored water bottoms upon the coloration of trout 

 other and unnatural conditions were substituted. 



Three trout were taken, as in the other case, of about 

 the same size, and placed in three glass tanks. One tank 

 rested upon a black bottom, and the sides of the tank were 

 covered with a dead black cloth. One tank rested upon a 

 white bottom, and the sides of the tank were covered with 

 a dead white cloth. One tank rested upon a yellowish or 

 brownish-yellow bottom, and nothing was placed on the 

 sides of the tank. The trout were fed on worms and liver. 

 These tanks were in a room, and resting on large tables, 

 and the curtains to the windows were pulled down. The 

 ceiling of the room was of a drab color. 



These trout were handled the same as those in the 

 brook experiment, and the results obtained were practi- 

 cally identical, except that none of the different colora- 

 tions were quite as pronounced, and it took thirty to forty 

 hours for a complete change to take place. 



As illustrating the rapidity with which the coloration 

 of trout will take place, I would say that I have on several 

 occasions, early in the spring, while fishing small brooks 



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