CHAPTER XVIII 



A Question of Heredity 



' Much information respecting the habits of 

 aquatic insects can be extracted from anglers 

 by those who speak their language,' says 

 Professor Miall in his ' Natural History of 

 Aquatic Insects.' If this is true in regard to 

 the flies that trout devour, it is even more 

 so in regard to the trout. There have been 

 natural histories of the trout and to spare 

 from a non-angling point of view written 

 during the last few years, but not one of 

 them has attempted to deal at all thoroughly 

 with the exceedingly interesting question of 

 whether the trout of to-day are really wiser 

 than their forebears, and whether, if they are 

 wiser, their increased sagacity is hereditary 

 or merely acquired by each trout through 

 bitter experience of the hooks and the mani- 



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