200 THE COLOUR-SENSE IN FISHES 



will see it more or less on its own level and 

 often against a background, say of weeds or 

 shore ; and this is also true to some extent in 

 the case of the salmon, which frequently follows 

 the fly a long way before making the final dash. 

 Whereas, as a rule, the trout must see the fly 

 against the sky and light, presenting therefore 

 only a dark outline. 



The same friend was good enough to call 

 attention to a passage in Herbert Spencer's 

 Autobiography, bearing on the subject under 

 consideration : 



' My constitutional tendency to call in question 

 current opinions, was manifested when fishing, 

 as on other occasions. While in Wales the 

 year before, occupied in writing on Psychology 

 and occasionally casting a fly over a stream or 

 llyn, it occurred to me that, considering how 

 low is the nervous organization of fishes, it is 

 unlikely that they should be able to discrimi- 

 nate so nicely as the current ideas respecting 

 artificial flies imply unlikely, too, that they 

 should have such erratic fancies as to be taken 

 by combinations of differently coloured feathers, 

 like no living creature ever seen. 



( I acted upon my scepticism, and ignored the 

 local traditions. Hearing me vent my heresies, 

 the farmer, tenant of Beoch, challenged me to 



