The Senses and the Nervous System 99 



only was he able to tell the training red from any of the 

 shades of gray, but if he were offered some other shade of 

 red, he would choose that rather than any of the grays. 

 Without any indoctrination, he was aware that there was a 

 relationship between red and pink which did not exist for red 

 and gray! And the final conclusion was that the black bass 

 responds in color vision about like a normal human being 

 looking through a pair of yellowish glasses. 



At this point we must remember that species differ, and 

 that other fish may not be able to do what the black bass can. 

 Black bass and trout are as far apart in the taxonomic scale 

 as, for instance, man and dog. Dog can smell odors that man 

 cannot, and man can see colors that dog cannot. Black bass 

 may be able to see colors that trout cannot j and while we 

 know from experience that trout do have what affears to 

 be color discrimination, we have no experimental proof that 

 in this case it is not actually a matter of brightness dis- 

 crimination. 



However, to the fisherman this brightness question is aca- 

 demic. To him, it does not matter how the fish tells two 

 colors apart. The main point is that two colors which look 

 different to him look different to the fish also. The fish can 

 tell a blue fly from a red fly. That being the case, it is im- 

 portant for him to have both a blue fly and a red fly, and 

 flies of various other colors and combinations of colors in his 

 book. He has an excellent excuse for stocking up with the 

 various patterns which the tackle store offers, for the fish 

 can tell them apart, and what the fish like one day, or in one 

 stream, they may not like another day, or in another stream. 

 But it is possible that none of this applies to dry flies, or to 

 wet flies fished dry. For when a fly is on the surface, with 

 the strong light behind it, it is doubtful if the fish can see 

 its color. Even man cannot tell the color of a small object 

 held directly against a strong light. It becomes just a black 



