8o THE DRY-FLY MAN'S HANDBOOK 



placing on record here my own views of the colour 

 question, views which I am told are shared by many 

 others. I am not, and never have been, a believer in 

 the theory advanced some years since by Sir Herbert 

 Maxwell that fish are colour-blind. In justice to him 

 it should be said that he himself has since to a g-reat 

 degree recanted some of the opinions he advanced on 

 the subject.* While believing that the trout or gray- 

 ling in the water can, to some extent, differentiate 

 tones and colours, I do not think that the presence or 

 absence, for example, of a tinge of brown in the body 

 of a female iron-blue spinner, would suffice to account 

 for a trout which is feeding on the natural insect {Da'itis 

 pumilus) represented by this pattern fastening to the 

 one with this brown shade, and coming short to one 

 dressed with claret body like the old-fashioned pattern. 

 At the same time there are occasions when, and places 

 where, one is almost tempted to think that the colour 

 perception of the Salmonidse is developed to the 

 highest degree. Every fisherman, however, who has 



* Sir Herbert Maxwell takes exception to this, and writes in the " Pall 

 Mall Gazette " of March 30th, 191 1 ; " First, I have never advanced the 

 theory that fish are colour-blind ; secondly, I have never recanted any 

 opinion previously expressed on the subject." He then suggests for 

 observation and experiment three alternative hypotheses: "(i) That 

 salmon and trout are insensible of colour. (2) That like human beings 

 they cannot nicely distinguish colour in an object presented to them 

 between their eyes and the light, which is the case with a fly, natural or 

 artificial, on or near the surface of the water. (3) That if they have the 

 power of distinguishing colour in flies so presented to them, they show 

 indifference to it, provided that the shape and movement of the lure is 

 life-like, and as regards trout provided the shade of hue (light or dark) 

 approximates to that of the natural insect." 



