34 The Lije Story of the Fish 



pigmentation existing in most fishes, which determines the 

 color pattern at any moment.^ 



It was for many years taken for granted that these color 

 changes were for the most part concerned with the business 

 of protective coloring. Then there appeared upon the scene 

 the aforementioned gentlemen who refuse to believe in pro- 

 tective coloration. Exemplifying the fact that all people, even 

 scientists, go to extremes, they are in revulsion against the 

 generation of naturalists who talked about "our little feath- 

 ered friends" and "the finny denizens of the deep," who 

 saw in everything from the shell of the oyster to the skull of 

 man the workings of an all-wise and all-foreseeing provi- 

 dence. These upholders of the opposite extreme not only 

 snort with rage at anything savoring of the teleological, but 

 they object to applying in any way man's standards of values 

 or his sense of relationships to any of the workings of nature. 

 They seem to lean over backward, and, in fear of being con- 

 taminated by human ideas in the interpretation of nature, to 

 deny what appear, in the light of common sense, to be the 

 most obvious explanations. 



These people denied the existence of protective coloration. 

 They refused to believe that the fish's color changes had any 

 connection with its background, and some of them even re- 

 fused to believe that color changes took place in fish at all, 

 arguing that what appeared to be such were optical illusions 

 on the part of the observer. It was not long before first one 

 laboratory, and then another, was working to refute them, 

 and each, because of the facility with which these animals 

 change color, chose members of the flounder family for 

 experimentation. Flounders were transferred back and forth 

 from one kind of background to another until they must 



^ The blutf and green colors seen In fish are g-enerally due to the reflec- 

 tions and interferences of light by the colorless surfaces of the guanin 

 crystals and the scales, acting in conjunction with the different pigment 

 combinations. 



