Body Covering 37 



discovery, and he might well permit himself to say, "Nat- 

 urally the fish's eyes play an important part in his color 

 adaptation. What else would you expect?" But to those 

 scientists who believe that things are never what they seem 

 it was a blow, for they had maintained that the color changes 

 were caused by the action of light on the pigment cells in the 

 skin, and that the eyes had little or nothing to do with it. 



It was also found that with either eye alone, color adapta- 

 tion took place just as well as with both 5 in other words, 

 each eye acted on all the chromatophores of the body, and 

 this was confirmed by the finding that if a fish were held 

 right on the dividing line between white and black, so that 

 one eye was on the black side and one on the white, it assumed 

 a uniform gray color. The chromatophores, acted on equally 

 by each eye, were held in a state of balance. However, not 

 all species are like these flat-fishes. Trout with one eye put 

 out of action will show color changes only on one side. 



There still remained one refuge for the die-hards. What 

 proof is there, they asked, that the eyes of other animals see 

 the same things that ours do? What right have we to assume 

 that just because a certain animal pattern is invisible against 

 a certain background to us, it is also invisible to that animal's 

 enemies? Does protective coloration protect? 



This point is not as far-fetched as it may seem, because the 

 difference between the machinery of our eyes and that of the 

 lower animals is considerable, as will appear in a later chap- 

 ter. Moreover, it is a difficult point to controvert, for how 

 is anyone ever to find out what the world looks like to any 

 other person, especially when that other person is a bird or a 

 fish? 



Theoretical arguments went back and forth for years with- 

 out breaking the stalemate, until one of the leading ex- 

 ponents in the earlier flounder work hit upon a series of 

 experiments of a simplicity nothing short of beautiful. In 



