The Sense of Sight : Color Vision 145 



brightness, and that they continued to do so for the same 

 reason. In other words, their behavior indicates that the 

 brightness check tests were valueless because not enough 

 allowance had been made for the possible differences between 

 the vision of mouse and man. 



TABLE 19 

 LIGHT BLUE-ORANGE AND DARK BLUE-RED TESTS 



If only the final result, of my experiments with the dancer 

 and the conclusions to which they lead were of interest, all 

 of this description of experiments which served merely to 

 clear the ground and thus make possible crucial tests might 

 be omitted. It has seemed to me, however, that the history 

 of the investigation is valuable, and I am therefore presenting 

 the evolution of my methods step by step. To be sure, not 

 every detail of this process can be mentioned, and only a 

 few of the individual results can be stated, but my purpose 

 will have been fulfilled if I succeed in showing how one 

 method of experimentation pointed the way to another, and 



