COLOR BLINDNESS OF CATS 127 



had been discriminated from yellow by one cat only with con- 

 siderable difficulty and after a long period of training. We then 

 sought to find a gray, of a texture similar to that of the yellow 

 paper and of an intensity near to that of the grays mentioned 

 above. We found a gray, an ordinary writing paper of rather 

 dull finish, which fulfilled these conditions. We shall refer to 

 it as Gray 1-2, since its flicker equivalent was mid-way between 

 grays 1 and 2. This gray was confused with the yellow, as the 

 following tables show. 



Though very extensive tests were made, we could find no 

 gray paper which was not very promptly discriminated from 

 blue. It occured to us that a very considerable range of gray 

 cambrics is supplied by the dry goods stores. As a last resort 

 we turned to trying these. Most of them were promptly dis- 

 criminated from the blue, but finally a dark gray shade (F. E. 

 —44-45) was found which neither Cat 3 nor Cat 5 could dis- 

 criminate from the Bradley blue. Meanwhile, we had found a 

 blue cambric which these cats confused with Bradley blue. For 

 the sake of still further evidence we paired this blue cambric 

 with the gray cambric. The two were, in turn, confused. 



Again, in using violet as a stimulus color it was found to be 

 confused only with a gray cambric of F. E. — 48. 



The following tables record the confusions of yellow, blue, 

 red, green, and violet with grays. 



Confusion of Yellow with Gray 1-2 



TABLE V (A) 

 Confusion of Blue Paper with Gray Cambric 



TABLE V (B) 

 Confusion of Blue Paper with Blue Cambric 



