138 J. C. DeVOSS and rose ganson 



every stimulus color would be a very different affair from pairing 

 each stimulus color with each of the eighty-nine other Bradley 

 colors. Such procedure in the experiments with these cats would 

 probably have reduced the time required from twenty-eight 

 months to eight. An animal which discriminates the stimulus 

 colors from all those of the same and nearly the same flicker 

 values has a very different type of vision from that of the cat. 



Though the colors have vastly different brightness values for 

 the cat and for the human eye, the brightness equivalents and 

 the flicker-equivalents have intersected many times. A claim 

 that the use of flicker values would not save time must assume 

 that four broad bands of flicker-equivalents on either side of 

 yellow, blue, red, and green respectively might none of them 

 meet, at any point, the brightness values of the animals. Such 

 an assumption is so improbable that in work with colors the 

 neighborhood of the flicker-values of the stimulus colors should 

 be explored first, provided the animal has already made a number 

 of discriminations to become accustomed to the experiment. 



In the experiments with grays, yellow was confused with a 

 gray of the same flicker value. To find the confusion gray for 

 green, we should have had to use a range of four flicker units. 

 With red, blue, and violet flicker values would have been useless 

 for discovering the grays, and "systematic groping" such as we 

 have used in our experiments would be necessary in finding the 

 gray values of those colors for the cats. 



GENERAL REMARKS 



We frequently tried the cats with two glasses lined with the 

 same colored paper, e. g., two yellows, two blues, etc. They 

 failed, so that the assumption that they distinguished by wrinkles 

 or spots on the paper is gratuitous. 



Our records show practically a dead level of uniformity in 

 the responses of each pair of cats. It seems hardly necessary 

 to confirm the work of one cat by giving the same tests to another. 

 It adds a trifle of reliability, but it has added but one new fact 

 to our results, and that of slight importance. 



This uniformity of behavior suggests also a dead level of 

 stupidity. A glimmer of intelligence was observed, for, as already 

 stated, one cat gave good evidence of selecting the food-glass by 

 the position of the thumb-button at the rear of the apparatus, 



