256 'Journal of Comparative Neurology and Psychology. 



just disappeared with one now present. Either this or else the 

 animal must keep track of the number of times the colors are 

 shown, going up every other time when the colors appear alter- 

 nately, every third and fourth time when they appear by twos , etc. 

 This second explanation violates the law of parsimony, of course, 

 and was eliminated by the fact that I secured series of perfect 

 reactions when the colors were shown at random. When I changed 

 for the first time from alternate showing to twos, or from twos to 

 threes, there resulted confusion and errors quite sufficient, I think, 

 to show that the animals distinguish one movement from two or 

 two from three (a species of counting). As this was of no avail 

 when the colors were shown at random, I also believe that the 

 animal must have retained some sort of image or visual impression 

 of the absent color and reacted to it. The experiment now took 

 a form which shows this more clearly. Spontaneously several of 

 the raccoons had been clawing the "no-food" card down and 

 sometimes they clawed the "food" card up. Finally, all but No. 4 

 became fairly proficient in this. I quote one of the records made 

 by No. I (Jack), after much training. 



TABLE X. 



Trial. Green. Red. Remarks. 



1 * — He clawed green up and was fed 



2 * — He clawed green up and was fed 



3 * — He clawed green up and was fed 



4 * ■ — He clawed green up and was fed 



5 * — He clawed green up and was fed 



6 * — Put red up, looked at it, then put it down, then put green 



up. 



7 * — Put red up, then put green up. 



8 * — Put red up, then put it down. 



9 * — Leaving red up, he put green up. 



10 * — Put red up and left it up, then put green up. 



11 * — Put red up, then down, then put green up. 



li * — Put red up and left it up, then put green up. 



— Put red up and left it up, then put green up. 



— Put red up, then down, then put green up. 



— Put green up. 



— Put red up and left it up, then put green up. 



— Put red up and left it up, then put green up. 



— Red up, then down, then green up. 



■ — Put red up then green up. 



— Put red up and down twice, then green up. 



— Green up. 



— Green up. 



— Red up, then down, then green up. 



— Put green up. 



— Put green up. 



