230 'Journal of Comparative Neurology and Psychology. 



shown alternately or twice in succession is mentioned on p. 257, 

 and the reactions of all three males to similar series are recorded 

 on p. 259. These tests of visual discrimination may be regarded 

 merely as experiments preliminary to the test for visual images. 



One peculiarity in the behavior of the raccoons should be 

 emphasized. When they were discriminating well their eyes were 

 never more than 18 inches from the colored cards, more often 

 within a foot of the cards and still more often within three inches, 

 I. e., the animal took a position with his forepaws on the front 

 board of the card displayer and looked intently for the card to 

 appear. I have never seen the animal look at the card from a 

 distance of several feet and respond to it. This shows the diffi- 

 culty of such discrimination, and it may indicate that the distance 

 for perceiving color or brightness is extremely short. If this be so, 

 the apparent inability to see two glasses when placed 30 inches 

 apart and at a distance of eight feet from the animal is accounted 

 for. 



Discrimination of Sounds. — I endeavored to ascertain the ability 

 of the raccoons to discriminate a high from a low tone and to 

 form the association of being fed at the sound of the high note. 

 The response expected of the raccoon was that he mount the high 

 box to be fed on hearing the food signal. While pure tones should 

 have been used it was, for practical reasons, impossible to do so. 

 I therefore sounded the highest note, Aj, possible with an ordi- 

 nary A French harp or harmonica, then the lowest, A". For the 

 first few trials the hand was extended toward the high box when 

 the food signal was given and the animal fed when he climbed upon 

 the box. When this aid was withdrawn it was found that No. i 

 was practically perfect in responding to the high tone and in refus- 

 ing to respond to the low one. No. 2 had not mastered the asso- 

 ciation. His record after the first few trials in which the hand 

 signal aided him is as follows: 



