[MILLS] COMPARATIVE PHYSIOLOGY AND PSYCHOLOGY 299 



so altered the position of the uncovering paper that he could see the con- 

 tents of the box (meat), which he at once seized and ate. 



May 5th: Accidental exposure of the contents of the box; experi- 

 ment not successful. 



May 7th: The red box was placed on the left. As soon as the 

 apparatus was placed in the cage, he lifted the red paper up somewhat, 

 peered imdemeath in a most suggestive and amusing way, and lifted 

 out the food very gingerly. 



May 8th : The red box was placed to the right. Though he 

 looked plainly to this box first, he took the blue paper off the blue 

 box and began to tear it up. A few minutes later he knocked the 

 red paper off accidentally, saw the meat and ate it. 



May 9th: The red box placed to the left. His attention was 

 plainly drawn to the red box and held there. Soon he lifted up the 

 paper and seized the meat in the box. 



May 10th: Eed box placed to the right. His attention was, as 

 on the day before, distinctly drawn to the red box and on this occasion 

 he walked from the left over the blue hox and lifted the paper from 

 the red box and at once ate the meat from it. 



May 11th : The same experiment as on the day previous and with 

 similar results. 



May 14th: Eed box placed to the left. He again walked over 

 the blue box, pecked at the red paper covering the other and secured 

 the meat in it. 



May 15th: The experiment of May 14th repeated and with the 

 same result. 



Owing to accident a couple of later experiments were inconclusive, 

 and to my great regret the bird died on May 19th, 



Post Mortem examination showed no special Isesion as cause for death, 

 and as his strength had been obviously failing, while his activity remained 

 as great as ever, I am convinced death was due solely to exhaustion. 

 So far, however, as this particular point was concerned, the experiments 

 were sufficient to make the case clear. 



It was plain to both the laboratory attendant, who looked after 

 the crow from the first, and to myself, that, from May 9th, at latest, 

 i.e., after five trials, some sort of firm mental association has been 

 formed largely through the colour sense as the chief initiating stimu- 

 lus. One could not but feel convinced of the great distance intervening 

 psychically between such a bird as a gull and a crow. 



I was also impressed as a result of these observations as carried 

 out on the three birds, whose life history in the laboratory has been 

 given in outline, of the danger of drawing conclusions from even an 



