A SET OF BLIND WHITE RATS WHICH COULD 

 NOT LEARN THE MAZE 



HENRY FOSTER ADAMS 



During a series of experiments performed at the University 

 of Chicago during the years iqio and 1911, the writer found 

 a set of three blind rats which could not, or at least did not, learn 

 the maze during a total of 182 trials. As no comment upon a 

 phenomenon of like nature has come under my observation, it 

 seemed worth while to mention it. 



Originally there were seven rats, six females and one male, 

 all mature and healthy. They were blinded by removing the 

 eye-ball. All recovered promptly and were set to work to learn 

 the maze. 



During the course of the experiment, two of the rats died, 

 so their records are not included. The disease which carried 

 them off is, I believe, a relatively common one among white 

 and black and white rats. First there is a sluggishness, a loss 

 of appetite and general listlessness. This is followed in a day 

 or two by other symptoms, the most prominent of which is a 

 persistent twisting of the neck, so that the head is turned side- 

 ways in an abnormal manner. The head is turned more and 

 more from day to day. Finally the animal finds it difficult to 

 stand, is almost incapable of walking and, if it attempts to do 

 so, often rolls over and over on the floor of the cage. Since 

 the symptoms are somewhat similar to those following semi- 

 circular canal disturbances, it is thought by some that the 

 disease is due to a "cold" which has settled in those organs. 

 So far as I know, this is mere supposition. The disease is gen- 

 erally fatal, though there have been some cases in which the 

 animal so afflicted has recovered. 



One of the rats in this set which finally learned the maze 

 was finally carried off by this trouble. During the first stages 

 of the disease, it was still run in the maze. The animal had 

 "forgotten" the labyrinth entirely. Not only that, but it ran 

 at full speed ahead, bumping into blind alleys, partitions and 

 the like. Whenever it got to its feet, it ran in the direction 



300 



