302 HENRY FOSTER ADAMS 



one rat on one trip. All of the other records were considerably 

 slower. With another set of blind rats which were used mme- 

 diately after this set, all of the group made the trip in 10 seconds 

 or under consistently. The time spent in getting to the food 

 box by rat 3, which learned the maze perfectly, is quite irreg- 

 ular. It varies from 2.1 1 minutes to .30 minutes for trips with- 

 out error. 



Another peculiarity is the slowness with which the two sec- 

 cessful rats learned the maze. The second set of blind rats, 

 used in the same maze, were able to go five successive times 

 without error with an average of 20 trips, the slowest one having 

 learned it on the 23rd trial, the best on the 17th. Applying the 

 same criterion to the first set of blind rats, we find that the 

 better of the two had learned the maze on the 49th trial, the 

 other on the 63rd. 



To save time in the number of days spent in the learning 

 process, I ran the rats twice a day from the 25th to the 62nd 

 trip. This seemed to affect the two rats which did learn the 

 maze quite differently. Rat 3 continually made more errors 

 on the first trial than on the second, often going the second 

 time without error. Rat 7, on the other hand, made the first 

 trial quite successfully, generally without error, but went all 

 to pieces on the second trip, sometimes making as many as 36 

 errors. 



After finishing with the animals, we sent them to the Depart- 

 ment of Neurology, for a post-mortem examination. A gross 

 examination disclosed no defects whatsoever. 



