DISTRIBUTION OF EFFORT IX LEARNING IN WHITE RAT 13 



were not being trained, they were allowed the freedom of the 

 square maze during feeding time to keep down body weight and 

 to prevent the accumulation of fat. A day or so between trials 

 had a marked effect on the increase in weight, and the amount 

 of food given had to be carefully watched. Whether this in- 

 crease was due to periods of rest is difficult to say. 



TABLE II 

 Latch Box 



The number of trials and days required to learn the problem 

 and their distribution are found on Plate II. The data here 

 presented are more striking than those previously reported. It 

 shows that still fewer trials were required than with one trial 

 dailv, and a trial everv third dav necessitated the fewest trials. 



