14 HELEN B. HUBBERT 



noticeable change in the behavior of the rats, marked disturb- 

 ance resulted from a delay of four or five hours. 



In general, the behavior of individuals of each group on first 

 entering the maze was the same. The fats showed great hesi- 

 tancy in leaving the starting box, returned to it frequently 

 after finally entering the maze proper and endeavored to push 

 up the sliding door; they were slow to leave a familiar alley 

 for one unexplored, became excited when a stop was encoun- 

 tered, trying repeatedly to push it aside or to gnaw through 

 the mesh top, and made frequent efforts to escape from the 

 maze. Departure from this type of behavior was noticed among 

 the very old rats and the very young ones. Many of the former 

 evidenced no excitement whatever, often sleeping for several 

 minutes between period of activity, while the latter were far 

 more active than the rats of any other group, and showed no 

 hesitancy in entering unfamiliar portions of the maze. 



The time usually decreased very rapidly, the distance less 

 so, during the first three or four trials. For example, on its 

 first trial, rat 34 of the three hundred day group required eleven 

 minutes and forty seconds to reach the food, and the distance 

 covered was forty-nine and six tenths meters. On its second 

 trial, seven minutes six seconds were required, and the distance 

 run was thirty and nine tenths meters ; at the fourth trial, success 

 was attained after one minute nineteen seconds, the pathway 

 traversed measuring ten and two tenths meters, while for the 

 sixth trial, the time record was only forty-nine seconds, the 

 distance eight and six tenths meters. By the tenth or fifteenth 

 trial, the decrease in both time and distance had become much 

 more gradual, and continued so until the problem was learned. 

 The rat referred to above, required on the fifteenth trial, twenty- 

 four seconds, and ran seven and two tenths meters; on the 

 thirtieth trial the trip occupied fourteen seconds, and covered 

 five and six tenths meters. This particular animal completed 

 the problem at the sixty-sixth trial, when the time record was 

 seven and two tenths seconds, and the distance record four and 

 five tenths meters, which, it will be remembered, constitutes 

 a perfect run. 



The data set forth above may be conveniently tabulated 

 thus: 



