25 



their vibrisaae. Theae rats were weaned at eighteen days, and 

 were fed in the maze for five daya preceding the experinent, 

 the forty-five and thirty minute feeding perioda being omitted. 

 For the first day or tvvo after starting the problem, they were 

 allowed to eat for six or seven minutes instead of live miuutes 

 at the end of each day's work, since it developed that a short- 

 er ration had a weakening effect on animals so young. The lit- 

 tle rats %ere exceedingly active, and on entering the maze ran 

 so rapidly that it was very difficult, but never impossible, 

 to trace their movements. For the most part they showed great 

 eagerness to escape from the starting box, some even acquiring 

 the habit of lifting the door partway with the nose, and as a 

 rule they had no hesitancy in entering unexplored portions of 

 the naze, in this resject differing from most of the rats in 

 this experiment. The error of circling the food box occurred 

 more often with rats of this group than Aith those of any 

 other, the explanation being, perhaps, that in their over- 

 eagerneas to reach the food they acquired such momeatum than 

 they ran past the entrance to the food box. 



Twenty-seven rats were experimented with at this age, 

 eleven males and sixteen females, eight straias being repreaent- 

 ed,as fellows: 



Wl! ,/^j^ Y f C F )z/,^u G Jy/^'/f AL ^'4/4 XL ^J's/n Y L fo/,^ Z 7; '//m T.Y i'M Al 1 



Males C 2111 51 2 11 



Females 2 1113 55 16 



Total 2 3 2 2 4 8 4 2 2 7 



