Slonaker, Activity of the Rat. 



347 



EXPERIMENT II. 



On the twenty-fifth of February the rats of Experiment I were 

 replaced in stationary cages where they remained for fifteen days, 

 At the end of this time their ages were 70, 100, iii and 306 days, 

 respectively. They were then returned to the revolving cages 

 from which they were taken. This was done primarily to give a 



Revolutions 

 100000^ 



80000 _ 



roooo 



60000 _ 



40000- 



30000- 



20000 _ 



10000_ 



Days 



Fig. 3. Curves of total activity of each rat at different ages as represented by tfie recording clocks 

 for a period of 57 days. The age of each rat at the end of this time was: No. I, 127 days; No. 2, i^l 

 days; No. 3, 168 days; and No. 4, 363 days. 



different series of ages from those of Experiment I and incidentally 

 to test their memory. In the former experiment each rat had 

 learned a way peculiar to itself of reaching the food box, of getting 

 down to the wheel and of entering the nest box. 



