ACTIVITY OF THE ALBINO RAT 



37 



constructed from the data in this table and represent the curves of 

 growth of each of the exercised rats and the control rats respectively. 

 By comparing Figs. 13 and 14 it is readily perceived that 

 the control rats reach a heavier weight and also live longer 

 than those in the revolving cages. This is* especially noticeable 



Weight in Grams 



Fig. 1 3 



Age in Months 



Figure 13. Curves representing the growth and decline of the exercised rats 

 during their lifetime. 



when the males are compared. The exercised and control 

 female rats can be compared only during the first 11 months. 

 About this time No. 11 showed signs of illness. At the age of 

 13 months the malady had developed into a disease common 

 to the white rat. It had been kept in hopes that it would 

 recover, but as it was rapidly declining and there was great 



