ULTIMATE EFFECTS OF INANITION ON SIZE 



111 



As to sex, it appears from the present experiments that in gen- 

 eral the depression in permanent body weight by early inanition 

 is relatively greater in the males than in the females. This is 

 evident in all the charts, 1 to 5. It is also in agreement with 

 the observation by Stewart ('16), who found that in rats held at 

 maintenance by underfeeding from three to ten weeks of age, 

 the females made full recovery upon refeeding, while the males 

 apparently did not. On the other hand, there is no evidence to 

 indicate that the mortality is markedly greater among the males 

 during the inanition period, since the survivors of the experi- 

 ments are about equally distributed according to sex. 



Since the ultimate body weight is affected by the bearing of 

 young (Watson, '06), this factor must be considered. The preg- 

 nancies occurring in each group of the present series are given in 

 the following table: 



It is evident from the table that although opportunity for 

 breeding was equally good in the test rats, their reproductive 

 capacity was very decidedly reduced. This is especially strik- 

 ing in the last two groups, where only one of the twelve test 

 females became pregnant at all ; whereas all of the seven control 

 females became pregnant, bearing a total of sixteen litters. 



Watson ('05) found that the body weight of female albino 

 rats bearing young (three litters) averages about 9 per cent greater 

 than in unmated female controls. This agrees closely with the 

 results of Minot ('91) for guinea-pigs. This might be sufficient 

 to account for the difference between the test and the control 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 30, NO. 1 



