48 CHESTER A. STEWART. 



of the body weight in the male and females respectively, as 

 compared with .00116 per cent, in the controls of the same age. 



In the adult rats, the relative weight of the pineal body was 

 .00042 per cent, in the control males and .00050 per cent, in the 

 test males. For the females, the relative weight was .00066 

 per cent, in the controls and .00067 per cent, in the test animals. 



The differences in relative weight between males and females 

 are probably due to the difference in body weight. There is 

 no indication of a sexual difference in animals of the same body 

 weight (such as has been found in the suprarenals, hypophysis 

 and parathyroids), which is in accord with the conclusion of 

 E. R. Hoskins (at present unpublished) based upon data collected 

 in this laboratory. 



It appears therefore that the pineal body was of normal 

 weight in the rats refed four weeks and one year. 



CONCLUSION. 



The present experiments have shown that the marked tendency 

 of the body as a whole in young rats to recover its weight after a 

 period of maintenance is likewise characteristic of the various 

 organs and parts. The abnormal proportions produced by 

 underfeeding rapidly disappear upon generous refeeding, so that 

 practically the normal relations are restored in most cases within 







four weeks. This readjustment evidently involves a modi- 

 fication of the growth curves of many of the various organs and 

 parts of the body during the early refeeding periods. Thus 

 those organs and parts which lost weight during maintenance 

 grow more rapidly than the body as a whole, whereas those which 

 gained weight during the maintenance period show a tendency 

 to lag behind until the normal balance is restored. 



SUMMARY. 



The more important results of the present investigation may 

 be summarized as follows : 



The average daily gain in weight of the young rats refed after 

 being held at constant body weight for short repeated periods 

 was somewhat higher than that of the controls. This enabled 

 the test rats to make up lost time and to overtake the controls, 

 but not to exceed them in body weight. 



