GROWTH AFTER INANITION FOR VARIOUS PERIODS. 4! 



normal as compared with the weight in a control killed at the 

 end of the fasting period. 



Salkind ('15) observed that a minimum of at least one week of 

 refeeding was necessary to restore the normal lymphoid structure 

 of the thymus in rats suffering severe starvation for two days. 



14. Heart (Table V}. 



The heart at the end of the maintenance period was 15.6 and 

 34.1 per cent, below Donaldson's norm of weight. Jackson 

 ('15), however, noted practically no change in the weight of the 

 heart during maintenance. The discrepancy in my rats may 

 possibly be due either to normal variation or to experimental error. 



At the end of the various refeeding periods the heart (with one 

 exception) was heavier than Donaldson's norm, the excess varying 

 from 3.0 to 22.9 per cent. At the end of four weeks of refeeding, 

 the weight of the heart in the test females exceeded the Wistar 

 norm 17. 6 per cent, while the controls exceeded it by 17.0 per cent. 

 The heart therefore appears practically normal in weight at 

 sixteen weeks in the refed rats as compared with the controls. 

 This was also true for the adult animals. 



In general, therefore, it may be concluded that the heart was 

 probably nearly normal in the test rats throughout refeeding, 

 although it appears relatively heavy (in comparison with Donald- 

 son's norm) during the earlier weeks of refeeding. 



15. Lungs (Table V.}. 



The weight of the lungs was 17.1 and 27.0 per cent, below the 

 Wistar norm at the end of nine weeks of maintenance, indicating a 

 decrease in size during that period. Jackson ('15) found a loss 

 of about 15 per cent, during seven weeks of maintenance. The 

 lungs were also somewhat below the norm during the first week 

 of refeeding, but somewhat above thereafter. The excess was 

 especially marked in the rats refed four weeks (42.0 to 69.3 

 per cent.), but the controls also showed an excess weight of 44.1 

 per cent. This excess might be due to an over-compensation of 

 growth, or merely to variability from other causes (possibly 

 pathological, due to slight pulmonary infection). In the adult 

 rats the lungs were smaller than the norm except in the case of 



