122 C. M. JACKSON AND C. A. STEWART 



The thyroid gland,' which was found somewhat variable in its 

 weight at the end of the inanition periods and on refeeding to a 

 body weight of 25 to 75 grams, appears hkewise somewhat 

 inconstant in the present series (table 2) refed to maximum 

 body weight. The results do not warrant any more definite 

 conclusion. 



The thymus, which undergoes a marked loss of weight during 

 'hunger involution/ was found still subnormal upon refeeding to 

 a body weight of 25 to 75 grams (Jackson and Stewart, '19). 

 The subnormal weight still persists in three groups of the present 

 series, refed to maximum body weight (table 2). In one of the 

 groups, however, there is a remarkable overweight of 85.7 per 

 cent, probably due to experimental error in removing fat along 

 with the thymus. 



The hypophysis has been found by Hatai to show a sexual 

 difference in weight, therefore the data for this gland are listed 

 separately b}^ sex in table 2. In most cases (excepting in the 

 male on long underfeeding) it was found nearly normal at the 

 end of the underfeeding periods, and on refeeding to a body weight 

 of 25 to 75 grams. In the present series, refed to maximum 

 body weight, it is more or less subnormal in all but one group 

 (table 2), which shows a slight overweight (+8.2 per cent). 

 Jackson ('17) found that in young rats refed four weeks or more 

 after inanition the hypophysis has for the most part recovered 

 its normal histological structure, although atrophic areas may 

 persist for indefinite periods. 



The pineal body was found irregular in weight in the underfed 

 rats on refeeding to body weight of 25 to 75 grams. Likewise 

 in the present series (table 2) , it shows an apparent overweight in 

 the first two groups, but a decidedly subnormal weight in the 

 third. On account of the small size of the gland, no definite 

 conclusion can be drawn from the few observations. 



The heart shows a tendency to increase in weight in the earlier 

 underfeeding periods, but loses weight later. It was usually 

 found nearly normal in the rats refed to a body weight of 25 to 75 

 grams. In the present series, refed to maximum body weight, 

 the heart shows a tendency to hypertrophy, which is distinct in 



