454 TOKUYASU KUDO 



mesentery and pancreas), which continued up to the age of six 

 weeks, but appeared to decrease later. In adult ablino rats dur- 

 ing thirst there is a marked decrease (relatively slightly less than 

 that of the entire body) in the weight of the stomach and intes- 

 tines (Kudo, '21). 



KIDXEYS 



The kidneys (table 2) in the test groups show a marked appar- 

 ent increase in average weight, progressing from 35 to 65.3 per 

 cent in the first four groups, but decreasing to a gain of only 48.4 

 per cent in the longest test (nine to thirteen weeks) . It is possi- 

 ble, however, that the large apparent increase may be due in part 

 to an abnormally low kidney weight in my controls, which is 

 somewhat below the normals of Jackson ('15 a) and Donaldson 

 ('15). In young rats underfed beginning at three weeks of age 

 Jackson ('15 a) found a slight increase in the weight of the kidney, 

 but little or no change at later periods. Stewart ('19) found a 

 great increase (90 per cent) in the kidney weight of underfed new- 

 born rats. 



In adult rats during acute and chronic thirst the kidneys lose 

 in weight relatively slightly less than the body as a whole (Kudo, 

 '20). 



TESTES 



The average net body weights of the males in the various groups 

 of table 2 are as follows : controls (2), 26.6 grams; 1-2 weeks (2), 

 26.7 grams; 3-4 weeks (6), 22.4 grams; 5-6 weeks (3), 25.8 grams; 

 7-8 weeks (1), 23.1. It is thus evident that the average body 

 weights of the various test groups differ somewhat from the con- 

 trols, which partly accounts for the greater apparent losses in the 

 groups at three to four weeks and seven to eight weeks. Making 

 allowance for this difference in body weight, the tests would show 

 an average decrease of something over 30 per cent. 



On the other hand, Jackson ('15 a) found an apparent increase 

 of 34 per cent in the weight of the testis in rats underfed beginning 

 at three weeks of age, and Stewart ('19) obtained an enormous 

 increase (average 374 per cent) in the testes of newborn rats held 

 at maintenance by underfeeding for about sixteen days. 



