452 TOKUYASU KUDO 



LUNGS 



The lung infections frequently found in older rats rarely occur 

 before the age of ten weeks (Jackson, '15 a) and did not occur in 

 in the rats shown in tables 1 and 2. The average weight of the 

 lungs in the test groups shows slight changes, varying from —9.5 

 to +3.5 per cent. These changes are usually in the same direc- 

 tion as the differences in average body weight, however, and are 

 too small to be significant. It is therefore evident that there is 

 but slight if any change in the weight of the lungs during the pres- 

 ent thirst experiments. 



During thirst in adult rats the percentage loss in the weight of 

 the lungs appears slightly greater than that of the whole body 

 (Kudo, '21). In young rats held at constant body weight by 

 underfeeding, Jackson ('15 a) found a slight decrease in the early 

 periods, but not in the later. There is no appreciable increase 

 in the lungs of the underfed newborn rats (Stewart, '19). 



SALIVARY GLANDS 



Parotid glands. The parotid glands (table 2) show a marked 

 decrease in average weight, varying from 43.7 to 59.6 per cent in 

 the various test groups. This loss apparently occurs early and 

 remains fairly uniform throughout the various test periods. In 

 adult albino rats during thirst, both in acute and chronic, the per- 

 centage loss in weight of the parotid glands is likewise much larger 

 than that of the entire body (Kudo, '21). 



Suhrnaxillary glands. A striking decrease in weight similar 

 to that of the parotid glands is apparent in the submaxillary 

 glands (table 2) in all except the first test group, where the loss 

 (24.9 per cent) is somewhat smaller. In adult albino rats during 

 thirst, both acute and chronic, the submaxillary glands likewise 

 decrease in weight relatively much more than does the body as a 

 whole (Kudo, '21). 



LIVER 



The liver shows somewhat irregular increases in average 

 weight (table 2), varying from 5.8 to 33.5 per cent in the different 

 test periods. While the liver thus shows a definite tendency to 



