EFFECTS of" THIRST ALBINO RATS 453 



increase, caution must be observed in drawing conclusions, on 

 account of the great variability in the weight of the normal liver 

 (Jackson, '13). 



In the adult rats during thirst the liver loses weight in about 

 the same proportion as the whole body (Kudo, '21). In young 

 rats underfed from three weeks of age the liver is variable, showing 

 a definite increase in weight in the earlier periods, but a decrease 

 later (Jackson, '15 a). Stew^art ('19) found a marked loss in the 

 liver weight of underfed newborn rats. 



PANCREAS 



The pancreas (table 2) in the various test periods shows a pro- 

 gressive increase in average w^eight (15.9 to 46.2 per cent). It 

 may be noted that the average weight of the pancreas in my con- 

 trols (0.1389 gram) is considerably below the corresponding 

 weight found by Hatai ('18) (0.206 gram) ; but, as Hatai remarks, 

 it is difficult to dissect out the gland with uniform accuracy. 



In adult rats a decrease in weight of the pancreas during thirst 

 is relatively much greater than that of the whole body. Thus 

 the loss in the weight of the pancreas resembles that of the salivary 

 glands. 



STOMACH AND INTESTINES 



The stomach and intestines were separated from mesentery and 

 pancreas. The digestive tube with contents (table 2) shows a 

 progressive increase in average weight, varying from 1.4 to 30.6 

 per cent. The increase is not significant until after six weeks. 

 The data for the empty stomach and intestines show a very simi- 

 lar progressive increase in average weight, varying from 4.6 to 

 34.6 per cent. Thus both the alimentary canal and the intestinal 

 contents appear to increase in weight, especially in the thirst 

 experiments extending beyond six weeks in length. The intesti- 

 nal contents in the test rats are watery or mucous in character in 

 the small intestine, becoming usually very hard in the fecal mate- 

 rial of the large intestine. 



In rats underfed from three weeks of age Jackson ('15 a) like- 

 wise found an increase in the weight of the intestinal canal (plus 



