426 TOKUYASU KUDO 



the entire body. In three organs in this last group there is 

 apparently a slight gain. To make the comparison of the results 

 in this manner, the data have been arranged as in table 3. 



In addition to the organs listed in table 3, the few observations 

 on the bladder and aorta (table 2) during thirst, both acute and 

 chronic, indicate that these organs suffer a marked loss in weight. 



If we compare the changes in weight of the organs or systems 

 during acute thirst with those during chronic thirst, it appears 

 that they are, on the whole, very similar, making due allowance 

 for the greater loss of body weight in the chronic-thirst series. 

 In a few organs, however, there is a considerable difference. 

 For example, the testis, epididymis, and musculature suffer rela- 

 tively a much heavier loss in weight in the chronic-thirst series 

 than in the acute-thirst series. 



On the whole, however, it is evident that the results in the two 

 series are remarkably similar to each other, and also (especially 

 the chronic series) to those obtained in the rat after total 

 inanition. 



A further study of the data for the acute-thirst series (tables 

 2 and 3) shows that the large losses in weight are suffered by 'the 

 remainder' (composed mainly of fat, lymphatic glands, etc.), the 

 integmiient (carrying fat), the visceral group (highly cellular), and 

 the musculature, parts which taken together represent about 80 

 per cent of the gross weight of the control rats. It is evident 

 from this that variations in the loss of other parts or organs will 

 modify but slightly the total losses observed. 



Comparing my results on thirst with the changes in weight of 

 organs and systems of the albino rat found by Jackson ('15) dur- 

 ing inanition with water, there appears a surprising degree of 

 similarity. There are, of course, some organs which are more or 

 less different. For instance, the thyroid gland, suprarenals, and 

 intestinal tract apparently suffer a greater loss during thirst than 

 during inanition with water; but it is somewhat doubtful whether 

 the difference is due entirely to the difference in diet. The 

 changes in the chronic series, either on a dry diet or with water, 

 might possibly be due in part to lack of vitamines in the diet; 

 but this could hardly be the case in the acute series, where the 



