EFFECTS OF THIRST — ALBINO RATS 409 



Jackson ('15) in rats on water only, is probably due to shrinkage 

 of the intervertebral disks. In the tail the shrinkage is evident, 

 though less marked than in the body; thus the tail becomes rela- 

 tively longer in the test rats. 



WEIGHTS OF ORGANS AND SYSTEMS 



Integument 



As shown in table 2, the integument (which includes the skin 

 appendages, external ear, hair, and claws) has in the acute-thirst 

 series apparently decreased in absolute weight from an average of 

 41.9 grams to 28.5 grams, which is a loss of 31.9 per cent in aver- 

 age weight (table 2). In the chronic-thirst series, the corre- 

 sponding decrease is from 40.2 grams to 21.3 grams, a loss of 47 

 per cent. In the rat (Si. 2) on total inanition (table 1) the ap- 

 parent loss in weight of the integument amounts to 42.5 per cent. 



Since these losses are only slightly less than those of the whole 

 body, there is but little change in the relative weight of the integ- 

 ument. Jackson ('15) also found that in rats after inanition with 

 water the loss of weight in the integument is nearly proportional 

 to that of the entire body. (Scheffer, '52, and Falck and Schef- 

 fer, '54, in the dog on dry diet, found the loss in the body weight 

 (20.7 per cent) somewhat less than that in the integument (25 

 to 28 per cent.) 



Skeleton 



The skeleton (tables 1 and 2) was prepared in two ways. Ac- 

 cording to Jackson ('15), the bones, together with the cartilages, 

 periosteum, and ligaments, constitute the 'ligamentous skeleton.' 

 The bones and cartilages, after removal of the periosteum and 

 ligaments by immersion for about one hour in 1 per cent of solu- 

 tion of 'gold dust' (a soap mixture) at 90°C., constitute the 'car- 

 tilaginous skeleton.' The humerus and femur were also weighed 

 fresh, after removal of the periosteum and ligaments, to avoid 

 possible effects of heating in the soap solution. 



As shown in table 2, the ligamentous skeleton of the acute- 

 thirst series shows a loss of 4.3 per cent in average weight, and 



