WATER EXCHANGES OF DOG 



25 



cant, however, that at a given load slightly faster rates follow more 

 recent maximal rates. 



The measurements of water exchanges after sudden establish- 

 ment of water excesses lead to a relation of output to content that 

 is rather uniform, for one is roughly proportional to the other. 

 More exactly, if Rw is rate of water output at load + AW, a is rate 

 of output at no load, and k' is a coefficient of proportion, then 

 Rw-a = k'(AW). In figure 6, a = 0.15% of Bo hour, and k' = 

 0.7/hour. 



+> 



o 



Fig. 6. Eate of total water output (% of Bo/hr.) in relation to total water load 

 (% of Bo). Each point in figure 2 is plotted against the mean load in figure 1, in the 

 corresponding 0.25-hour interval. 



Under the conditions chosen, only urinary losses of water, and 

 losses by no other paths, increase; evaporative losses from skin 

 and from lungs do not, losses do not. Gains by ingestion of water 

 are nil and metabolic production of it is independent of water 

 increment. The net exchange of water (loss — gain) is on the 

 average infinitely increased over that in control conditions, for in 

 them loss equals gain over sufficient periods of time. 



In summary, excess of body water suddenly created in dogs by 

 gastric administration of water leads to rates of water loss typi- 



