COREELATIVES OF "WATER CONTENT 



213 



perhaps the gates of the depot do not open quite so suddenly and 

 completely (line 00'). Again, there is none of that sort for water. 

 Maybe any tissue that takes up more water than the average for 

 the body (line PP') will be counted as a store. Of that there is 

 evidence, as in the volumes of distribution of SON, T 1824, and VR 

 in figure 114, and in the tissue dilutions of tables 23 and 29, but no 

 one part of the body seems to stand forth as a distinct store. All 

 tissues share the water load in diverse degrees. If AV > AW de- 

 fines a store, is the tissue whose AV < AW an anti-store"? It seems 

 to me that for water, at least, the notion of depots is not substanti- 

 ated sufficiently to use the term ; the increments found in each tissue 

 correspond rather to equilibria of partition. 



-10 -5 +5 +10 



Water Load (Body), AW 



Fig. 115. Diagram of possible relations of water load in a tissue to water load in 

 body. Various lines are described in the text. 



In brief, methods are available for ascertaining by how much 

 a given tissue exceeds in water increment the water increment of 

 the whole body. In this way the distribution of water is found to 

 be uneven. Every analyzable unit and every volume of distribu- 

 tion is a compartment, but no very large ratios of partition appear 

 between the units. 



§ 80. Dilutions of blood and plasma 



The circulating blood may play a peculiar role in recoveries of 

 water content in at least two ways. It is undoubtedly the chief 

 vehicle of redistribution and equilibration among tissues. Is it 

 also a messenger whereby kidneys and other tissues become aware 

 that a load of body water exists % 



Blood and plasma are analyzed in dogs loaded with excess water 



