CORRELATIVES OF WATER CONTENT AND EXCHANGES 



271 



Maximal intake rates equal 5 to 17 times the turnover rates (= aug- 

 mentation ratios). 



These correlations might be used to predict by interpolation the 

 probable rates of water exchange in other species. I do not recom- 

 mend prediction as a substitute for measurements of them. It is 

 apparent that time of recovery from water load is independent of 

 body size ; rat and man remove loads equally rapidly. 



Data upon water exchange in other classes and phyla of ter- 

 restrial organisms apparently are not available, with a few excep- 



ON 



o 







7 



12 3 4 5 6 



~^ Log Gm. Body Weight 



Fig. 139. Eate of urinary water output in relation to body weight among diverse 

 species of mammals. Ordinary rates are in water balance (from table 28): IIto = 

 0.0064 Bo- 82, Maximal rates are during continued forced administration of water by 

 stomach (from table 13): E„ai = 0.26 Bo.ts. 



tions as pigeon (Falck and Scheffer, 1854a) and chicken (Korr; 

 Hester ei al., '40). Among aquatic animals (fig. 140) rates of 

 turnover are proportional to B°'^^ and maximal rates to B°-^^. This 

 confirms the more approximate conclusion of Putter ( '26) that 

 water exchanges are proportional to body surface area. At equal 

 body weights the turnover rates of these aquatic animals are 

 roughly identical with those of small mammals of figure 138. 



A rule enunciated by Eichet (see Morgulis, '23, p. 91) is that the 

 intensity of vital functions depends directly upon the size of the 



