34 



PHYSIOLOGICAL REGULATIONS 



is concerned in adjustments (recoveries) by water loss. Only two 

 paths of gain are recognized: ingestive and oxidative (metabolic). 

 Evidently oxidative formation of water is not a means of restoring 

 water content after a deficit; drinking alone is responsible for 

 adjustments by water gain. 



The ratio of maximal rate to minimal rate of total exchange 

 (or of some distinguishable path of exchange) is a convenient 

 measure of adaptability with respect to this function. It may be 

 termed the ratio of modification. This ratio amounts in the dog, 

 reading values from figure 13, to 3.3/0.17 



5 



19 for total loss, 100 



Rate of Tota 



Fig. 15. Eate of total water gain (% of Bo/hour) in relation to total water loss 

 (% of Bo/hour). The curve is transformed from figure 13, representing the first one 

 hour of recovery of water content. Similar data of figure 29 below, representing rates in 

 steady loads, fall on approximately the same curve. The dash diagonal line indicates 

 equality of gain and loss. 



for total gain, 103 for urinary loss, etc. This indicates the enor- 

 mous range of rates over which the exchanges operate, each rate 

 appearing under circumstances appropriate to the equilibration as 

 a whole. 



The quantitative, contrasts in rates of exchange are further 

 expressed in figure 15. High rates of gain are found only with 

 low rates of loss, and vice versa. Water balance occurs only at 

 relatively low rates of both. The mutual exclusion of high rates 

 of activity has often been recognized qualitatively in the concept 



