46 



PHYSIOLOGICAL REGULATIONS 



ascertained only over periods lasting several hours. Many of their 

 rates are higher than in figure 26, the maximum being 3.4% of 

 Bo/hour. But whether they are still linearly proportional to water 

 load cannot be ascertained; I infer they are not. Certain of the 

 data given by Harding and Harris indicate that in some individuals 

 low rates of water output accompany large loads, as though under 

 stress of continued administrations of large amounts of water 

 (10% of Bo/hour), water automatically accumulates (up to +20% 

 of Bo) in individuals that excrete slowly. 



Descriptive physiology may proceed in the correlation of quan- 

 tities without inquiring whether the hypophysis, or any other 

 organ, regularly influences the excretion of water. Very often 







+1 



+2 +3 +4 +5 



5en3ible Water Load 



+6 



+7 



Fig. 27. Eate of urinary water output (% of Bo/hr.) in relation to sensible water 

 load (% of Bo). The data are from figures 24 and 22, water being given by stomach 

 every 0.25 hours for ten periods up to maximal load. 



such an organ is regarded as a dictator of water exchanges. From 

 the relations shown above it is evident that the dictator, if such 

 there be, precisely grades the exchange to the load. Whether that 

 fact robs the dictator of his title, is of little moment. To know in 

 what anatomical part, if any, the grading of exchange to load is 

 managed, is a project for research, but is not required for the 

 present description of water maintenance. For, the quantitative 

 relations shown in equilibration diagrams are explanations of 

 water regulation to the same degree as relations of any other kind 

 that have been discovered. 



What has been shown is that repeated gastric administrations 

 of water at brief intervals ultimately produce a stationary rate of 

 water loss. At diverse rates of administration, the resulting losses 

 are proportional to water loads. The same proportionality con- 



