WATER RELATIONS OF MAN 107 



large as C.Y. ± 80, that is still a standard. The number of states 

 in which water contents and exchanges are altered also is large. 

 In practice it may be easier to "force fluids" at random than to 

 attempt the differentiation of those states. In theory the intimate 

 connection of water with such a large number of states is of out- 

 standing consequence. 



§ 34. Diverse types of water load 

 A few studies that furnish portions of equilibration diagrams 

 under conditions other than those used above may be indicated. 



(1) Water in excess is ingested with particular quantities of 

 four different foods (data of Petrilli) . The subsequent elimination 

 of the water is less than without food, and lasts longer. Anyone 

 can imagine where some of the water goes and where some of the 

 delay may occur. 



(2) "Water deficits are created by physical exercise instead of 

 by dietary privation. The deficit is produced in 1 or 2 hours in- 

 stead of in 1 or 2 days, therefore. Subsequent initial ingestions 

 (points D, fig. 59) happen to be in the range of those established 

 for privation alone. 



(3) Water deficits follow moderate exertion in very hot atmos- 

 pheres during 1 to 3 hours. Subsequent drinking is at mean rates 

 somewhat higher (B, fig. 58) than in another state (C), and the 

 rates differ significantly. The difference is chiefly at small deficits 

 (fig. 59). It is possible that the excess of heat content added itself 

 to the deficit of water content in arousing ingestion. 



(4) In warm environments the total water losses in balance are 

 modified by the rapid evaporation of sweat. Even in negative 

 water loads the rate of evaporative loss is high; also it is said that 

 sweating is faster at high water contents of the body (Gregory and 

 Lee, '36). But suitable quantitative data are lacking for the con- 

 struction of an equilibration diagram. Concordantly, the paths of 

 water exchange are very differently partitioned, so that urinary 

 losses are relatively small except where diuresis has been aroused. 

 Evaporative rates sometimes exceed even the most profuse urinary 

 rates; individuals that have been observed under two conditions 

 that regularly result in maximal outputs are able to put out water 

 in sweat faster than in urine. 



The water deficit that usually prevails during daily life in the 

 desert (Adolph and Dill, '38) is too small to measure. But it can 



