114 



PHYSIOLOGICAL REGULATIONS 



Initial rates of water intake and of water output together (fig. 

 66) constitute an equilibration diagram. The intake never falls to 

 nothing ; even in the largest water excesses studied, its minimal rate 

 persists. Urine production falls to zero in moderate deficits of 

 water. Its rate is augmented less with excesses of water than 

 intake is augmented with deficits. Since gain and load are little 

 affected by the length of time elapsed as such, the diagram is not 

 greatly modified at longer times than 0.5 hour (fig. 67). 



The net exchanges of water (fig. 67) represent the combined 

 accomplishment of the total exchanges as modified at diverse loads. 

 Since body weights are actually being measured it is directly as- 

 sured that observed gains minus observed losses equal net gains. 

 In 2 hours any deficit is paid off, but only half of any excess is cov- 

 ered. 



>. OA 



Water Load 

 Fig. 69. Net velocity quotient in relation to mean water load. Each point is 

 derived from one group of 10 individuals in the first 1.0 hour of recovery. Load is % 

 of Bo; velocity quotient is obtained from figure 67 by dividing the net rate of water 

 exchange by the mean water load, = 1 Aour. 



For every rate of water output there is one rate of water intake 

 under the conditions prevailing (fig. 68). The roughly hyperbolic 

 form of the curve relating the two, emphasizes the reciprocal rela- 

 tion of the two processes, as though a high rate in one excluded 

 rapid activity in the other. 



Velocity quotients are larger in water deficits than in water 

 excesses (fig. 69). Recovery requires only one-third to one-half 

 the time after moderate desiccation that it requires after water 

 injection. It is most prompt at small loads. Among diverse ex- 

 cesses the net quotients are not much affected by magnitude of water 



