COERELATIVES OF WATER CONTENT IN OTHER SPECIES 243 



tion of acetylene as administered hy Grollman's procedure, are 

 increased during water excess, the conclusions in this form will 

 stand. But if it be inferred that nitrogen is liberated from protein 

 faster, or that the blood passes through the heart faster, then when 

 other methods and other corrections and other factors receive 

 recognition, the conclusions will need restatement. 



Among alimentary secretions, particular attention has been 

 given to measurements of salivary flow ( Cannon, '18 ; Gantt, '29 ; 

 Winsor, '30; Gregersen and Bullock, '31). In most of them the 

 deficits of water in the body are not recorded, and for present pur- 

 poses are merely approximated from statements of the times 

 elapsed in producing the state of desiccation. By each of the arbi- 

 trary procedures chosen, the rate of flow decreases with increasing 

 deficits of water content. It may not be that, by extrapolation, the 

 rate increases with water excesses ; that needs investigation, but 

 happened not to interest those who wanted to relate the water sup- 

 ply of the mouth to the sensation called ' ' thirst. ' ' 



A few estimates of Baird et al. ( '24) and of others indicate 

 rapid secretion of gastric juice following water ingestion (+ AW). 



Rates of renal excretion of numerous substances are modified 

 with water excesses ; a few are unaffected between urinary outputs 

 of 0.04 and 0.4% of Bo/hour (e.g., creatinine (Marshall, '20; 

 Kriiger, '37) ). The two most abundant substances in human urine 

 are chloride (Kingsley) and urea (Marshall, '20) ; the time elapsed 

 since water load is established is an important factor in the elimi- 

 nation of both of them. The relations between solutes and water 

 in excretion serve to characterize the excretory processes in man; 

 no differences from dog have been recognized. 



Clearances through the kidneys are well known to be correlated 

 with rates of water excretion (urea, Austin et al., '21) and hence 

 with water content. Ordinarily clearances are measured after 

 excessive administration of the substance whose clearance is being 

 studied. Within limits, the copious excretion of the substance 

 itself modifies the rate of water excretion {i.e., solute diuresis). 

 Again, each substance cleared has its own quantitative relation to 

 water load (Smith, '37). Man could be distinguished from dog 

 solely by the several influences of water content (augmentations) 

 upon clearances. 



Behaviors of diverse sorts have been qualitatively reported in 

 extreme water loads. Large excesses are accompanied by muscu- 



