WATER EXCHANGES OF DOG 



47 



tinues during recovery after administration ceases, but each rate 

 of loss is somewhat less than when sudden excesses are given the 

 dog to obtain an equal load. 



§ 13. Stationary states of deficit 



Negative increments of water are readily maintained in dogs 

 with fistula of the esophagus. Water taken into the mouth escapes 

 into a measuring vessel, thus indicating the amount drunk by the 

 dogs, but does not enter the remainder of the body to modify its 

 water content. On constant diet these dogs may receive inadequate 

 amounts of water by stomach, creating water (weight) deficits of 



Tig. 



Woter Load 

 28. Eate of sham-drinking of water (% of Bo/hr.) in relation to negative water 



load ( % of Bo) in two dogs with esophageal fistulas. Each measurement is the mean for 

 a period of 24 hours. Twelve such measurements are averaged, in order of water or 

 weight deficit, for each of the points plotted, giving the regression of rate on load. 

 Eedrawn from Adolph ('39a). 



diverse magnitudes. Hour after hour the sham-drinking inter- 

 mittently continues, at mean rates (fig. 28) proportional to the 

 deficit prevailing. 



The intermittent drinking of the dog with esophageal fistula 

 approaches in velocity only momentarily the sudden drinking of 

 the dog that ingests (Adolph, '39a). But spread over an arbitrary 

 interval of one hour or more the steady rate is found to surpass the 

 initial rate. The intermittent character of drinking ordinarily 

 allows time for absorption to follow ingestion. Evidently the ali- 

 mentary tract meters the water taken, before any postabsorptive 

 influence upon bodily composition occurs. The subsequent failure 

 of the postabsorptive factors to confirm the earlier alimentary fac- 



