22 



PHYSIOLOGICAL EEGULATIONS 



the variation among tests upon one individual. Also, recognizable 

 differences exist among individuals, as though the capacities for 

 metabolizing water were of diverse orders; these too are disre- 

 garded. Further, there is significant acclimatization in an indi- 

 vidual that has been repeatedly given water in large doses, whereby 

 the speed of disposal is increased. Such matters may await later 

 treatment. 



The course of water exchanges is partially different if, instead 

 of the dog as weighed, one considers water content of the dog minus 

 the alimentarv tract. Then the water in stomach and intestine is 



+2 - 



% 



Hours 



Fig. 5. Course of water load ( % of Bo) after water is given by stomach tube. Loads 

 represent the means in 9 individuals upon each of which several tests of urinary water 

 output were completed. Absorbed volumes are the means in those 9 individuals when 

 killed at various intervals within 0.6 hour after water administration, in order to find how 

 much water remained in the alimentary tract. Data of Klisiecki et al. ('33a). Eedrawn 

 by permission of the Eoyal Society of London. 



counted as being outside the body, and the rate of absorption modi- 

 fies the increment or load of water present at any instant. Absorp- 

 tion has been directly measured at only one load administered; 

 with considerable variation among individuals, the amount ab- 

 sorbed was found to be proportional to time elapsed up to complete 

 absorption in 0.6 hour. The load characterizing the dog minus 

 alimentary tract is indicated in figure 5. This diagram serves 

 partially to locate the water at each instant during the test. Actu- 

 ally most of the water given is still unexcreted when absorption is 

 apparently complete. 



