ELIMINATIOX OF WATER FROM THE HUMAN BODY 



537 



Table 1. — Density of Water Prepaeed from Urine 



AFTER THE INTAKE OF DILUTED HEAVY WaTER 



processes carried out. One of us took then in one experiment 150 cc. 

 and in another 250 cc. water containing 0.46 per cent heavy water 

 showing a density difference against normal water of 480 X 10~^. As 

 the increase in density of the urine obtained after the intake of these 

 quantities was only a few units in a million, an experiment was made 

 in which 2000 cc. were taken. The increase in the density of the water 

 obtained was then up to 25 : 10^. Some of the results are seen from 

 Table 1. 



From the above figures, it follows that after half an hour from the 

 beginning of the intake of water, some of the water drunk is found in 

 the urine, though only 0.2 per cent of the amount taken. The bulk of 

 the water leaves the body at a slow rate and it takes 9 i 1 days before 

 half of the water taken has left the body. 



We controlled the water balance during the experiments and found 

 (in hot summer weather) that on an average 60 per cent of the water 

 lost, left the body through transpiration and evaporation. In the posses- 

 sion of these data, and as we find that the density of urine water and 

 transpiration water is the same within the limits of our accuracy relevant 

 for these considerations ( J:: 5 per cent of the density excess), we can 

 calculate the time which elapses before half of the water taken left the 



