WATER AS A DIETARY COXSTITUEXT 291 



Influence on Intestinal Flora and Putrefaction. Since absorption is 

 more rapid and complete when water is taken with meals, there will be 

 less food material remaining in the intestine to furnish pabulum for 

 intestinal organisms. We would, therefore, expect to find a diminished 

 output of such organisms in the feces and a decreased intestinal putre- 

 faction. These facts have been emphasized by certain of our experi- 

 mental findings (Mattill and Hawk(c), Fowler and Hawk, Blatherwick 

 and Hawk (a) ). In one instance, the excretion of bacterial dry substance 

 in the feces was reduced from 8.0 grams to 6.2 grams per day as the result 

 of drinking about a liter of water per meal for a period of live days. 



That intestinal putrefaction is reduced when water is drunk freely 

 at meal time has also been shown using indican as the index (Sherwin 

 and Hawk, Hattrem and Hawk). The decreased intestinal putrefaction 

 brought about through the ingestion of moderate (500 c.c. ) or copious 

 (1,000 c.c.) quantities of water at meal time was probably due to 

 diminution in the activity of indol-forming bacteria following the acceler- 

 ated absorption of the products of protein digestion, and the passage of 

 excessive amounts of strongly acid chyme into the intestine. 



Influence on Absorption. The better utilization of the fat, carbohy- 

 drate and protein of the diet as just discussed furnishes proof that the 

 drinking of water facilitates the absorption of the products of the digestion 

 of our food. The drinking of water dilutes the material in the intestine 

 and aids in its absorption. Concentrated solutions are not readily absorbed, 

 as is shown by the experiments of London and Polovzova(a) and others. 

 The latter investigators showed that when concentrated solutions of glucose 

 are introduced into the intestine, a diluting secretion begins to flow from 

 the wall of the intestine. Its amount runs parallel with increasing con- 

 centration of the glucose solution, and at its maximum it may amount to 

 one-half the total quantity of blood in the animal. By this dilution and 

 also by absorption of sugar the concentration of the solution is brought 

 down to 6-8 per cent, a dilution at which absorption takes place very 

 readily in the lower intestinal tract. The secretion of the diluting fluid 

 begins with the coming in of the first glucose solution and continues fairly 

 uniformly, Since absorption is going on more or less continuously in 

 the intestine, the water taken with one meal aids hi diluting the products 

 of the previous meal which are in the intestine. Not only is enzyme 

 action more complete in dilute solutions but such solutions are also bet- 

 ter adapted to absorption. When the solutions to he absorbed are not 

 dilute, the organism must first make them so by pouring out a diluting 

 secretion ; if they have been made dilute, the organism is spared this task. 



Influence on Blood Volume and Blood Pressure. The practice of 

 drinking large volumes of water is sometimes criticized on the theory that 

 it increases blood volume and consequently causes a rise in blood pres- 

 sure. However, some Yale experiments (Bogert, Underbill and Mendel) 



