I9I4] P. B. Hawk 429 



This period was generally from 5 to 10 days in length. At the 

 end of the period the diet, as fed during the preliminary period, was 

 again resumed for about one week, this interval constituting our 

 ßnal or after period. This experimental plan gave us an interval 

 of so-called excessive water ingestion preceded and foUowed by 

 periods during which so-called normal quantities of water were 

 daily ingested. 



So far as the influence of water upon the flow and activity of the 

 digestive secretions is concerned, we have demonstrated in the first 

 place, by experiments in vitro, that the digestive efficiency of the 

 salivary secretion as before mentioned is increased by dilution with 

 water, the optimum dilution being seven volumes. We have also 

 verified, in an indirect way, the Observation that water stimulates 

 the flow of gastric juice.^ Our index was the ammonia content of 

 the urine. We observed that an increased water consumption was 

 accompanied by an increase in the amount of ammonia in the urine 

 and that, for any given individual, a pronounced increase in the 

 water ingestion generally produced a correspondingly pronounced 

 increase in the ammonia Output, whereas a smaller increase in the 

 water ingestion was accompanied by a proportionate increase in the 

 Output of ammonia. Now, the ingestion of dilute mineral acid Solu- 

 tions by man or lower animals has also been shown to cause an in- 

 crease in the urinary ammonia. Furthermore, tests by several in- 

 vestigators upon dogs with a portion of the stomach isolated in the 

 form of a so-called Pavlov pouch or Pavlov stomach, have demon- 

 strated that the entrance of water into the stomach is accompanied 

 by an increased flow of gastric juice. Not only is the volume of 

 Juice increased, but the acidity of the juice as well. This being true, 

 the ingestion of water must of necessity cause the passage into the 

 intestine of an increased quantity of hydrochloric acid from the 

 gastric secretion. Therefore, in view of the fact that acid ingestion, 

 or the normal or pathological production of acid in the body, is 

 accompanied by an increased ammonia excretion, we Interpret the 

 heightened ammonia Output observed by us in our water studies as 

 due to the Stimulation of the gastric function. 



2 Since this paper was read the author in collaboration with Dr. M. E. 

 Rehfuss and Dr. Olaf Bergeim has demonstrated the stimulating power of water 

 in a direct way upon the human stomach. (Jour. Am. Med. Assn., 63, 909, 1914.) 



