THE GASTRIC JUICE AND STOMACH DIGESTION. 165 



measurement ; and thirdly, if we measure the quantity obtainable by 

 either of these means during a short period, it does not follow that it 

 would continue to be secreted at the same rate during the remainder of 

 the twenty-four hours, because the rapidity of its production is so much 

 influenced by the condition of the digestive process. Neither can we 

 draw from an animal with a stomach fistula all the gastric juice which 

 will flow during twenty-four hours, and consider that as representing 

 the normal daily quantity ; because we should then be drawing away a 

 quantity of secreted fluid which in the natural condition is retained in 

 the alimentary canal and reabsorbed by the bloodvessels. Its supply 

 would therefore be necessarily diminished by the continuous loss of 

 fluids from the system. Notwithstanding these difficulties, however, a 

 sufficient number of facts have been observed to show that the usual 

 daily secretion of the gastric juice is undoubtedly far more abundant 

 than that of the other digestive fluids. Dr. Beaumont was able to ob- 

 tain from the stomach of St. Martin, simply by the introduction of a 

 gum-elastic catheter, 44 grammes of gastric juice in the course of fifteen 

 minutes. We have often collected from a medium-sized dog, under the 

 stimulus of commencing digestion, from 60 to 75 grammes in the same 

 time. Bidder and Schmidt found that, in a dog weighing about 15.5 

 kilogrammes, they were able to obtain, by separate experiments, con- 

 suming in all twelve hours, 793 grammes of gastric juice. If these 

 separate experiments, therefore, as is probable, indicate the average 

 rate of its production at diflerents parts of the day, the entire quantity 

 for twenty-four hours, in an animal of that size, would be 1586 grammes ; 

 or about 100 grammes for every kilogramme in weight of the body 

 of the animal. By applying this calculation to a man of ordinary size 

 the authors estimate the average daily quantity of gastric juice in 

 the human subject as about 6500 grammes. It is, however, quite 

 unsafe to estimate the quantity of this secretion as necessarily in pro- 

 portion to the weight of the body. It is probably more strictly in 

 proportion to the quantity of food which it is its function to digest ; and 

 the dog habitually consumes a much larger quantity of animal food, in 

 proportion to his size, than a man. Schmidt, in the series of observa- 

 tions already quoted, 1 performed upon a woman with accidental gastric 

 fistula, whose weight was only 53 kilogrammes, obtained, as the mean 

 result of several observations, 580 grammes of gastric juice from the 

 fistula in the course of an hour. In this case, however, the secretion 

 was much poorer in its characteristic ingredients than that usually 

 obtained from the dog, and was also much inferior in digestive power. 



Another method which has been adopted for estimating the quantity 

 of the gastric juice is to ascertain the amount capable of digesting the 

 quantity of albuminous food required per day. According to the experi- 

 ments of Lehmann, 2 one gramme of coagulated albumen, calculated as 



1 Annalen der Chemie und Pharmacie, 1854, Band xcii. p. 42. 



2 Physiological Chemistry. London, 1853, vol. ii. p. 53. 



