THE GASTRIC JUICE. 115 



to contain no fluid ; in man, however, a small amount of gastric 

 juice can usually be obtained by means of the stomach-tube, vary- 

 ing between 1 and 60 c.c. Larger amounts may be found under 

 pathologic conditions, and in the so-called Magensaftfluss of the 

 Germans it is not rare to find as much as 1000 c.c. in the early 

 morning, before any food has been taken. 



The amount of fluid which can be normally obtained from the 

 digesting organ is likewise variable. It depends upon the amount 

 of liquid ingested, the period of digestion, the character of the food, 

 the size and motor power of the stomach, etc. Exact figures, how- 

 ever, are lacking to represent these relations, and it is manifest that 

 such figures must always have reference to more or less diluted 

 gastric juice. 



Chemical Composition. A general idea of the chemical com- 

 position of the gastric juice may be formed from the following analy- 

 ses, which are taken from C. Schmidt; but it is to be noted that 

 the specimen of human gastric juice was contaminated with saliva 

 and somewhat diluted with water (the figures have reference to 1000 

 parts) : 



Acidity of the Gastric Juice. It has now been definitely 

 established that the acidity of normal gastric juice is referable to 

 the presence of free hydrochloric acid, and -to this only. This can 

 be shown by estimating the amount of chlorine and all basic sub- 

 stances that are present, when it will be found that after the acid 

 affinities of the latter have been saturated, a certain amount of 

 chlorine still remains, which can be referable only to hydrochloric 

 acid, and corresponds in its degree of acidity to that observed in 

 the gastric juice itself. 



During the process of digestion, however, other factors enter into 

 consideration'. In the beginning of digestion lactic acid is always 

 present when carbohydrates form part of the meal. Its amount, 

 however, is then quite small, and after the ingestion of Ewald's 

 test-breakfast, for example, does not exceed 0.3 pro mille. The 

 occurrence of larger quantities of lactic acid, as from 1 to 3 pro 

 mille, is always abnormal, and in many cases indicative of the 

 existence of carcinoma of the stomach. During the later stages 



