176 PHYSIOLOGICAL CHEMISTRY. 



by BASSOW in 1842 on a dog. VERNEUIL performed the same on a 

 man in 1877 with successful results. These fistulas in animals 

 afford an excellent means of studying the secretion of gastric 

 juice and also the stomachic digestion. 



In a fasting condition the mucous coat is often nearly dry; 

 sometimes, especially on certain herbivora, it is covered with a layer 

 of viscid so-called mucus. If food is introduced into the stomach, 

 or if the mucous membrane is irritated in some way, then a secre- 

 tion of a thin, acid fluid, the real gastric juice, takes place. The 

 secretion may be produced by mechanical or thermal irritation (in- 

 troduction of cold water or pieces of ice into the stomach), or by 

 chemical irritants. Among the latter, alcohol and ether when in 

 too great concentration do not produce a physiological secretion, 

 but a transudation of a neutral or faintly alkaline fluid con- 

 taining albumin (CL. BERNARD). To this class of irritants 

 belong carbon dioxide and hydrochloric acid; the last especially 

 increases the secretion of pepsin (JAWORSKY), spices, meat 

 extracts, neutral salts, such as NaCl (which acts like alcohol in 

 too great concentration), and alkali carbonates. The alkali 

 carbonates are supposed by certain investigators to first neutralize, 

 and then produce a continuous secretion of, acid gastric juice. 

 The statements in regard to the action of different bodies 

 in the secretion of gastric juice are still rather uncertain and 

 often contradictory. 



Several investigators state that the secretion of gastric juice 

 may be stimulated by reflex means. After the introduction of 

 water into the stomach a proportionally poor and scanty secretion 

 takes place, while on the contrary the introduction of digestible 

 foods causes a more abundant and continuous secretion (SCHIFF, 

 HEIDENHAIN). But in these cases the secretion does not take 

 place immediately, but only after the absorption of the soluble 

 bodies has commenced. This fact justifies the usual custom of 

 commencing a meal with fluid nutritives such, as soup. 



The Qualitative and Quantitative Composition of the Gastric 

 Juice. The gastric juice, which can hardly be obtained pure and 

 free from residues of the food or from mucus and saliva, is a clear, 

 or only very faintly cloudy, and in man nearly colorless fluid of an 

 insipid, acid taste and strong acid reaction. It contains, as form- 



