792 PHYSIOLOGY OF DIGESTION AND SECRETION. 



intestine, being forced out in a series of spurts by the contractions of 

 the stomach. Within a comparatively short time practically all 

 the water can be recovered in this way, none or very little having 

 been absorbed in the stomach. For example, in a large dog with a 

 fistula in the duodenum, 500 c.c. of water were given through the 

 mouth. Within twenty-five minutes 495 c.c. had been forced out of 

 the stomach through the duodenal fistula. This result is not 

 true for all liquids ; alcohol, for example, is absorbed readily. 



Salts. The absorption of salts from the stomach has not been 

 investigated thoroughly. According to Brandl, sodium iodid is 

 absorbed very slowly or not at all in dilute solutions. Not until its 

 solutions reach a concentration of 3 per cent, or more does its absorp- 

 tion become important. This result, if applicable to all the soluble 

 inorganic salts, would indicate that under ordinary conditions they 

 are practically not absorbed in the stomach, since it can not be sup- 

 posed that they are normally swallowed in solutions so concentrated 

 as 3 per cent. In the same direction Meltzer reports that solutions 

 of strychnin are absorbed with difficulty from the stomach as com- 

 pared with the intestines, rectum, or even the pharynx. It is said 

 that the absorption of sodium iodid is very much facilitated by 

 the use of condiments, such as mustard and pepper, or alcohol, 

 which act either by causing a greater congestion of the mucous 

 membrane or perhaps by directly stimulating the epithelial cells. 



Sugars and Peptones. In regard to the sugars the experiments 

 of von Mering and Brandl indicate that while absorption takes 

 place it is not rapid nor marked unless the solutions are quite 

 concentrated (5 per cent.) , and we may infer, therefore, that in an 

 ordinary meal the sugar formed from the starchy foods by the 

 action of the ptyalin is passed on to the intestine for further diges- 

 tion and absorption. Whether or not any of the digested proteins 

 are absorbed from the stomach has been and still is a matter of 

 controversy. Some of the older experimenters stated that as 

 much as 20 to 30 per cent, of the protein of a meal might be 

 absorbed in the stomach, but the results of the more recent work, 

 on the contrary, indicate that little or no absorption takes place 

 under normal conditions.* When a definite amount of protein was 

 introduced into the stomach of an experimental animal it could 

 all be recovered, as estimated by nitrogen determinations, from a 

 duodenal fistula. 



Fats. As we have seen, fats probably undergo no digestive 

 changes in the stomach. The processes of saponification and emul- 

 sification are supposed to be preliminary steps to absorption, and 

 these processes take place usually after the fats have reached the 

 small intestine. 



* London, loc. tit. 



