458 DIGESTION. 



authors the stomach has a sort of " selective capacity," but this is strongly 

 disputed by SCHEUNERT and GRIMMER. 1 Nevertheless the researches 

 of CANNON 2 on cats, making use of another method, have shown that 

 this is true. After preliminary hunger the animals received different 

 food, such as meat, fat, and carbohydrate mixed with bismuth subnitrate 

 and then with the aid of the RONTGEN rays the time was noted when the 

 food passed into the intestine. The carbohydrate leaves the stomach 

 first, the proteins next, and the fats last. If the carbohydrate is given 

 before the protein food, then it leaves the stomach with ordinary rapidity ; 

 while if protein food and then carbohydrate is given the passage of the 

 carbohydrate is retarded. A mixture of protein food and carbohydrates 

 leaves the stomach more slowly than carbohydrates alone, but faster than 

 protein food alone. The fat, which remains in the stomach for a long time 

 and leaves the stomach only in amounts which are absorbed or removed 

 from the duodenum, retards the passage of the protein foods as well 

 as the carbohydrates. 



The reason why different food-stuffs leave the stomach with unequal rapidity 

 is explained by CANNON by the above-mentioned action of the hydrochloric acid 

 upon the pyloric sphincter. The proteins combine with the hydrochloric acid 

 and hence its action upon the sphincter becomes weaker, while this is not the 

 case with the carbohydrates. If the carbohydrates are moistened with alkali 

 they leave the stomach more slowly than usual and the acid proteins, on the con- 

 trary, leave the stomach earlier than other proteins. 



As our knowledge of the digestibility of "the different foods in the 

 stomach is slight and uncertain, so also our knowledge of the action of 

 other bodies, such as alcoholic drinks, bitter principles, spices, etc., on the 

 natural digestion is very uncertain and imperfect. The difficulties which 

 stand in the way of this kind of investigation are very great, and there- 

 fore the results obtained thus far are often ambiguous or conflict with 

 each other. For example, certain investigators have observed that small 

 quantities of alcohol or alcoholic drinks do not prevent but rather facili- 

 tate digestion ; others observed only a disturbing action, while still others 

 report having found that the alcohol first acts somewhat as a disturbing 

 agent, but afterward, when it is absorbed, produces an abundant secretion 

 of gastric juice, and thereby facilitates digestion. The accelerating 

 action of alcohol upon the flow of gastric juice has already been men- 

 tioned on page 439. 



In regard to the importance of the stomach we used to be of the gen- 

 eral opinion that an abundant peptonization of protein does not occur in 

 the stomach, and that the food rich in protein is more likely to be chiefly 

 prepared in the stomach for the real digestion in the intestine. That the 



1 Scheunert, Zeitschr. f. physiol. Chem,, 51; Grimmer, Bioch. Zeitschr., 3. 

 3 Amer, Journ. of Physiol., 12 and 20. 



