GASTRIC GLANDS 93 



salivary digestion proceeds in some small degree in the stomach. 

 Saliva is swallowed with the food, and until the reaction becomes 

 acid (which cannot be immediately), there is no reason why the 

 conversion of starch into maltose should not proceed. It is also 

 true that the mere acid of the gastric juice can slowly convert 

 cane sugar into dextrose. Simple acidulated water will do the 

 same. 



(C) On Fats. Neither is there any fat-splitting enzyme in the 

 gastric secretion. So far as any chemical change is concerned 

 the fats leave the pylorus in exactly the same condition as they 

 entered the mouth. Their physical condition, however, under- 

 goes some change in the stomach. The body temperature is 

 sufficient to liquefy them, the vesicles in which the droplets are 

 contained are dissolved, and thus set free, they become a part 

 of the mechanical mixture, chyme, and are made easier subjects 

 of intestinal digestion. 



(D) On Albuminoids. The albuminoids are acted upon by 

 pepsin and hydrochloric acid in much the same way as are the 

 proteids. Taking gelatin as a type, gelatoses are formed instead 

 of proteoses. It is stated that peptic digestion does not go fur- 

 ther than the gelatose stage with the albuminoids, conversion 

 into peptones taking place under the influence of trypsin. 



Resistance of Stomach Wall to Digestion. It would be in- 

 teresting to know why the stomach (or the intestine) does not 

 digest itself. If a portion of the stomach of another animal be 

 placed in that of a living animal, it will be digested; or if the 

 circulation be cut off from a limited area of the stomach, the 

 secretion will frequently digest that part of the organ and bring 

 about a perforation; or further, if any living part of an animal, 

 as the leg of a frog, be fastened in the stomach of another animal, 

 it will likewise be digested. The last instance would seem to 

 lead to the conclusion that living matter can be digested, but 

 in reality it is shown (Bernard) that the tissue is first killed by 

 the acid, and that no digestion takes place in the alkaline intes- 



