GASTRIC GLANDS 93 



(B) On Carbohydrates. There is no enzyme furnished 

 by the stomach to affect any of the carbohydrates. It is 

 true that 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 con- 

 dition as they entered the mouth. Their physical condition, 

 however, undergoes 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 further 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 

 interesting 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 di- 

 gested ; 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 (Ber- 



