160 FUNCTIONS OF NUTRITION. 



is also sustained by the experiments of Henniger,* who subjected pep- 

 tone to a process of dehydration by means of anhydrous acetic acid at 

 80 C., obtaining as the result an albumen-like substance coagulable by 

 heat. 



Digestion of the Stomach Tissues by Gastric Juice. As the gastric 

 juice, or acidulated pepsine solutions, can dissolve the substance of all 

 albuminous tissues, they have the same effect on the walls of the 

 stomach itself. If the gastric mucous membrane be macerated in acid- 

 ulated water at the temperature of 38 C., the mixture no sooner absorbs 

 pepsine from the gastric follicles than it becomes digestive, and con- 

 sequently dissolves the tissue of the membrane itself. It, therefore, 

 requires some explanation to understand how the stomach can produce 

 a secretion which is capable of destroying its own substance. This is, 

 no doubt, due to the manner in which the secretion takes place. We 

 have already seen that pepsine is a constant ingredient of the glandular 

 cells formed in the intervals of digestion, while the free acid is produced 

 by a sudden exudation, on the introduction of food. The acid is also 

 poured out only near the orifices of the glandular follicles, being at 

 once discharged into the cavity of the organ and absorbed by the 

 alimentary mass. The gastric juice can exert its digestive power only 

 in the presence of an acid reaction, and the mucous membrane is conse- 

 quently protected from its influence by the alkalescence of its intersti- 

 tial fluid, maintained by the circulation of the blood. The nature of 

 the change by which a free acid is produced from the constituents of 

 the alkaline blood is not certainly known, but there is no doubt that 

 this acid first appears after the exudation of the fluids, and it is also 

 plain that its liberation must increase for the moment the alkalinity of 

 the remaining constituents of the mucous membrane. 



But after death self-digestion of the stomach is not an unfrequent 

 occurrence. It does not take place in the majority of cases, because, as 

 a rule, digestion has been suspended during the last hours of life, and 

 the stomach contains little or no gastric juice. On the other, hand, 

 when death takes place suddenly, soon after the ingestion of food, and 

 when the body is not too rapidly cooled, the accumulated gastric juice 

 acts on the walls of the stomach as well as on the food which it con- 

 tains. Owing to the stoppage of the circulation, the local alkalescence 

 of the fluid is no longer maintained, and the free acid at last prepon- 

 derates over the blood remaining in the capillary vessels. The mucous 

 membrane, thus imbibed with an active digestive fluid, in the course of 

 ten or twelve hours may be so softened and disintegrated as to expose 

 the submucous connective tissue ; and occasionally all the coats of the 

 organ have been found destroyed, with a perforation into the peritoneal 

 cavity. After death, accordingly, the tissues of the stomach are affected 

 by the gastric juice in the same way as the albuminous ingredients of 

 the food. 



* Revue des Sciences Medicales. Paris, 1878, tome xii., p. 721. 



