188 PHYSIOLOGICAL CHEMISTRY. 



continues, and therefore the presence of dextrin and sugar can bt 

 detected in the contents of the stomach. Besides this the car- 

 bohydrates in the stomach may in part undergo a lactic-acid fer- 

 mentation, probably caused by the micro-organisms present. 



According to the investigations of ELLENBERGER and HOFF- 

 MEISTER on horses and pigs, after a meal rich in amylaceous bodies 

 in the first phase of the digestion, an AMYLOLTSE takes place with 

 the formation of lactic acid; then gastric juice containing hydro- 

 chloric acid is secreted, then follows a second phase in which the 

 proteolyse takes place. As a rule, the formation of lactic acid de- 

 creases as the secretion of hydrochloric acid increases. EWALD 

 and BOAS claim that a similar condition also exists in human 

 beings. They claim that there is in the first stage of digestion a 

 predominance of lactic acid in the stomach, in the second a simul- 

 taneous occurrence of lactic and hydrochloric acids, and in the third 

 stage almost exclusively hydrochloric acids. KJAERGAARD has 

 lately formed the same conclusions from his investigations on 

 children and robust persons. In persons with altered blood-vessels 

 due to senility the contents of the stomach show chiefly the presence 

 of lactic acid. Such persons digest large amounts of carbohydrates, 

 while the digestion of albuminous bodies is decreased. 



The FATS which are not fluid at the ordinary temperature melt 

 in the stomach at the temperature of the body and become fluid. 

 In the same way the fat of the fatty structure is set free in the 

 stomach by the gastric juice which digests the cell-membrane. The 

 gastric juice itself seems to have no action on fats, but, according to 

 recent statements, a splitting of the neutral fats into fatty acids and 

 glycerin takes place, though not to a great extent. This splitting is 

 not dependent on the bacteria of the contents of the stomach, or 

 at least only to a small extent (KLEMPERER and SCHEURLEN"). The 

 soluble salts of the food naturally are found dissolved in the 

 liquids of the contents of the stomach ; but the insoluble salts may 

 also be dissolved by the acid of the gastric juice. 



Since the hydrochloric acid of the gastric juice prevents the 

 contents of the stomach from fermenting with the generation of 

 gas, those gases which occur in the stomach probably depend, at 

 least in great measure, upon the swallowed air and saliva, and 

 upon those gases generated in the intestines and returned through 



