46 GASTRIC JUICE. 



different substances, constitutes the true digestive principle; its 

 solution, on being boiled, certainly loses the property of effecting 

 the characteristic change on the protein-bodies and gelatigenous 

 substances, but does not coagulate like albumen, as was formerly 

 supposed from experiments performed with artificial gastric juice. 



The ratio in which the mineral constituents of the gastric juice 

 stand to the organic, is a somewhat varying one ; in the gastric 

 juice of the horse, Gmelin found 1'05# of organic, and 0*55^ of 

 inorganic constituents, while on the other hand Frerichs found 

 0'98 of organic and 0*74^ of inorganic matters; in the gastric 

 juice of the dog Frerichs found 0'72 of organic and 0'43^ of 

 inorganic constituents, while I found from 0'86 to 0*99^ of the 

 former and from 0'38 to 0'56f of the latter. 



By the term artificial gastric juice we understand a fluid which 

 is obtained by treating the glandular tissue of the stomach in a 

 peculiar manner with dilute hydrochloric acid, and which possesses 

 the characteristic property, in common with the natural gastric 

 juice, of converting nitrogenous articles of food into soluble, non- 

 coagulable substances. 



After Eberle* had shown that the gastric juice, when removed 

 from the animal body, retains the property of inducing peculiar 

 changes in the food, and that by digesting the mucous membrane 

 of the stomach with extremely dilute acids, we obtain a fluid which 

 possesses true digestive powers, it was proved by Schwann f that 

 it is only the glandular structure of the stomach which possesses 

 the property of yielding a digestive mixture with acids, and further, 

 that corrosive sublimate throws down a precipitate from it, which 

 possesses the digestive power in a high degree. To this substance 

 Schwann gave the name of pepsin. Wasmann J who investigated 

 the subject even more fully than Schwann, demonstrated that the 

 source of the gastric juice and of this pepsin lay in the gastric 

 glands, which he carefully observed and described; he likewise 

 attempted to exhibit pepsin in a purer state. 



He proceeded in the following manner : the glandular layer in 

 the stomach of the pig, which extends chiefly from the greater 

 curvature towards the cardia, was carefully detached and washed, 

 without being cut up ; then digested with distilled water at a 

 temperature of from 30 to 35. After some hours the fluid 

 was poured away, the membrane was again washed in cold 



* Physiologie der Verdauung. "Wiirzburg, 1834. 



t Fogg. Ann. Bd. 38, S. 358. 



I De digestione nonnulla, diss. inaug. Berol. 1839. 



