10 CHEMICAL PHYSIOLOGY. 



Se g fo S odTn?i f , e Tne comminuted food mixed with saliva arrives in 

 the stomach and excites this organ to a mechanical 

 and chemical action, termed digestion. The many- 

 little rennet glands situated in the walls of the stomach 



Gastric juice, secrete a liquid termed the gastric juice, which in man 

 contains 994*6 per mille of water and 5*39 of solid and 

 permanently fluid ingredients other than water. Of 

 these 3*0 are pepsine, 0*2 hydrochloric acid, with which 

 perhaps a small quantity of lactic acid is mixed, and 

 chlorides of the alkalies, with some phosphates of 

 earths. Singular is the presence of some calcium- 

 chloride in the juice. The juice has been examined 

 mainly as obtained from persons who by accident 

 had fistulous openings in their stomachs, and upon 

 dogs upon whom such fistulas had been formed by 

 operative interference. This led to the formation 

 of artificial juice, which requires the addition of 

 natural pepsine, and is therefore only in part 

 artificial. It serves, however, for the purpose of 

 studying stomach digestion upon many kinds of food, 

 and of supplying a kind of remedy in diseased con- 

 ditions in which the natural juice is supposed to be 

 deficient. 



ic7ui?e gas " This gastric juice possesses the power of dissolving 

 or reducing to a liquid state albuminous substances, 

 which are either by preparation, such as boiling, or by 

 nature, insoluble in water. Albumen, caseine, fibrine, 

 syntonine, the albuminous substances of vegetables, 

 gluten, and the collagene tissues or gristle, are under 

 the influence of gastric juice, or of a mixture of 

 pepsine and hydrochloric acid, dissolved to thickish 



