50 GASTRIC JUICE. 



hydrochloric acid enters into its well-known soluble combinations 

 with albumen, &c. By the repeated addition of hydrochloric 

 acid, a digestive fluid or this pepsin-hydrochloric acid might 

 preserve its digesting power for ever, unless the fluid became 

 saturated with the dissolved substances, or the conjugated acid 

 underwent decomposition. 



Ingenious as this view of Schmidt's undoubtedly is, and singu- 

 larly as it seems to harmonize with certain facts, there are other 

 arid very important facts which appear to render its correctness 

 doubtful. The existence of this pepsin-hydrochloric acid has not 

 been recognized by any analysis of a combination of it with a 

 mineral base or with an albuminous substance. Although I have 

 instituted numerous experiments regarding the quantitative rela- 

 tions between the digestive fluid and the substances to be digested, 

 I cannot ascertain that there are any such proportions between 

 the acid and the digested substance as at all accord with the 

 ordinary acid or basic combinations of acid and base; and further, 

 the digested substances (the peptones) separated by the acid, are 

 altogether different from the original albumen, fibrin, casein, &c., 

 which, however, according to Schmidt, combine in a simple 

 manner with this complex acid, and then directly undergo solu- 

 tion. Further grounds for opposing this hypothesis will become 

 apparent when we enter more fully into the consideration of the 

 peptones. 



Very little is known regarding the abnormal constituents which, 

 under certain physiological or pathological conditions, may occur 

 in the gastric juice. We know that in the normal condition, the 

 stomach, when it is empty, is invested with a layer of mucus, 

 which exhibits no reaction with vegetable colours. In gastric 

 catarrh, this mucus accumulates in larger quantities, and on 

 chemical examination is found to present little difference from 

 the secretions of other mucous membranes ; and, like them, it 

 only in a slight degree possesses digestive powers on the addition 

 of a free acid : even while in the stomach it appears in part to 

 undergo decomposition, and subsequently, on being mixed with 

 amylaceous or saccharine food, to enter into abnormal processes 

 of fermentation, as, for instance, acetic, butyric, and lactic fermenta- 

 tion. The contents of the stomach then contain far more free acid 

 than occurs in them in normal digestion. The two last-named 

 processes of fermentation are especially promoted by the presence 

 of fat, which gives rise to heartburn, a sensation of constriction in 

 the throat, and vomiting; and at the same time, there is often a 



