On the gastric digestion of proteids / by A. Lockhart Gillespie.

Date:
[1892?]
Catalogue details

Licence: Public Domain Mark

Credit: On the gastric digestion of proteids / by A. Lockhart Gillespie. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    It is clear, then, that although the addition of *018 percent, of free HCl was sufficient to stop the amylolytic action of the salivary ferment, *0318 per cent, of the combined acid only checked it, while '01575 per cent, had little effect. As the hydrochloric acid in the stomach at the commence- ment of digestion of a proteid meal is entirely combined, it is obvious that the continuation of the amylolytic action of the salivary ferment is possible for a short time. Forms of Proteid-hydrochloride. All the reactions mentioned above may occur in the absence of pepsine, when acid aud proteid are simply brought together. The amount of acid taken up by the albumen under these circumstances is nearly constant,—some variation, however, being observed in direct proportion to the strength of acid solution used. Without pepsine, hydrochloric acid combines with albumen only up to the proportion required to form acid albumen: the proportion may be less than that required, but never more, unless we look on the charring effect of strong acid as primarily a combination. This acid, nevertheless, though now combined, is still able to act further on the proteid if pepsine be added to the solution. For, if pepsine be added to a mixture of HCl and albumen, part of which is acid albumen and part serum albumen, but in which there is no free HCl present, further and simpler proteid bodies are formed, but only to a limited extent, and then at the expense of some of the acid albumen, which perhaps may become serum albumen again. Hydrochloric acid combining with proteids in the absence of pepsine can saturate the molecules, but cannot split them further. Experiment VII. illustrates this fact, and will also serve as a text for further observations on the action of HCl on proteids in the presence of pepsine. A solution of egg albumen, of which 9 ccs. contained 1 grm., was used, to which solution hydrochloric acid in varying strengths was added. All the figures in the tables have been corrected for ash. The quantities were as follows :— 1. 2 grms. albumen '38528 grm. HCl 86 ccs. in all, '448 per cent, acidity. 2. 1-98 9 y •24948 n 66 •378 3. 1-96 9 } •08424 )) 36 )9 •234 4. 1-96 )) •08424 9 ) 36 99 •234