Some practical results from the chemical examination of the contents of the healthy stomach / by A. Lockhart Gillespie.
- Date:
- 1893
Licence: Public Domain Mark
Credit: Some practical results from the chemical examination of the contents of the healthy stomach / 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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![also a source of some uncertainty as to the end of the reaction in testing the acidity with phenol-phthalein. In both cases consider- able dilution with distilled water is advisable, and, in estimating the acidity, a larger quantity of phenol-phthalein than usual. For this reason, again, no colour which changes its shade on transition from acid to alkali can be used with any accuracy at all. One which is colourless with the one and coloured with the other is requisite. Experiment V.—Another similar experiment performed with a glucose solution resulted in the acidity after a few hours being equal inside and outside. The deductions from these experiments are as follows:—1. That proteids in solution have the power of attracting, and probably combining with, hydrochloric acid. 2. That this acid so combined, even if greater in quantity and strength, does not prevent more free hydrochloric acid from dialysing through. 3. This combined acid, if placed in a dialyser with water round it, does not dialyse through so quickly as the uncombined acid. 4. That hydrochloric acid has no power of combining with carbohydrates, at least with starch or glucose. 5. That as digestion proceeds, and the lower proteids pass through the membrane, the combined acid passes through with them, and the total acidity inside falls. 6. If in one case the acidity outside be less, and in another greater, the contents being much the same, the acidity inside does not vary in proportion. 7. That, if the proteid varies in concentration, the acidity varies with it. 8. That the presence of pepsine increases the avidity with which hydrochloric acid combines with proteid bodies. The experiments on milk prove conclusively that the increase of acidity varies directly with the density of the contents ; but considering the experiment on potato, it is seen that in these experiments it is not the density of the whole bulk of the contents which is the factor at work, but the proportion of proteids in them. In the series of digestions of milk, for instance, where the proportion of proteid is comparatively high, the acid curve is high. In the potato experi- ment the proportion of proteids is extremely small (Konig states that potato contains 2 per cent, of proteids), the combined acidity is low; while in the experiment on substances almost purely proteid in character, the acidity was still rising when the experiment had to be stopped. 9. It is possible to ascertain roughly the proportion of acid which combines with proteids. In the milk series it varies from 8T per cent, to 17*5 per cent., and considering, as above, that potato contains 2 per cent, of proteids, the amount of acid combined is between 7 and 8 per cent, at the third hour, but is probably higher, as the quantity of proteid which had dialysed was not noted ; while in the third experiment, if the ])roportions are worked out, excluding (he hgures at one hour, which give a figure of 32 per cent., the](https://iiif.wellcomecollection.org/image/b21976351_0012.jp2/full/800%2C/0/default.jpg)
