Contributions to the physiology of digestion and to dietetics / by W. G. Aitchison Robertson.

  • Robertson W. G. Aitchison (William George Aitchison)
Date:
1903
Catalogue details

Licence: In copyright

Credit: Contributions to the physiology of digestion and to dietetics / by W. G. Aitchison Robertson. 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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    a feeble degree of acidity, the conversion of starch is carried on to a great extent in the stomach, as is shown in the case of pernicious anaemia, where probably amylolysis was carried to its full limit, and the products either at once absorbed or passed on. In these experiments the starch was introduced directly into the stomach by means of the stomach tube. In this way there was no admixture of saliva except what was swallowed sub- sequently. The Table shows that in cases where the normal acidity was not lessened, this swallowed saliva had little conversive action on the starch. It likewise shows that even a pure starch solution introduced into the stomach promotes the secretion of hydrochloric acid,—a fact which, on (i priori grounds, we should not have expected as being inimical to the digestion of amylaceous substances. From the high degree of conversion which the starch has undergone in the stomach of the patient with pernicious anaemia, I should be inclined to think that this was either due to swallowed saliva or to a conversive ferment secreted by the gastric mucous membrane, as has been described in the stomach of the pig. The above, however, is not the normal condition in which starchy food is received into the stomach, for it is always mixed up with and accompanied by the products of salivary secretion. In order to see what changes occur in starch solutions received into the stomach under such conditions, I experimented as follows:— Combined Effect of Salivary and Gastric Digestion on Starch. Having thoroughly washed out the stomach, I allowed the following patients to eat slowly a fluid mucilage of boiled starch. I. Healthy Digestion.— 250 c. c. boiled starch solution eaten slowly. Fifteen minutes later I drew off 40 c. c. The total acidity was equal to 0 061 per cent. Starch and erythrodextrin were present in large amount, and reducing sugar amounted to 016 per cent. I carefully neutralized this fluid, and kept it at a temperature of 38° C. to see if any further conversion would take place. After being kept thus for forty-five minutes, no further change had occurred. The ptyalin ferment had therefore in this case been killed by this degree of acidity of the gastric contents, viz., 0-061 per cent, hydrochloric acid. One hour after the ingestion of the starch solution other 45 c. c. were syphoned off. The total acidity equalled 0102 per cent. ; much unchanged starch was present, with traces of erythrodextrin and sugar. This also was neutralized and kept at 38° C. for forty-five