The digestion of sugars in health / by W.G. Aitchison Robertson.

  • Robertson, W. G. Aitchison (William George Aitchison)
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: The digestion of sugars in health / by W.G. Aitchison Robertson. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    into grape sugar before absorption from the alimentary canal. Bouchardat and Sandras state that, under tlie influence of the gastric juice and of the lining membranes, cane sugar is changed into invert sugar and lactic acid, and absorbed as such, and that it must undergo inversion before it can be absorbed and used up in the blood. The gastric juice contains,besides pepsin,a milk-curdling ferment; and, according to Hammersten, there is also a lactic acid ferment that acts on milk sugar. But in opposition to this last statement, it is a fact that a pure solution of lactose does not undergo fer- mentation vphen acted on by the gastric juice. The acidity of the gastric secretion is now universally believed to be due to free hydrochloric acid (as was first conclusively proved by Bidder and Schmidt), which amounts usually to 0'17 to 0-3 per cent. During the first stage of digestion, even though the contents of the stomach are acid, no free hydrochloric acid is found. The period when it appears varies in different individuals, and also varies with the diet. After breakfast it may not be found until 45-60 minutes have elapsed, while after a full dinner it is not evident until after the lapse of two hours. Lactic acid is said by some to exist normally in gastric juice, though it never reaches an amount exceeding 1 per mille. Free hydrochloric or lactic acid can seldom be detected in the stomach of infants. Of the total acidity which one estimates in the gastric juice during digestion, only a very small amount may be due to free hydrochloric acid, the greater part being caused by the presence of acetic, butyric, and lactic acids. Action of Gastric Secretion on Cane Sugar. Dalton,Leube, and others state that outside the body the gastric juice slowly changes cane sugar into glucose. Laborde, however, affirms that the inversive power of the gastric juice is less than that of a solution of hydrochloric acid of the same strength ; but if a trace of hydrochloric acid be added to the gastric juice, its inversive power becomes greater than that of the dilute solution of hydrochloric acid alone. Leube makes an exactly opposite statement. Brown-Sdquard, Schiff, and Smith say that cane sugar is inverted in the stomach, and Bourquelot thinks that it is partly inverted in the stomach, but that part passes directly into the blood and is there inverted by the carbonic acid. Hay could find no inversive ferment in the gastric mucous membrane. Frerichs states that cane sugar is not inverted even if left in the gastric juice for twelve to thirty-six hours; and Blondlot believes that the sugar undergoes no change while in the stomach. Eichet found That unless he added hydrochloric acid to gastric juice, there was no inversion of cane sugar; and asserts, in explanation of this, that there is really no free hydrochloric acid in the gastric juice.