Contributions to the physiology of digestion and to dietetics.

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

Licence: In copyright

Credit: Contributions to the physiology of digestion and to dietetics. Source: Wellcome Collection.

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

    15/154 (page 5)
    This solution was made by dissolving 200 grammes of pure dry cane sugar in distilled water and diluting to one litre. After being kept at this temperature for one hour, invert sugar amount- ing to 019 per cent, was produced. At the end of two hours this had increased to 0252 per cent. This constitutes the control experiment, and shows the amount of inversion which a 20 per cent, solution of cane sugar undergoes after one and two hours' exposure to the normal temperature of the body. To determine whether saliva had a greater inversive action on cane sugar than distilled water, I performed the following experi- ment :— Equal volumes of human saliva and cane sugar solution (of strength equal to 40 per cent.) were mixed together to give a 20 per cent, solution of sugar. Several beakers containing this solu- tion were placed in the water bath at 38° C. After thirty minutes no recognisable inversion had occurred. In forty-five minutes traces of invert sugar appeared, as shown by the reduction of copper oxide, and in one hour the invert sugar amounted to 0'2 per cent.; while in two hours it reached 0'27 per cent. I. Cane Sugar, 20 per cent, at 38° C. Invert Sugar. In one hour. In two hours. 1. Solution in distilled water, . 2, „ „ saliva, .... Difference, .... 019% 0-2 ^° 0-252/' 0-27 ^° •01 •018 The amount of inversion in presence of saliva is so nearly the same as in its absence, that we may safely conclude that normal human saliva has practically no influence in hastening or retarding the inversion of cane sugar. In fact, it seems to be perfectly passive in this respect. The results given in the above experiment ■were practically identical with those obtained in other experiments conducted on similar lines, II. Gastkic Digestion of Cane Sugar. Cane sugar reaches the stomach unchanged. Does it undergo any digestion in this organ, or does it require any ? It is thought by some that cane sugar is absorbed unchanged, and that'after its entrance into the portal vessels it is transformed into glucose through the agency of a ferment in the blood. Pavy is of opinion that it does not require to be changed by digestion to aid its absorption, but merely requires solution to enable it to pass into the bloodvessels. He is inclined to believe, however, that, as a matter of fact, it is at all events partially converted