Foods and dietaries : a manual of clinical dietetics / by R.W. Burnet.

  • Burnet, R. W.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: Foods and dietaries : a manual of clinical dietetics / by R.W. Burnet. Source: Wellcome Collection.

    22/256 (page 6)
    mote or retard the action of the gastric juice upon it. The greater the amount of surface that is presented to the action of the gastric juice, the more quickly will solution take place. Hence tough, doughy substances, that cling in masses, and firm, unbroken fibres, whether of animal or vegetable tissue, longer resist solution in the gastric juice than friable, minutely divided particles. It need hardly, therefore, be pointed out that thorough mastication of food is of the utmost importance, since by that means minute subdivision is secured, and consequently a vastly increased surface-area is presented for the action of the gastric juice. Moreover, in the case of carbo-hydrates, in addition to the mechanical effects of prolonged mastication, their digestion is begun in the mouth, by the action of the saliva converting them into dextrin. In speaking of the appearance of the healthy gastric mucous membrane, it was implied that the stomach when empty and contracted is at rest. On the introduction of food, however, or when the stomach is stimulated in other ways, certain movements are set up. On the first entrance of food into the stomach there are but feeble indications of movement; hence it is evidently not the fact of the stomach being filled that causes the movements. If that were the cause, they would be greatest at the beginning, whereas observations show that they increase and become more marked as digestion proceeds, till they attain a rhythmic, churning action. The movements, therefore, are clearly an essential part of digestion, and are not due to any mere mechanical cause. By these regular movements fresh portions of the food are brought under the action of the gastric juice. In health, as has been already pointed out, a dietary is suitable or well-balanced when it is properly adapted to the wants of the individual, and contains a due proportion of nitrogenous elements, of carbo-hydrates, of fats, and of salines, with water. Clinically, however, the definition does