Practical physiology for the use of schools and families / by Edward Jarvis.

  • Jarvis, Edward, 1803-1884.
Date:
1848
Catalogue details

Licence: Public Domain Mark

Credit: Practical physiology for the use of schools and families / by Edward Jarvis. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    render some assistance in the work of digestion. All these organs together form the digestive apparatus, which is com- plete and perfect in itself; nothing is wanting for the work, and there is nothing unnecessary. Each one of these organs, or parts of organs, has a separate and distinct part to perform in the work of converting food into the nutriment of the blood. 7. The mouth is the first and only visible organ of digestion, ^and first receives the food from our hands and our tables. It is composed of several parts, all of which are employed in the preparatory work of digestion. The lips and the cheeks form the outward walls of the mouth, and retain the food after it is received. The teeth serve to divide and break down the morsel to a fineness suitable to the stomach. The tongue rolls the morsel about, and keeps it in its place be- tween the teeth, while it is undergoing the process of masti- cation or chewing. 8. The object of the process of mastication is. twofold — to divide the food, and grind it to such minute portions as to fit it for digestion in the stomach ; and also to mix it with the fluids of the mouth, so that these together may form a pulp. In the first of these processes the teeth play the principal part, and in the second the salivary glands. The tongue aids both. 9. The tatli are the most prominent organs in the mouth. They differ in various animals, according to the food upon which they live. The carnivorous or flesh-eating animals have teeth fitted for seizing upon their prey, and for cutting up flesh. -Hence they have sharp cutting or front teeth; and long, sharp and pointed canine or stomach and eye teeth ; and grinders, with high and sharpened points, by which they chew or masticate their fleshy food with facility. The her- bivorous or vegetable-eating animals have short, blunt, and stroncr front or incisor teeth, by which they break off their food, either grass or foliage. As they seize no prey, they have no use for the sharp canine or stomach and eye teeth; therefore these teeth are very small, and in some scarcely seen; but their molar or grinding teeth are very large, broad,