Practical physiology, or, Anatomy and physiology applied to health : for the use of schools and families / by Edward Jarvis.

  • Jarvis, Edward, 1803-1884.
Date:
1852
Catalogue details

Licence: Public Domain Mark

Credit: Practical physiology, or, Anatomy and physiology applied to health : 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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    16. The saliva flows, during the process of mastication, in some measure proportionate to the dryness of the food. The salivary glands have a very active sympathy with the appe- tite, and will sometimes send forth a flow of saliva at the mere presence of savory food, so that the common saying, that one's mouth waters at the sight of agreeahle dishes, is physiologically true. These glands are important assist- ants in the masticating process, when they and the body are in health ; but in fevers, and in some other diseases, these organs refuse to act, and the mouth then is dry and parched. 17. By the united operation qf the teeth and the salivary glands, the food is first ground into small particles, and then made into a soft pulp, in the mouth. Both these operations are necessary, for we cannot swallow the morsels unless they are divided and moistened, either naturally or artificially. Let any one attempt to swallow a mouthful of dry bread without chewing, or powdered cracker, without saliva or other fluid to soften it, and he will find, that this process, which, when proper preparation is made for it, is one of the easiest and most agreeable, is now one of the most difficult and unpleasant. If the food be not divided while in the mouth, it cannot be done afterwards; there is no machinery nor power in the stomach to effect this division. 18. In the back part of the mouth is a second chamber called the pharynx, separated from the anterior or front chamber by a movable curtain, called the palate. This curtain, hanging between these two chambers, is easily seen when the mouth is partly opened, and seems then to be the farthest boundary of the cavity. - But when the mouth is stretched widely open, this curtain is raised, and the other chamber is disclosed behind it. A little knob or tongue of flesh hangs down from the middle of the palate, nearly, and sometimes quite, to the tongue, and partially or entirely divides the passage-way from the front to the back chamber. This gives the appearance of two passages, one on the right and the other on the left side. !!). Four passages open out from the back chamber; one