Saliva

(saliva, so called @ salino sapore from its salt taste, or perhaps from ciarog, spits tle.) The fluid which is secreted by the salivary glands into the cavity of the mouth. The secretory organ is composed of three pair of salivary glands. 1. The parotid glands, which evacuate their saliva by means of the Sten on i an duct behind the middle dens molar is of the upper jaw. 2. The submaxillary glands, which pour out their saliva through theW arthonian ducts on each side of the frenulum of the tongue by a narrow osculum. 3. The sub lingular glands, situated between the internal surface of the maxilla and the tongue, and pour out their saliva through numerous River i an ducts at the apex of the tongue. The saliva in the cavity of the mouth has mixed with it, 1. The mucus of the mouth, which exhales from the labial and genal glands. 2. A roscid vapour, from the whole surface of the cavity of the mouth. The saliva is continually swallowed with, or without masticated food, and some is also spit out. It has no cojour nor smell; it is tastele , although it contains a little salt, to which the nerves of the tongue are accustomed, Its specific gravity is somewhat greater than water. Its consistence is rather plastic and spumous, from the entangled atmospheric air. The quantity of twelve pounds is supposed to be secreted in twelve hours. During mastication and speaking the secretion is augmented, from the mechanical pre ure of the muscles upon the salivary glands. Those who are hungry secrete a great quantity, from the sight of agreeable food. It is imperfectly di olved by water; somewhat coagulated by alkohol of wine; and is congealed with more difficulty than water. is Inspi ated by a small dose, and di olved in a large dose, of mineral acids. It is also soluble in aerated alkali. Caustic alkali and quick lime extract volatile alkali from saliva. cotrodes copper and iron, and precipitates silver and lead in the form of corneous luna. a ists the spirituous fermentation of farinaceous substances; hence barbarous nations prepare an inebriating drink from the chewed roots of the jatropha manihot and piper met hist i cum. It po e es an antiseptic virtue, according to the experiments of the celebrated Pringle. It easily becomes putrid in warm air, and gives off volatile alkali. Constituent principles.—Saliva appears to consist of water, albumen, am me on i a cal salt, and animal earth. ~Of water, there is 4 given out by distillation. The albumen is detected by alkohol of wine. The ammoniacal salt is demonstrated by triturating quick Jime with saliva; and'the animal earth from salival calculus, and the products of fire. The use of the saliva is, 1. It augments the taste of the food, by the evolution of sapid matter. 2, During mastication, it mixes with, di olves, and resolves into its principles, the food; and changes it into a _pultaceous ma , fit to be swallowed; hence it.commences chymification. 3. It moderates thirst, by moistening the cavity of the mouth and fauces.