SALIVA

or spittle, is a fluid pits three pairs of salivary glands situated below the chin in front of the ear. Saliva consists of water, salts, and an active ingredient which changes the starch in bread, potatoes, etc., to sugar. Saliva is e ential both for swallowing and speaking, owing to its lubricating effect. It is alkaline in reaction. Tho salts are e to be pa oa on the teeth in the form of tartar. The quantity of saliva secreted varices. The sight or odour of sath | food makes the mouth “ water"; and tho presence of food in the mouth causes a similar increased flow. Acids increase the flow. Hence lemonade or an acid-drop relieve a parched throat. All pungent substances, e.g., mustard, ginger and tobacco increase the flow.. Certain drugs continued over long periods may cause troublesome salivation, especially mercury. Irritants in the mouth act in the same way, the baby that is oat is a familiar case. Hence, those taking mercury shou pay special attention to the teeth and abstain from strong tobacco, so as to avoid two po ible stimulants to salivation. The flow of saliva is checked by alkaline Gareies, by bell a- F donna, and by removal of all sources of irritation from ‘ mouth and stomach. It may also bo checked by fear. f In the East a thicf is at times said to be detected by ae, all the suspected men eat a mouthful of rice. The P is supposed to be unable to swallow from lack of saliva. [s. 403]