Thorough mastication is important, not only because the chemical action on the starch molecules is facilitated by the softening and mixing with the saliva, but also because thorough mastication tends to prevent overeating—the appetite is more quickly satisfied when the food is well masticated. Cool water encourages the flow of saliva and for this reason should be drunk before meals, particularly when digestion is weak. It may be taken at rest periods during the meal. (See page 31.) * * * * * [Sidenote: The Mouth and Nasal Passages] The relation of the mouth and nasal passages to the digestive processes is seldom considered by the average individual. Their importance to the growing child is being recognized by the examination of school children which is now being made a part of the health program in many of our cities. Their importance to the adult is no less. Food particles allowed to remain around the teeth, or in the cavities of decayed teeth, incite bacterial action. With the next meal these bacteria are swallowed and cause fermentation of the food, occasioning indigestion, and possibly, dyspepsia. Decayed or missing teeth, swollen gums, or pyorrhea, interfere with proper mastication of food, hence it does not receive the thorough salivary moistening necessary; the starches pass practically unchanged into the stomach and small intestine, overburdening these organs. Catarrh of the nasal passages, with the constant swallowing of germ-filled secretions, carries morbid products into the stomach, coating the glands with mucus, often infecting them; it may also occasion a catarrhal condition of that organ. If, from any cause, the saliva becomes acid, dryness of the mouth results and desire for food is lessened or absent. Diseases of the salivary glands may render these necessary secretions unfit to perform their work. In illness the mouth often drops open from weakness, producing the same condition of dryness. The mouth, in illness, is too often neglected by those in charge of the invalid. Adenoids and enlarged turbinates in child or adult, narrowing the nasal passages and preventing the ingress of air, cause mouth breathing. The air dries the membranes and the tongue becomes swollen and cracks, interfering with proper mastication. Adenoids should be removed, and any other condition which interferes with the proper function of the mouth should be remedied as soon as possible. The mouth should be properly cleansed, the gums massaged, the teeth thoroughly brushed, back as well as front, defective teeth repaired or removed, abnormal growths eliminated, and the secretions kept abundant and healthy. Food well prepared in the mouth by thorough mastication satisfies hunger, renders more easy the work of the stomach and intestines, and aids in the general welfare of the system. * * * * * [Sidenote: Gum-chewing]