*Quantity of Food.*—Overeating and undereating are both objectionable from a hygienic standpoint. Overeating, by introducing an unnecessary amount of food into the body, overworks the organs of digestion and also the organs of excretion. It may also lead to the accumulation of burdensome fat and of harmful wastes. On the other hand, the taking of too little food impoverishes the blood and weakens the entire body. As a rule, however, more people eat too much than too little, and to quit eating before the appetite is fully satisfied is with many persons a necessary precaution. The power of self-control, valuable in all phases of life, is indispensable in the avoidance of overeating. *Frequency of Taking Food.*—Eating between meals is manifestly an unhealthful practice. The question has also been raised as to whether the common habit of eating three times a day is best suited to all classes of people. Many people of weak digestive organs have been benefited by the plan of two meals a day, while others adopt the plan of eating one heavy meal and two light ones. Either plan gives the organs of digestion more time to rest and diminishes the liability of overeating. On the other hand, those doing heavy muscular work can hardly derive the energy which they need from less than three good meals a day. Though no definite rule can be laid down, there is involved a hygienic principle which all should follow: _Meals should not overlap_. The stomach should be free from food taken at a previous meal before more is introduced into it. When this principle is not observed, material ferments in the stomach, causing indigestion and other disorders. It should be noted, however, that the overlapping may be due to overeating as well as to eating too frequently. *Dangers from Impure Food.*—Food is frequently the carrier of disease germs and for this reason requires close inspection (page 128). Typhoid fever, a most dangerous disease, is usually contracted through either impure food or impure water (Chapter XXIII). One safeguard against disease germs, as stated above, is thorough cooking. Too much care cannot be exercised with reference to the water for drinking purposes. Water which is not perfectly clear, which smells of decaying material, or which forms a sediment on standing is usually not fit to drink. It can, however, be rendered comparatively harmless by boiling. The objections which many people have to drinking boiled water are removed when it is boiled the day before it is used, so as to give it time to cool, settle, and replace the air driven off by the boiling.