As has already been pointed out, the first, step in digestion is taken in the mouth, and careful chewing is not less important than the other parts of the digestive process. If one's teeth are not adapted to chewing, if they are bunched, crowded, loose, or isolated, the appearance of the teeth is the least objectionable feature. The real importance comes from the fact that with such teeth perfect mastication is impossible. The teeth themselves harbor germs which actually infect the food and favor its putrefaction. With decayed teeth, infectious diseases find a ready entrance to the lungs, nostrils, stomach, glands, ears, nose, and membranes. At every act of swallowing, germs are carried into the stomach. Mouth breathers cannot get one breath of uncontaminated air, and dental clinics, organized and conducted in the interests of the health of school children, have been altogether too little inaugurated. The use of a toothbrush should be encouraged in children as soon as they are four years old, and its habitual use twice a day is most desirable for every one. Only regular examination by the dentist can keep the teeth in good condition, and periodic visits at least once a year to a dentist's office, not to the kind advertised by Indians where they are willing to extract teeth without pain, free, but where a regularly qualified dentist practices, should be the habit. Armenian children, who prize and covet beautiful teeth, are taught to clean their teeth always after eating, if only an apple or a piece of bread between meals, and while probably our American customs would hardly make this possible, there is no question but that a persistent and frequent use of the toothbrush will help much in reducing dentist bills. _Sleep._ From many standpoints sleep is the most wonderful attribute of the human body. Our familiarity, from our earliest years, with sleep, closes our eyes to its strange, its awful power. We know that every human being, once in twenty-four hours, will normally close his eyes and for a certain length of time be as oblivious to things present as if already in the sleep of death. It is a common belief that sleep is nature's provision for restoring tired muscles and jaded nerves, and for building up new tissue in cell and corpuscle. Excessive exertion produces a numbness and exhaustion so that the body becomes "dead tired," and sleep brings back life and elasticity. And yet some parts of the body, some muscles and some organs, do not stop work during sleep, and apparently feel no bad results for their continuous lifelong exertion. Thus, the lungs, whose muscular action is estimated at the rate of one thirtieth of a horse power, have no rest day or night, seemingly without weariness. Similarly, the heart is continually forcing blood under a pressure of about three pounds through the arteries without cessation from birth to death.