The individual with decayed teeth, even with unclean teeth, is open to infection of the lungs, tonsils, stomach, glands, ears, nose, and adenoid tissues. Every time food is taken, and at every act of swallowing, germs flow over the tonsils into the stomach. Mouth breathers with teeth in this condition cannot get one breath of uncontaminated air, for every breath becomes infected with poisonous emanations from the teeth. Bad teeth are frequently the sole cause of bad breath and dyspepsia, and can convey to the system tuberculosis of the lungs, glands, stomach, or nose, and many other transmissible diseases. They may also cause enlarged tonsils and ear trouble. Apart from decomposing food and stagnant septic matter from saliva injured by indigestion, and by sputum which collects in the healthy mouth, there are in many infected mouths pus, exudations from the irritated and inflamed gum margins, gaseous emanations from decaying teeth, putrescent pulp tissue, tartar, and chemical poisons. Every spray from such a mouth in coughing, sneezing, or even talking or reading, is laden with microbes which vitiate the air to be breathed by others. Indigestion from imperfect mastication and imperfect salivation (themselves often due solely to bad teeth) is far less serious than indigestion from germ infection. Germs taken into the stomach can so change the composition of saliva (a natural disinfectant when healthy) as to render it no longer able to kill germs. Indigestion may result in excess of uric acid and toxic material, so that the individual becomes subject to gout and rheumatism, which in turn frequently destroy the bony support of the teeth and bring about Riggs's Disease. The last named is a prevalent and disfiguring disease, whose symptom is receding gums. The irritating toxins deposited on the teeth cause inflammation of the tissues at the gum margins. The gums withdraw more and more from sections of the teeth; the poisons get underneath and work back toward the roots; the infection increases and hastens the loosening of the teeth. I know of a man who had all of his teeth extracted at twenty-one years of age, because he was told that this was the only treatment for this disease, which was formerly thought to be incurable. Yet thorough cleansing and removal of this matter from under the edges of the gums, disinfection, a few visits to the dentist, will stop the recession but cannot regain lost ground. Among those who regularly use the toothbrush, instinct, comfort, or display is the ruling motive, while a small percentage have evolved to the anti-nuisance stage, where the aesthetic standard of their group forbids any member to neglect his teeth. The anti-slum and pro-slum motives for mouth cleanliness and dental sanitation have been awakened in but one or two places. A significant pro-slum activity is the dental clinic organized by forty volunteer dentists, acting for an industrial school maintained by the New York Children's Aid Society.