CANCER.--The cause of cancer is not known. All the evidence, however, goes to show that it is neither communicable nor hereditary. Cancer may occur on the skin, stomach, or other organs; in women it most commonly occurs in the breast or uterus (womb). In both sexes it occurs most frequently after 40 years of age. No known medicine will cure cancer; salves and ointments have no effect. Radium and _x_-ray should not be relied upon if the cancer can be removed by operation. Safety consists in removing the growth entirely, and complete removal is possible only in the early stages. Early diagnosis is consequently of the greatest possible importance, and an examination can do no harm in any case. Warts and moles on the skin may develop into cancer, and should be removed if they show signs of irritation. Loss of appetite and weight, any disturbance of the stomach or intestines, and sores that refuse to heal should lead a person to consult a physician; the same is true of any lump in the breast, and of irregular or persistent bleeding from the uterus in women over forty. The fact that pain is not present in cancer until the late stages leads many persons to neglect the trouble until it is too far advanced for operation. Time is all-important; hope depends on operation in the early stages when there is a very great probability of permanent cure. MENTAL ILLNESS.--Insanity, like cancer, is increasing. Like both cancer and tuberculosis, hope lies in prevention and early treatment; and like them both, in its early symptoms it is too often unrecognized or neglected. Many people are surprised to learn that known, avoidable causes are responsible for the condition of about 50% of the insane patients now under treatment. Chief among these known causes is a communicable germ disease called syphilis, to which is due the disease called paresis, or "softening of the brain." About 25% of patients admitted to hospitals for the insane are there from the effects of habitual use of alcohol, even in "moderate" quantities. Other cases of insanity result from diseases of the heart, arteries, and kidneys, and still others have been traced to the poisons of tuberculosis, typhoid, diphtheria, and other communicable diseases. Prevention of insanity caused by these diseases depends upon prevention or complete cure of the diseases themselves. Still other causes of insanity are known. Hereditary nervous weakness may predispose to insanity, and for such persons, those whose nervous resistance is naturally not very great, the stress of living may prove too much. Mental breakdowns are rarely caused by overwork unless accompanied by worry or bad hygienic conditions, but they result not infrequently from bad mental habits.