If one stops physical and mental activity at any age, the vital forces recede, muscles and vital organs become weak and inactive, and the waste of the system is not fully eliminated. Such a man at thirty or forty is physically and mentally older than the man who is in active business or is taking daily vigorous exercise, at seventy or eighty. The latter may follow the same diet which he followed at fifty, while the former should follow the diet of the old man who has stopped active work. Young men who through excessive drafts on their vitality have exhausted their forces often act and look twice their years. For these the diet should be simple, easily digested, and nutritious, and often reduced in quantity. Formerly it was thought that at fifty years of age a man or a woman was on the down-hill slope; they were considered “aged.” Owing to the discoveries of scientific tests of the condition of arteries and vital organs, it is now known that years do not play so large a part in the matter of age. A man or a woman at fifty, who is in vigorous mental and physical health, is in the prime of life, while many from twenty-five to thirty, who have dissipated their vital forces, may be said to have entered the age of decrepitude. The saying, “Man is as old as his arteries,” should be expanded to “Man is as old as his tissues.” People have thought too long that age is a matter of years. They need to be aroused to recognize the fact that the condition of age is a matter of health of body and mind; that the spirit, which sees to it that the body which it inhabits is kept vigorous and strong by healthful and happy thoughts and an active interest in the world’s affairs, is “young,” no matter what the years number. Optimism and cheer keep one young; pessimism and habits of mental depression age one. One of the encouraging signs of the times is that more and more people are learning to know that their activities need not be given up because they have reached a certain age. If the children which formerly needed care, have grown and gone to homes of their own, the activities of the mother and father are freed to find vent in other directions. If children no longer need immediate care, the parents have time to make better conditions for the children of others less fortunate. They should interest themselves in public questions that affect these children and their own, indirectly if not directly. New life and strength have been found by many by changing their activities and keeping the thoughts young and the interest vivid. The body will respond marvelously to the mandates of the inner self. * * * * * [Sidenote: Habit and Regularity of Eating] There is no doubt that the _habit_ of eating governs one’s convictions of what the system requires. One is inclined to think that a desire for a food is a requirement of Nature; yet it may simply be the continuation of a habit due to indigestion.