The early decades of age--The deadline of seventy--The patheticism of the old--The attitude of physicians toward them--Fluctuations of youth--Erotic decline--Alternations in the domain of sleep, food, mood, irritability, rational self-control, and sex--The dawn of old age in women--Dangers of the disparity when December weds May--Sexual hygiene for the old--Mental effects of the dulling of sensations--Lack of mental pabulum--The _tedium vitae_--Changes in the emotional life--Age not second childhood--Women in the dangerous age--Need of a new and higher type of old age--Aristotle’s golden mean and the magnanimous man--The age of disillusion--Increased power of synthesis--Nature’s balance between old and young--The eternal war between them--Superior powers of the old in perspective and larger views--New love of nature and the country--Their preëminence in religion, politics, philosophy, morals, and as judges--Looking within and without--Merging with the cosmos--The three ways of escaping the decay of civilization. To learn that we are really old is a long, complex, and painful experience. Each decade the circle of the Great Fatigue narrows around us, restricting the intensity and endurance of our activities. In the thirties the athletic power passes its prime, for muscular energy begins to abate. There is also some loss of deftness, subtlety, and power of making fine, complex movements of the accessory motor system, and a loss of facility for acquiring new skills. In the forties grayness and, in men, baldness may begin and eyesight is a little less acute so that we hold our book or paper farther off. We are less fond of “roughing” it or of severe forms of exercise. We may become so discontented with our achievements or our environment that we change our whole plan of life. In the fifties we feel that half a century is a long time to have lived and compare our vitality with that of our forbears and contemporaries of the same age. Memory for names may occasionally slip a cog. We go to the physician for a “once over” to be sure that all our organs are functioning properly. We realize that if we are ever to accomplish anything more in the world we must be up and at it and give up many old hopes and ambitions as vain. Perhaps we indulge ourselves in certain pleasures hitherto denied before it is forever too late. At sixty we realize that there is but one more threshold to cross before we find ourselves in the great hall of discard where most lay their burdens down and that what remains yet to do must be done quickly. Hence this is a decade peculiarly prone to overwork. We refuse to compromise with failing powers but drive ourselves all the more because we are on the home stretch. We anticipate leaving but must leave things right and feel we can rest up afterwards. So we are prone to overdraw our account of energy and brave the danger of collapse if our overdraft is not honored.