History, then, is replete with instances, memorable instances, of people, both men and women, who have accomplished things at an age--who have even begun and carried through to successful completion things at an age that would seem to thousands of others, in the captivity of age, with their backs to the future, ridiculous even to think of accomplishing, much less of beginning. On account of a certain law that has always seemed to me to exist and that I am now firmly convinced is very _exact_ in its workings, I have been interested in talking with various ones and in getting together various facts relative to this great discrepancy in the ages of these two classes of "old" people. Within the year I called upon a friend whom, on account of living in a different portion of the country, I hadn't seen for nearly ten years. Conversation revealed to me the fact that he was then in his eighty-eighth year. I could notice scarcely a change in his appearance, walk, voice, and spirit. We talked at length upon the various, so-called, periods of life. He told me that about the only difference that he noticed in himself as compared with his middle life was that now when he goes out to work in his garden, and among his trees, bushes, and vines--and he has had many for many years--he finds that he is quite ready to quit and to come in at the end of about two hours, and sometimes a little sooner, when formerly he could work regularly without fatigue for the entire half day. In other words, he has not the same degree of endurance that he once had. Among others, there comes to mind in this connection another who is a little under seventy. It chances to be a woman. She is bent and decrepit and growing more so by very fixed stages each twelvemonth. I have known her for over a dozen years. At the time when I first knew her she was scarcely fifty-eight, she was already bent and walked with an uncertain, almost faltering tread. The dominant note of her personality was then as now, but more so now, fear for the present, fear for the future, a dwelling continually on her ills, her misfortunes, her symptoms, her approaching and increasing helplessness. Such cases I have observed again and again; so have all who are at all interested in life and in its forces and its problems. What is the cause of this almost world-wide difference in these two lives? In this case it is as clear as day--the mental characteristics and the mental habits of each.