entirely plausible, if we assume that what the man loses is the gratification he might have by spending his dollar, and that what he gains is the benefit of spending it and its accumulation of interest at the end of the year. The assumption is that the man proposes at a certain future date to spend the principal or the capital which he acquires by saving in the present, together with whatever it may have earned as interest; that he measures the personal benefit which he can get by this spending, and finds the larger benefit better worth a fixed sacrifice in the present than a small one. _The Actual Purpose of Abstinence._--Most capital is saved with no expectation of ever spending the principal. The motive is a perpetual income, which the capital will earn. What the man appraises in his own mind is not the personal benefit he can get by spending a dollar and five cents at the end of the year; it is the benefit that will come from spending five cents at the end of the first year, another five cents at the end of a second, and a more or less similar amount at the end of every year that shall follow. It is a perpetual income, and as the man's life is limited, the greater part of it must accrue to others than himself. The satisfaction which he will get from it near the close of his own life comes altogether from the prospect of passing the principal unimpaired to others and in assuring to them and to their successors the perpetual income which the foundation yields. Even on this basis it might be supposed that a large perpetual income would offer a greater inducement to save than a small one, and therefore that the amount of saving would be greater when the rate of interest was higher. This would be true if the importance of the perpetual income could be estimated in this simple way by the mere amount of it.