A complete and adequate notion of life can never be attained by any one who does not reach old age; for it is only the old man who sees life whole and knows its natural course; it is only he who is acquainted--and this is most important--not only with its entrance, like the rest of mankind, but with its exit too; so that he alone has a full sense of its utter vanity; whilst the others never cease to labor under the false notion that everything will come right in the end. On the other hand, there is more conceptive power in youth, and at that time of life a man can make more out of the little that he knows. In age, judgment, penetration and thoroughness predominate. Youth is the time for amassing the material for a knowledge of the world that shall be distinctive and peculiar,--for an original view of life, in other words, the legacy that a man of genius leaves to his fellow-men; it is, however, only in later years that he becomes master of his material. Accordingly it will be found that, as a rule, a great writer gives his best work to the world when he is about fifty years of age. But though the tree of knowledge must reach its full height before it can bear fruit, the roots of it lie in youth. Every generation, no matter how paltry its character, thinks itself much wiser than the one immediately preceding it, let alone those that are more remote. It is just the same with the different periods in a man's life; and yet often, in the one case no less than in the other, it is a mistaken opinion. In the years of physical growth, when our powers of mind and our stores of knowledge are receiving daily additions, it becomes a habit for to-day to look down with contempt upon yesterday. The habit strikes root, and remains even after the intellectual powers have begun to decline,--when to-day should rather look up with respect to yesterday. So it is that we often unduly depreciate the achievements as well as the judgments of our youth. This seems the place for making the general observation, that, although in its main qualities a man's _intellect_ or _head_, as well as his _character_ or _heart_, is innate, yet the former is by no means so unalterable in its nature as the latter. The fact is that the intellect is subject to very many transformations, which, as a rule, do not fail to make their actual appearance; and this is so, partly because the intellect has a deep foundation in the physique, and partly because the material with which it deals is given in experience. And so, from a physical point of view, we find that if a man has any peculiar power, it first gradually increases in strength until it reaches its acme, after which it enters upon a path of slow decadence, until it ends in imbecility. But, on the other hand, we must not lose sight of the fact that the material which gives employment to a man's powers and keeps them in activity,--the subject-matter of thought and knowledge, experience, intellectual