The period from about twenty to thirty is usually the most momentous in the lives of illustrious men and women. It is true that the most abiding impressions, those which the future author will reproduce most vividly, have been absorbed by the growing brain previous to this age; but the fusion of these varied impressions of the outward world with the inner life, and the endless combinations in which imagination delights, rarely begin before. Then, as a rule, the ideas are engendered to be carried out in the maturity of life. Alfred de Vigny says truly enough:

Moreover, it is a revolutionary age. Inherited opinions that had been accepted, as the rotation of the seasons, with unhesitating acquiescence, become an object of speculation and passionate questioning. Nothing is taken upon trust. The intellect, stimulated by the sense of expanding and hitherto unchecked capacity, delights in exercising its strength by critically passing in review the opinions, laws, institutions commonly accepted as unalterable. And if the intellect is thus active the heart is still more so. This is emphatically the time of enthusiastic friendship and glowing love, if often also of cruel disenchantment and disillusion. In most biographies, therefore, this phase of life is no less fascinating than instructive.