greatest genius cannot understand the nature of all men at the same time, on one and the same day. The comprehensive and manifold rudiments which a man possesses in his mind can develop only slowly and by degrees with the gradual unfolding of his whole life. It appears almost as if there were a definite periodicity in his development. These periods, when they recur, however, are not exactly alike; they are not mere repetitions, but are intensifications of their predecessors, on a higher plane. No two moments in the life of an individual are exactly alike; there is between the later and the earlier periods only the similarity of the higher and lower parts of a spiral ascent. Thus it has frequently happened that famous men have conceived a piece of work in their early youth, laid it aside during manhood, and resumed and completed it in old age. Periods exist in every man, but in different degrees and with varying "amplitude." Just as the genius is the man who contains in himself the greatest number of others in the most active way, so the amplitude of a man's periods will be the greater the wider his mental relations may be. Illustrious men have often been told, by their teachers, in their youth "that they were always in one extreme or another." As if they could be anything else! These transitions in the case of unusual men often assume the character of a crisis. Goethe once spoke of the "recurrence of puberty" in an artist. The idea is obviously to be associated with the matter under discussion.
It results from their periodicity that, in men of genius, sterile years precede productive years, these again to be followed by sterility, the barren periods being marked by psychological self-depreciation, by the feeling that they are less than other men; times in which the remembrance of the creative periods is a torment, and when they envy those who go about undisturbed by such penalties. Just as his moments of ecstasy are more poignant, so are the periods of depression of a man of genius more intense than those of other men. Every great man has such periods, of longer or shorter duration, times in which he loses self-confidence,
