The psychical condition of men's minds may be compared with a set of bells close together, and so arranged that in the ordinary man a bell rings only when one beside it sounds, and the vibration lasts only a moment. In the genius, when a bell sounds it vibrates so strongly that it sets in action the whole series, and remains in action throughout life. The latter kind of movement often gives rise to extraordinary conditions and absurd impulses, that may last for weeks together and that form the basis of the supposed kinship of genius with insanity.

pp. 122-123. - Sex and Character (1903)