_Folie du doute._--Among men of genius we often find the phenomena which characterizes that disorder termed by alienists _folie du doute_, one of the varieties of melancholia. In this form of insanity the subject has every appearance of mental health; he reasons, writes, and speaks like other people; everything goes well until he has to execute a definite action, and in this he finds all sorts of imaginary dangers. Thus I have treated a woman who when she had to get up in the morning, would hesitate for hours beside her bed, with one arm in the sleeve of her chemise, and the other sleeve hanging down, until her husband came to her help. Sometimes the husband was obliged to give her a few slight blows to induce her to take action. If she went for a walk and knocked against a stone, or came across a puddle, she would remain motionless; her husband had then to carry her for a few instants. In conversation she seemed the best and most sensible of mothers, but woe to the unfortunate person who dropped any word she regarded with suspicion, such as “devil,” “death,” “God”; she immediately seized him and cried out, until he repeated a certain formula, declaring a dozen times that the word had not been uttered to injure her. A peasant, affected by the same disorder, was incapable of attending to his work, unless some one was there to watch over him; for, said he, “I cannot make up my mind whether I ought to dig or to hoe, to go to the field or to the hill, and my uncertainty is so great that I end by doing nothing.”