IMPULSIVE INSANITY is perhaps more properly called instinctive monomania, as the morbid impulse is usually shown in only one insane propensity at a time. Like moral insanity, its manifestations are commonly periodic, or at least alternating. Under the name of emotional insanity it furnishes sympathetic juries with an excuse for finding not guilty of murder women who kill their betrayers and husbands who shoot a wife's seducer. It is a not uncommon symptom in a considerable proportion of the persons suffering from the various forms of insanity. As a separate disease it is quite rare, and includes those persons whose insanity is manifested, as Marc says, by what they do rather than by what they say. The insane impulse does not come from any logical process. It is rarely provoked by or associated with a criminal motive, except in an analogous way to the production by excitement of an epileptic attack, to which, indeed, it offers some points of similarity. There would be reason to doubt the existence of the disease unless other indications of mental degeneration were present, especially where there is proof of a criminal motive or where the criminal act and the prisoner's statements are the sole evidence of unsoundness of mind. Unconsciousness, even temporary, and loss of memory, are not symptoms of instinctive monomania. On the contrary, the mind is quite clear, and resists successfully the insane impulse so long that the person affected with it has often gained confidence that he will never yield to it; and he soon learns the fact that, there being in circumstances external to himself no reason for the crime suggested to the mind with such force, temptations do not occur to the act. While the impulse lasts a great variety of distressing mental symptoms accompany it, so intense that the impulse often cannot be resisted, and then the terrible brain-tension is relieved. I doubt whether hallucinations of hearing are found in impulsive insanity, and incline to think that all the reported cases where crimes of impulse have been committed in obedience to a voice commanding the individual to do this or that act of violence are more properly classified under other forms of mental disease. One kind of instinctive monomania sometimes disappears to be replaced by another. In developing boys and girls there is not seldom a pathological mental state during which lying, stealing, running away from home, etc. are common for several months or a few years; but this is a curable condition, and does not by any means necessarily end in instinctive monomania.