In reality, the notion of lunatic has lost its former superstitious signification and it has taken no precise medical signification. That word is now the term of the police language. It indicates only an embarrassment felt by the police before certain persons’ conduct. When an individual shows himself to be dangerous for others, the public administration has the habit of defending us against him by the system of threats and punishments. As a rule, in fact, when a normal mind is in question, threats can stop him before the execution of crime, and punishments, when crime has been committed, can prevent him from beginning again; that is the psychological fact which has given birth to the idea of responsibility. But in certain disorders it becomes evident that neither threats nor punishments have a favorable effect, for the individual seems to have lost the phenomenon of responsibility. When an individual shows himself to be dangerous for others or for himself, and that he has lost his responsibility, we can no longer employ the ordinary means of defense; we are obliged to defend ourselves against him, and defend him against himself by special means which it is useless to apply to other men; we are obliged to modify legal conduct toward him. All disorders of the mind oblige us to modify our social conduct toward the patient, but only in a few cases are we obliged to modify at the same time our legal conduct; and these are the sort of cases that constitute lunacy.
This important difference in the police point of view is of no great importance in the psychological point of view nor in the medical point of view, for the danger created by the patient is extremely varied. It is impossible to say that such or such a disorder defined by medicine leaves always the patient inoffensive and that such another always renders him dangerous. There are melancholies, general paralytics, insane who are inoffensive, and whom one should not call lunatics; there are impulsive psychasthenics who are dangerous and whom one shall have to call lunatics. The danger created by a patient depends a great deal more upon the social circumstances in which he lives than upon the nature of his psychological disorders. If he is rich, if he has no need to earn his living, if he is surrounded by devoted watchfulness, if he lives in the country, if his surroundings are simple, the very serious mental disorders he may have do not constitute a danger. If he is poor, if he has to earn his living, if he lives alone in a large town