Let us briefly review some common types of hysterical disability,--taking as our first guide Dr. Pierre Janet's admirable work, _L'Etat Mental des Hystériques_ (Paris, 1893).
What, then, to begin with, is Dr. Janet's general conception of the psychological states of the advanced hysteric? "In the expression _I feel_," he says (_L'Etat Mental_, p. 39), "we have two elements: a small new psychological fact, 'feel,' and an enormous mass of thoughts already formed into a system 'I.' These two things mix and combine, and to say _I feel_ is to say that the personality, already enormous, has seized and absorbed this small new sensation; ... as though the _I_ were an amoeba which sent out a prolongation to suck in this little sensation which has come into existence beside it." Now it is in the assimilation of these elementary sensations or affective states with the _perception personnelle_, as Janet terms it, that the advanced hysteric fails. His field of consciousness is so far narrowed that it can only take in the minimum of sensations necessary for the support of life. "One must needs have consciousness of what one sees and hears, and so the patient neglects to perceive the tactile and muscular sensations with which he thinks that he can manage to dispense. At first he could perhaps turn his attention to them, and recover them at least momentarily within the field of personal perception. But the occasion does not present itself, and the _psychological bad habit_ is formed.... One day the patient--for he is now veritably a patient--is examined by the doctor. His left arm is pinched, and he is asked whether he feels the pinch. To his surprise the patient realises that he can no longer feel consciously, can no longer bring back into his personal perception sensations which he has neglected too long--he has become anæsthetic.... Hysterical anæsthesia is thus a fixed and perpetual distraction, which renders its subjects incapable of attaching certain sensations to their personality; it is a restriction of the conscious field."
The proof of these assertions depends on a number of observations, all of which point in the same direction, and show that hysterical anæsthesia does not descend so deep into the personality, so to say, as true anæsthesia caused by nervous decay, or by the section of a nerve.