The fixed idea, thus originating, may develop in different ways. It may become a centre of explosion, or a nucleus of separation, or a beginning of death. It may induce an access of hysterical convulsions, thus acting like a material foreign body which presses on a sensitive part of the organism. Or it may draw to its new parasitic centre so many psychical elements that it forms a kind of secondary personality, co-existing secretly with the primary one, or even able at times (as in some well-known cases) to carry the whole organism by a coup-de-main. (Such changes, it may be noted in passing, are not always for the worse.) Or, again, the new quasi-independent centres may be merely anarchical; the revolt may spread to every cell; and the forces of the environment, ever making war upon the organism, may thus effect its total decay.

Let us dwell for a few moments on the nature of these fixed or insistent ideas. They are not generally or at the first outset extravagant fancies,—as that one is made of glass or the like. Rather will "fixed ideas" come to seem a mere expression for something in a minor degree common to most of us. Hardly any mind, I suppose, is wholly free from tendencies to certain types of thought or emotion for which we cannot summon any adequate check—useless recurrent broodings over the past or anxieties for the future, perhaps traces of old childish experience which have become too firmly fixed wholly to disappear. Nay, it may well be that we must look even further back than our own childhood for the origin of many haunting troubles. Inherited tendencies to terror, especially, seem to reach far back into a prehistoric past. In a recent "Study of Fears," which Professor Stanley Hall has based on a wide statistical collection,[8] it would seem that the fears of childhood often correspond to no existing cause for uneasiness, but rather to the vanished perils of primitive man. The fear of darkness, for instance, the fear of solitude, the fear of thunder-storms, the fear of the loss of orientation, speak of primitive helplessness, just as the fear of animals, the fear of strangers, suggest the fierce and hazardous life of early man. To all such instinctive feelings as these a morbid development is easily given.

Of what nature must we suppose this morbid development to be? Does it fall properly within our present discussion? or is it not simply a beginning of brain-disease, which concerns the physician rather than the psychologist? The psychologist's best answer to this question will be to show cases of fixed ideas cured by psychological means.[9] And indeed there are few cases to show which have been cured by any methods except the psychological; if hypnotic suggestion does not succeed with an idée fixe, it is seldom that any other treatment will cure it. We may, of course, say that the brain troubles thus cured were functional, and that those which went on inevitably into insanity were organic, although the distinction between functional and organic is not easily demonstrable in this ultra-microscopic realm.

At any rate, we have actually on record,—and that is what our argument needs,—a great series of idées fixes, of various degrees of intensity, cured by suggestion;—cured, that is to say, by a subliminal setting in action of minute nervous movements which our supraliminal consciousness cannot in even the blindest manner manage to set to work. Some such difference as exists on a gross scale between striped and unstriped muscle seems to exist on a minute scale among these smallest involved cells and fibres, or whatever they be. Some of them obey our conscious will, but most of them are capable of being governed only by subliminal strata of the self.

If, however, it be the subliminal self which can reduce these elements to order, it is often probably the subliminal self to which their disorder is originally due. If a fixed idea, say agoraphobia, grows up in me, this may probably be because the proper controlling co-ordinations of thought, which I ought to be able to summon up at will, have sunk below the level at which will can reach them. I am no longer able, that is to say, to convince myself by reasoning that there is no danger in crossing the open square. And this may be the fault of my subliminal self, whose business it is to keep the ideas which I need for common life easily within my reach, and which has failed to do this, owing to some enfeeblement of its grasp of my organism.

If we imagine these obscure operations under some such form as this, we get the advantage of being able to connect these insistent ideas in a coherent sequence with the more advanced phenomena of hysteria. We have seen that the presence of insistent ideas implies an instability of the conscious threshold; and this, in its turn, indicates a disorderly or diseased condition of the hypnotic stratum,—of that region of the personality which, as we shall see, is best known to us through the fact that it is reached by hypnotic suggestion.

Now we shall find, I think, that all the phenomena of hysteria are reducible to the same general conception. To understand their many puzzles we have to keep our eyes fixed upon just these psychological notions—upon a threshold of ordinary consciousness above which certain perceptions and faculties ought to be, but are not always, maintained, and upon a "hypnotic stratum" or region of the personality to which hypnotic suggestion appeals; and which includes faculty and perception which surpass the supraliminal, but whose operation is capricious and dreamlike, inasmuch as they lie, so to say, in a debateable region between two rules—the known rule of the supraliminal self, adapted to this life's experience and uses, and the conjectured rule of a fuller and profounder self, rarely reached by any artifice which our present skill suggests. Some of these conscious groupings have got separated from the ordinary stream of consciousness. These may still be unified in the subliminal, but they need to be unified in the supraliminal also. The normal relation between the supraliminal and the subliminal may be disturbed by the action of either.

Let us now see how far this view, which I suggested in the S.P.R. Proceedings as far back as 1892,[10] fits in with those modern observations of hysteria, in Paris and Vienna especially, which are transforming all that group of troubles from the mere opprobrium of medicine into one of the most fertile sources of new knowledge of body and mind.

First, then, let us briefly consider what is the general type of hysterical troubles. Speaking broadly, we may say that the symptoms of hysteria form, in the first place, a series of phantom copies of real maladies of the nervous system; and, in the second place, a series of fantasies played upon that system—of unreal, dreamlike ailments, often such as no physiological mechanism can be shown to have determined. These latter cases are often due, as we shall see, not to purely physiological, but rather to intellectual causes; they represent, not a particular pattern in which the nervous system tends of itself to disintegrate, but a particular pattern which has been imposed upon it by some intellectual process;—in short, by some form of self-suggestion.

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).