Some Points in the Physiology and Psychology of Hypnotism. - Authorities and their Theories. - Expectant Attention, Suggestion, and Inhibition. - Induction of Functional Aphasia, and what it teaches. - Exaggeration or Suppression of Certain Senses and Functions in the Hypnotic State. - Automatism in Hypnotism and in the Pathological State. - Amnesia. - Hypnotism compared with the Action of Poisons. - The Double Brain: its Single Action in Health and Possible Dual Action in Disease and in the Hypnotic State. - Cases illustrating this. - The Induction of Automatism without Hypnotism.

The study of hypnotism will doubtless do much to advance our knowledge of the higher brain functions, and it is well to bear in mind that, as the phenomena depend upon an induced psychical condition, they may not be explicable by any physiological method which we at present possess. McDougall * thinks that enlightenment will come from the psychological rather than the physiological side, and Wingfield strongly favours that view. Charcot, Richet, Bernheim, Heidenhain. Hack Tuke, Ferrier, Hughlings Jackson, and others, have, however, done most useful work by building up a working hypothesis, which serves as a standpoint for future investigators.

Expectant attention, suggestion, and inhibition are the processes which afford an explanation of the commonest phenomena.

Expectant attention seems to be a necessary psychical preparation, for an ordinary person may gaze at an object for an indefinite time without producing hypnosis, unless he expects such a result to ensue. Were this not so, spontaneous somnambulism would be of very common occurrence.

* 'Body and Mind,' p. 350. 132

Brown-Sequard and other neurologists show that when one cerebral centre or function is used to excess, the others become, for the time being, paralyzed or inhibited; and Dr. Maudsley says ('The Pathology of the Mind,' p. 58) that two nerve centres of mental function cannot be in equally conscious function at the same time. Continuous stimulation of one centre implies diminished activity of those surrounding it - including those of higher cerebration: volition, attention, co-ordination of ideas, and memory - and causes their temporary inhibition. This is seen in everyday life. When reading an interesting book, we greatly exert our intellectual and emotional faculties, and consequently impressions on other senses are not registered or noticed. A noise in the street is unheard by us; a coal may fall on the hearthrug, and we neither see the accident nor are affected by the smell of burning wool; even bodily pain and mental suffering may be forgotten or benumbed while the attention is thus absorbed.

Everyone knows how gentle friction of a skin surface, in neuralgia or headache, will often act in the same way, by over stimulating one sensory centre, and rendering inactive that which registers the pain.

Heidenhain attributes the hypnotic state to monotonous gentle stimulation of a sense, causing inhibition of the cortical cells, with consequent suspension of the higher cerebral functions. A monotonous sound or scene will thus induce drowsiness or sleep, and a sudden intense stimulation, such as a sudden noise or flash of light, will cause an awakening. This is seen at magnetic seances, where the sleepers are commonly aroused by the sound of a gong.

Let us consider what happens when a person is profoundly hypnotized for the first time by fixation of the eyes upon a brilliant object. As his attention is exclusively directed to one sensory impression, he becomes more and more withdrawn from other conditions of the environment, until at last he sees only the object, and is conscious of nothing else. But in time, as the optic centres become exhausted and cease to respond to continued stimulation, the visual sense likewise becomes extinct, and the subject is left in a condition of mental vacuity and ' senselessness.' He has been reduced from a state of polyideism, which is the normal condition of the healthy man, who is constantly receiving and balancing multiform impressions derived from all the avenues of sense, first, to a state of mono-ideism - the idea of a fixed image, upon which he must keep his eyes and attention; and, finally, to a state of vacuity, in which there is complete absence of ideas. Into this swept and garnished chamber of the mind ideas can be implanted by the hypnotist; and, as a ray of light thrown into a darkened room will show forth with exaggerated force and brilliancy from the contrast with the surrounding darkness and the exclusion of conflicting rays, so will the idea suggested to the imagination of the profoundly hypnotized subject operate with immensely increased effect from the absence of conflicting and corrective impressions derived from the whole environment.

As the patient, on recovering consciousness, in some cases may continue the speech or occupation which was interrupted by an injury to the brain, so the hypnotized person, on being aroused, will sometimes carry on a phrase or an action from the point at which it was broken off by hypnotic influence - thus showing how completely the brain, as the organ of mind, has been paralyzed. But whereas in the coma of disease the paralysis is absolute and complete, in induced somnambulism it is partially or entirely removable at the command of the operator. He can arouse any centre to more than its normal functioning activity, so that the subject, who a moment before was insensible to the fumes of strong ammonia held close to his nostrils, will now recognize the faintest odour; and he who now lies in a condition of muscular impotence will, at the word of the operator, perform extraordinary feats of strength. The same holds good with the expression of the emotions. From a state of abject misery, the subject may be suddenly transported to one of bliss, and be it noted that he shows both conditions far more markedly than he would do if awake: for in the normal state our emotions are subject to that inhibitory influence which we call self-control, and which is non-existent in the somnambulic subject, over whom each passion, each emotion that is called up, has for the moment an undivided sway.