Before leaving this subject of spontaneous sleep-waking states I ought briefly to mention a form of trance with which we shall have to deal more at length in a later chapter. I speak of trance ascribed to spirit-possession. As will be seen, I myself fully adopt this explanation in a small number of the cases where it is put forward. Yet I do not think that spirit-agency is necessarily present in all the trances even of a true subject of possession. With all the leading sensitives—with D. D. Home, with Stainton Moses, with Mrs. Piper and with others—I think that the depth of the trance has varied greatly on different occasions, and that sometimes the subliminal self of the sensitive is vaguely simulating, probably in an unconscious dream-like way, an external intelligence. This hypothesis suggested itself to several observers in the case especially of D. D. Home, with whom the moments of strong characterisation of a departed personality, though far from rare, were yet scattered among tracts of dreamy improvisation which suggested only the utterance of Home's subliminal self. However we choose to interpret these trances, they should be mentioned in comparison with all the other sleep-waking states. They probably form the best transition between those shallow somnambulisms, on the one hand, which are little more than a vivid dream, and those profound trances, on the other hand, in which the native spirit quits, as nearly as may be, the sensitive's organism, and is for the time replaced, as nearly as may be, by an invading spirit from that unseen world.
This brief review of non-hypnotic somnambulisms has not been without its lessons. It has shown us that the supernormal powers which we have traced in each of the preceding chapters in turn do also show themselves, in much the same fashion, in spontaneous sleep-waking states of various types. We must now inquire how far they occur in sleep-waking states experimentally induced.
And here the very fact of induction suggests to us a question specially applicable to the hypnotic state itself. Is hypnosis ever supernormally induced? Can any one, that is to say, be thrown into hypnotic trance by a telepathic impact? or, to phrase it more generally, by any influence, inexplicable by existing science, which may pass from man to man?
In the first place one may say that of the anti-mesmeric schools of opinion, the "purely physiological" school has on the whole failed, the "purely suggestive" school has triumphantly succeeded. The school of Nancy, reinforced by hypnotists all over Europe, has abundantly proved that "pure suggestion" (whatever that be) is the determining cause of a very large proportion of hypnotic phenomena. That is beyond dispute; and the two other schools, the "pure physiologists" and the "mesmerists" alike, must now manage to prove as best they can that their favourite methods play any real part in the induction of any case of hypnosis. For to the pure suggestionist, monotonous stimulation and mesmeric passes are alike in themselves inert, are alike mere facilitations of suggestion, acting not directly on the patient's organism, but rather on his state of mental expectation.
I reply that there is absolutely no need to go as far as this. In admitting suggestion as a vera causa of hypnosis, we are recognising a cause which, if we really try to grasp it, resolves itself into subliminal operation, brought about we know not how. So far, therefore, from negativing and excluding any obscure and perhaps supernormal agency, the suggestion theory leaves the way for any such agency broadly open. Some unknown cause or other must determine whether each suggestion is to "take" or no; and that unknown cause must presumably act somehow upon the subliminal self. We should have something like a real explanation of suggestion, if we could show that a suggestion's success or failure was linked with some telepathic impact from the suggester's mind, or with some mesmeric effluence from his person.
I know well that in many cases we can establish no link of this kind. In Bernheim's rapid hospital practice there seems no opportunity to bring the hypnotist's will, or the hypnotiser's organism, into any effective rapport with the subject. Rather, the subject seems to do all that is wanted for himself almost instantaneously. He often falls into the suggested slumber almost before the word "Dormez!" has left the physician's mouth. But on the other hand, this is by no means the only type of hypnotic success. Just as in the mesmeric days, so also now there are continual instances where much more than the mere command has been needed for effective hypnotisation. Persistence, proximity, passes—all these prove needful still in the practice even of physicians who place no faith at all in the old mesmeric theory.
The fact is, that since the days of those old controversies between mesmerists proper and hypnotists proper, the conditions of the controversy have greatly changed. The supposed mesmeric effluence was then treated as an entirely isolated, yet an entirely physiological phenomenon. There was supposed to be a kind of radiation or infection passing from one nervous system to another. It was of this that Cuvier (for instance) was convinced; it was this theory which Elliotson defended in the Zoist with a wealth of illustration and argument to which little justice has even yet been done. Yet it was hard to prove effluence as opposed to suggestion, because where there was proximity enough for effluence to be effective there was also proximity enough for suggestion to be possible. Only in some few circumstances,—such as Esdaile's mesmerisation of a blind man over a wall,[93]—was it possible to claim that the mesmeric trance had been induced without any suspicion whatever on the subject's part that the mesmerist was trying to entrance him.
Since those days, however, the evidence for telepathy—for psychical influence from a distance—has grown to goodly proportions. A new form of experiment has been found possible, from which the influence of suggestion can be entirely excluded. It has now, as I shall presently try to show, been actually proved that the hypnotic trance can be induced from a distance so great, and with precautions so complete, that telepathy or some similar supernormal influence is the only efficient cause which can be conceived.
I subjoin one of a series of experiments in this "telepathic hypnotism." (See Appendix V. C.) These experiments are not easy to manage, since it is essential at once to prevent the subject from suspecting that the experiment is being tried, and also to provide for his safety in the event of its success. In Dr. Gibert's experiment, for instance, it was a responsible matter to bring this elderly woman in her dream-like state through the streets of Havre. It was needful to provide her with an unnoticed escort; and, in fact, several persons had to devote themselves for some hours to a single experiment.
I have cited first this experiment at a distance, without attempting to analyse the nature of the suggestion given or power employed by the hypnotist. Of course it is plain that if one can thus influence unexpectant persons from a distance there must be sometimes some kind of power actually exercised by the hypnotiser;—something beyond the mere tact and impressiveness of address, which is all that Bernheim and his followers admit or claim. Evidence of this has been afforded by the occasional production of organic and other effects in hypnotised subjects by the unuttered will of the operator when near them. The ingenious experiments of Gurney[94] in the production of local rigidity and anæsthesia were undertaken to test whether the agency employed were more in the nature of an effort of will or,—as the early mesmerists claimed,—of an emission of actual "mesmeric fluid" or physical effluence of some sort. Gurney was inclined to think that his results could not be explained solely by mental suggestion or telepathy, because the physical proximity of the operator's hand seemed necessary to produce them, and he thought it probable that they were due to a direct nervous influence, exercised through the hand of the operator, but not perceptible through the ordinary sensory channels. Mrs. Sidgwick's experiments[95] of the same kind, however, in which success was obtained when the operator was standing with folded arms several feet away from the subject, removed Gurney's main objection to the telepathic explanation. The fact that a thick sheet of glass over the subject's hands did not interfere with the results also afforded some presumption against the hypothesis of a physical influence; and Mrs. Sidgwick pointed out that the delicate discrimination involved in the specific limitations of the effects is much more easily attributable to mental suggestion, through the action of the operator's mind on that of the subject, than to any direct physical influence on the latter's nerves.