ON HALLUCINATION IN GENERAL.

Before proceeding, in the chapters which follow, to cite instances of hallucinations which purport to have been telepathically originated, it seems needful to glance briefly at sensory hallucination in general. To most persons, no doubt, the word connotes disease. Their ideas of hallucination are probably derived from vague reports of asylum experience and delirium tremens; or at least from the cases of Goethe's butt, Nicolai, the Berlin bookseller, and the Mrs. A. whose experiences are described in Brewster's Letters on Natural Magic, both of whom are known to have been under medical treatment for illness of which the hallucinations were regarded as a symptom. Indeed, until recent years the tendency of even well-instructed opinion has been to regard a sensory hallucination as necessarily implying some physical or mental disorder. This misconception—for it is a misconception—has had some curious consequences. Since it does occasionally happen that a person admittedly sane and healthy reports to have seen the likeness of a human figure in what was apparently empty space, such reports have been by some perforce scouted as unworthy of credence, and by others regarded as necessarily indicating some occult cause—as testifying, in short, to the agency of "ghosts." There was indeed the analogy of dreams to guide us. Few educated persons would regard dreams, on the one hand, as a symptom of ill-health, or on the other as counterparts or revelations of any super-terrestrial world; or, indeed, as anything else than purely subjective mental images. Yet dreams belong to the same order of mental phenomena as hallucinations, and are commonly so classed—such differences as exist being mainly due to the conditions under which the two sets of phenomena respectively occur. In fact, a hallucination is simply a hypertrophied thought—the last member of a series, whose intermediate terms are to be found in the mind's-eye pictures of ordinary life, in the vivid images which some artists can summon at will, and in the Faces in the Dark which many persons see before passing into sleep, with its more familiar and abundant imagery.

Of recent years, however, our knowledge of hallucinations has been largely augmented from two distinct sources. On the one hand, a systematic attempt has been made to study the spontaneous non-recurrent hallucinations occurring amongst normal persons; on the other hand, wider knowledge of hypnotism and the discovery of various processes for inducing hallucinations has afforded facilities for the experimental investigation of their nature, mechanism, and genesis, both in the trance and in waking life. The hallucinations, indeed, of the ordinary hypnotic subject, with which the public has been familiarised by platform demonstrations, are possibly not sensory at all. When a hypnotised lad eats tallow-candle for sponge-cake, drinks ink for champagne, or professes to see a lighted candle at the end of the operator's finger, we may conclude, if the performance is a genuine one, that a false belief has been engendered in his mind; but we have, in most cases, no evidence that this belief includes any sensory element. In many laboratory experiments, however, there can be little question that a complete sensory hallucination is induced, and that what the subject professes to see and hear is as real to him as the furniture or the person of the operator. One or two such cases have been quoted in a previous chapter (Chap. III., p. 68). The nature and reaction of these hypnotic hallucinations have been investigated with much ingenuity by various Continental observers.[93] MM. Binet and FÉrÉ, to quote the best-known series of experiments, have found, speaking generally, that the hallucinatory percept behaves under various conditions precisely as if it were a real percept. Thus, if the subject is told to see a picture on a blank card, he will not only see the picture at the time, but he will be able subsequently to pick out the card, recognising it by means of the hallucinatory picture impressed on it, from a number of similar cards. If the card is inverted, he will see the picture upside-down; if a magnifying glass is interposed, he will see the picture enlarged; viewed through a prism, it will appear doubled; it will be reflected in a mirror; and if the hallucinatory image consists of written or printed words, he will see the writing in the mirror inverted. Hallucinatory colours will develop after-images of the complementary colour, precisely as if coloured surfaces were actually present to the eyes of the hallucinÉ; and a mixture of these hallucinatory colours will produce the appropriate third colour. If other proof were needed of the sensory nature of the induced affection, MM. Binet and FÉrÉ find it in the observation that with cataleptic subjects who have lost the sensitiveness of the cornea and conjunctiva, this sensitiveness is restored when a visual hallucination is enjoined upon them. M. Pierre Janet, in L'Automatisme Psychologique, has recorded a similar restoration of sensitiveness in a subject's arm by the imposition of a tactile hallucination.

It is right to point out that these experiments, by the authors' admission, succeed only occasionally, and that many of them have not yet been confirmed by other observers. In fact, according to the evidence collected by the S.P.R., the results of applying such optical tests differ with each individual. Thus Mr. Myers succeeded by post-hypnotic suggestion in inducing two young men to see hallucinatory images in the crystal enlarged by the application of a magnifying glass (S.P.R., viii. 462, 463), and Miss X. (id., pp. 485, 486) reports that she sees hallucinatory pictures distorted in a spoon, reversed in a mirror, enlarged by a magnifying glass, and doubly refracted by Iceland spar. She believes herself also to have experienced complementary colours as the result of prolonged looking at a hallucinatory picture. But Mrs. Verrall (id., p. 474) finds the crystal pictures vanish when the magnifying glass is applied; and Miss A. (id., p. 500) finds that the superimposition of a magnifying glass does not affect the picture. In all these cases, it should be noted, the percipients were in their normal condition, and were more or less familiar with the nature of the optical effects following under similar circumstances with real percepts.

MM. Binet and FÉrÉ suppose that the appropriate reaction of the hallucinatory picture to the various tests described is due to the hallucination being built up round a fragment of actual percept, such as a mark on a card, which would conform to ordinary optical laws. This imaginary nucleus they name the point de repÈre. It is not improbable that in some cases this may be the true explanation. But experience leads us to infer that suggestion would be competent to produce all the observed effects in cases where the subject, either from previous knowledge of the instrument or process, from the behaviour of the investigators, or from his own observations at the time, was aware of the nature of the effect to be expected. And it is not clear that MM. Binet and FÉrÉ, and other investigators of this school, have been sufficiently on their guard against the abnormal receptivity of the hypnotised subjects with whom they have for the most part experimented. Miss X., it may be remarked, professes herself uncertain whether or not to ascribe the results which she has recorded to self-suggestion. But to choose between these alternative explanations is not important for our present purpose. To whatever cause we may attribute the results observed, there can be no doubt either of the sense of reality conveyed by the false percept, or of its appropriate behaviour under favourable conditions.

An instance may be quoted in detail which illustrates at once the apparent attachment of the hallucination to an external object, and its successful competition with the impressions of waking life. A lady of my acquaintance, Sister L., was put into the hypnotic state by Mr. G. A. Smith in the spring of 1892. Whilst she was entranced, Mr. Smith, at my request, handed to her several blank cards, and told her that one of them (which had been privately marked on the back) bore a portrait of himself, and that she was to look at it ten minutes after waking. A few minutes later, when engaged in conversation and apparently completely awake, Sister L. picked out the card in question from the little heap of similar cards and showed it to me, remarking that it was an excellent likeness. Some half-hour later, when Sister L. was about to take her departure, I handed her the card and said that Mr. Smith would be glad if she would accept the photograph. She looked at the card, expressed her thanks for the gift, and placed it in her pocket. When I met her a few days later I learnt that on her arrival at home she had searched in her pocket for the photograph, and had been much surprised to find there only a blank card. In this instance there can be little doubt that a complete sensory hallucination was induced, and that it persisted, or was capable of being revived, for some 30 minutes or more after the original impression had been established.

This last example, it will be seen, belongs to the important class of post-hypnotic hallucinations—i.e., hallucinations enjoined on the subject in the hypnotic state, but realised only after waking. Special interest attaches to hallucinations of this kind, because the subject is in a condition which, if not fully normal, at least approaches in some cases very nearly to the normal, and is thus able to observe and describe his own sensations with care.[94]

A more striking form of the same experiment, the post-hypnotic production of a completely developed hallucination of the human figure, has been practised by Bernheim,[95] Beaunis,[96] Liegeois,[97] and others. Thus M. Liegeois, on the 12th October 1885, told a hypnotised subject that on the 12th October of the year following he would go to Dr. LiÉbeault's house, where he would also see M. Liegeois, and would thank them both for the good done to his eyes. He would then see a performing dog and monkey enter the consulting room, where they would perform many amusing tricks; ultimately he would see a gipsy enter with a bear, to reclaim the dog and monkey, and would borrow two sous from M. Liegeois to give to the gipsy. On the 12th October 1886 the subject entered Dr. LiÉbeault's consulting room and thanked him and M. Liegeois as arranged. He then saw a dog and monkey enter the room, and ultimately a gipsy. The bear he did not see, and the two sous, which were duly borrowed, he handed to the imaginary dog. With these exceptions the hallucinations enjoined a year before were exactly realised. Some experiments of a similar nature are recorded by Mr. Gurney (Proc. S.P.R., vol. v. pp. 11-13). The subject was a servant named Zillah, in the service of Mrs. Ellis, of 40 Keppel Street, Russell Square. In the first two experiments Zillah was told in the trance that at a certain hour on the following day she would see Mr. G. A. Smith. In each case the experiment succeeded.

The third and last experiment with this "subject" was made on Wednesday evening, July 13th, 1887. On this occasion S. told her, when hypnotised, that the next afternoon at three o'clock she would see me come into the room to her. She was further told that I would keep my hat on, and would say, "Good afternoon;" that I would further remark, "It is very warm;" and would then turn round and walk out. These hallucinations were suggested in another room, where Zillah was taken for the purpose, and neither Mrs. Ellis nor any other person, except S. and myself, knew their nature. Zillah, as usual, knew nothing about them on waking. On the second day after, the following letter was received from Mrs. Ellis:—

"40 KEPPEL STREET, RUSSELL SQUARE, W.C.,
July 14th.

"DEAR MR. SMITH,—Mr. Gurney did not ask me to write in case there was anything to communicate with respect to Zillah, but as I suppose you gave her a post-hypnotic hallucination, probably you will wish to hear of it. I will give you the story in her own words, as I jotted them down immediately afterwards—saying nothing to her, of course, of my doing so. She said: 'I was in the kitchen washing up, and had just looked at the clock, and was startled to see how late it was—five minutes to three—when I heard footsteps coming down the stairs—rather a quick, light step—and I thought it was Mr. Sleep' (the dentist whose rooms are in the house), 'but as I turned round, with a dish mop in one hand and a plate in the other, I saw some one with a hat on, who had to stoop as he came down the last step, and there was Mr. Gurney! He was dressed just as I saw him last night, black coat and grey trousers, his hat on, and a roll of paper, like manuscript, in his hand, and he said, 'Oh, good afternoon.' And then he glanced all round the kitchen, and he glared at me with an awful look, as if he was going to murder me, and said, 'Warm afternoon, isn't it?' and then, 'Good afternoon' or 'Good day,' I'm not sure which, and turned and went up the stairs again, and after standing thunderstruck a minute, I ran to the foot of the stairs, and saw like a boot just disappearing on the top step.' She said, 'I think I must be going crazy. Why should I always see something at three o'clock each day after the sÉance? But I am not nearly so frightened as I was at seeing Mr. Smith.' She seemed particularly impressed by the 'awful look' Mr. Gurney gave her. I presume this was the hallucination you gave her.
"AMELIA A. ELLIS."

It is important to note that in cases of this kind there is no discoverable point de repÈre, at least in the sense in which the phrase is understood by its authors; and the nature of the effect produced—a moving figure, apparently occupying a position in solid space—makes it very difficult to suppose that the hallucination is attached to any external object, which must necessarily be fixed. But the whole discussion about the necessity of external excitation or of points de repÈre seems beside the mark in such cases as these. For there can be no question that what in the first instance excites the hallucination is not a present sensation, but a memory. Whether for the full development of a sensory hallucination some external stimulus to the sense-organ is necessary is here a question of quite minor importance. The really interesting fact in its bearing on the question of telepathic hallucination is that some hallucinations are shown to be centrally, not peripherally, initiated. It should be further remarked that Zillah's astonishment at seeing the figure is typical, since in the case of post-hypnotic hallucinations in general neither the injunction to see the figure, nor indeed any other incident of his trance life, is remembered by the percipient in the normal state; and he is therefore entirely ignorant of the chain of events which led up to the hallucination, and can only by inquiry and reflection ascertain that the apparition which he has seen is of his own manufacture.

From these experimental cases we may pass to the consideration of spontaneous hallucinations, and amongst them to that class with which we are more directly concerned, the occasional hallucinations of sane and healthy persons. Owing, amongst other causes, to their comparative infrequency, and to the difficulty of obtaining accurate contemporary records (since their occurrence cannot, as in the hallucinations of disease, be foreseen), phenomena of this class have hitherto attracted little attention amongst psychologists.[98] Mr. Edmund Gurney, however, in 1884 and onwards conducted an inquiry, by means of a printed schedule of questions, amongst a circle of some 6000 persons; and during the last four years, at the request of the Congress of Experimental Psychology which met at Paris in 1889, Professor Henry Sidgwick, with the aid of a Committee of members of the S.P.R., has carried on a similar investigation on a larger scale. 17,000 adult persons, for the most part resident in the United Kingdom, have been questioned as to their experience of sensory hallucinations.[99] In the result it appeared that 1684 out of 17,000, or 9.9 per cent.—to wit, 655 out of 8372 men, and 1029 out of 8628 women—had experienced a sensory hallucination at some time in their lives. In about one-third of the cases the percipient had more than one experience of the kind. The phenomenon, therefore, though not so common as dreaming, is less rare than is generally supposed, seeing that about one in every ten educated persons has such an experience in the course of his life. The inquiries of the Committee have revealed no general cause for the greater number of these isolated hallucinations. In a small proportion of the cases there was a slight degree of ill-health, and in a rather greater number there was a certain amount of anxiety or other emotional excitement, to which the hallucinatory experience might with some plausibility be attributed.[100] But in the great majority of the cases there was no obvious antecedent to be discovered either in the condition of the percipient or in the surrounding circumstances, and we are led to the conclusion that an isolated hallucination of this kind is as little incompatible with ordinary health as a blush or a hiccough. At the same time we are entitled to infer, from the relatively large proportion of cases occurring when the percipient is in bed, or alone, that quiescence and freedom from external stimuli are favourable conditions for the genesis of hallucinations.[101] They may, in short, be regarded as unusually vivid dreams, and have for the most part just so much interest and significance. The nature and variety of these casual hallucinations may be gathered from the table on the following page.

If we turn to the mechanism of hallucinations, we shall find that—like dreams—some are apparently originated by the condition of the bodily organs; others again appear to be mere automatic reverberations of recent sensation; whilst yet others cannot be referred to any immediate external stimulus, and suggest the "spontaneous" activity of the higher cerebral centres. With the rudimentary hallucinations—singing in the ears, sparks and flashes of light, etc.—which are caused by transient conditions of the external organs of sense, we are probably all familiar. But experience shows that a small nucleus of actual sensation may enter into more fully developed hallucinations. Thus, to take the simplest case, it is known that "sparks" may develop into "Faces in the Dark," which are themselves on the border-line between mind's-eye pictures and hallucinations. (See St. James's Gazette, "Faces in the Dark," Feb. 10, 1882, and Proc. S.P.R., vol. iii. p. 171.) And in another recorded case (Proc. S.P.R., vol. i. pp. 102, 103) an artist was accustomed to see constantly at his studio the figure of a man, under circumstances which strongly suggest that a point de repÈre was furnished by those floating motes in the eyeballs which are liable momentarily to cloud the vision when the position is abruptly changed after a period of immobility. And we find cases where the constructive impulse has so amplified and misinterpreted the data of normal sensation that we hardly know whether to class the result as hallucination or illusion. Thus, in a case given in Phantasms (vol. ii. p. 28), a young girl sees the face of a friend growing out of a yellow pansy; and an account of a similar incident has recently been furnished to me by Mr. H. Smith, of the Central Telegraph Office. The reference in the first line of the following narrative is to a rumour of the house being haunted, the remembrance of which possibly gave a definite form to the apparition:—

HALLUCINATIONS CLASSIFIED ACCORDING TO THE SENSE AFFECTED AND ACCORDING TO THE KIND OF PERCEPT.

Note

Table Continued