Popular Science Monthly/Volume 49/July 1896/Suggestion in Therapeutics
|SUGGESTION IN THERAPEUTICS.|
By Prof. WILLIAM ROMAINE NEWBOLD.
IF there be any truth in the doctrines I have already put forth in these pages, it seems a priori probable that suggestion will prove useful in combating some of the many ills that flesh is heir to. The various devices for heightening suggestibility are simply devices for increasing the effects proper to any given mental state by removing from its path all obstacles. Among the effects of mental states are the production and prevention of other states and of movements, and there are many diseases which are characterized by disturbances of sensation, thought, or movement. Very often these disturbances are functional—that is, they can not be traced to any visible injury of the nervous system, and frequently appear and disappear in most unaccountable fashion. It does not seem improbable that in such cases suggestion might work effects worthy of serious consideration.
And in fact it does. Every physician knows that it does, even though he has never heard the word "suggestion," or laughs at the theories of Nancy. Instinctively every trained practitioner supports his remedies by suggestion, cheering the patient by word and look, pooh-poohing his fears, assuring him of a speedy recovery, and often, if he be somewhat wiser than common, expatiating upon the specific results expected from the dose now to be administered.
The movement known as Psychotherapeutics or Suggestive Therapeutics is an attempt to dissociate this element of medical practice from its concomitants in order to determine its value when taken by itself. What that value is I shall not venture to say. In all probability the advocates of the method—or some of them—exaggerate its efficacy, and doubtless the personality of the physician has much to do with its success. In one man's hands suggestion will work wonders; in those of another it is almost valueless. Yet the evidence is rapidly accumulating, and every year sees a greater consensus among those who have made the trial as to the limits within which it is of value.
I can not undertake in one short article to go into the details of the results reported by von Krafft-Ebing, von Schrenck-Notzing, Forel, Ladame, Moll, Wetterstrand, van Renterghem and van Eeden, Liébeault, Bernheim, Janet, Bérillon, Pitres, de Jong, Bramwell, Lloyd Tuckey, Hamilton Osgood, and others, but I can say a few words as to the troubles in relieving which suggestion has been found useful.
In the first place, it will sometimes overcome insomnia. In the second, it has been used to restore to hysterical patients their lost sensations, but the restoration is usually but temporary. In the third, it may be used to destroy all sorts of disagreeable symptoms, especially neuralgic pains and headaches. It is possible to produce complete anæsthesia for surgical purposes in this way; but, as ether, chloroform, and cocaine are much more reliable, suggestion is seldom used. Dr. Wetterstrand, however, usually hypnotizes slightly before administering an anæsthetic; he has found that he can in this way get along with a much smaller amount of the drug, and also avoid the "violent" stage.
In the fourth place, suggestion is sometimes efficacious in cases of disordered ideation and morbid impulses. Mild melancholia, horror of food and of open spaces, insane doubt, homicidal and suicidal impulses, sexual perversion and inversion, dipsomania, morphinomania, fear of death, and others of the kind have been successfully treated by suggestion. But upon the more serious forms of mental disease it seldom has any effect.
In the fifth place, it is often of aid in motor disorders not dependent upon organic disease of the nervous system. Such are hysterical contractures, paralyses and convulsions, nervousness, chorea, sudden loss of voice, stammering, twitching of muscles, etc.
These are the troubles in which suggestion has been found most useful, but of course no one claims that it is a specific for them all. It often does good and never does harm; but sometimes it does no good, and at other times the improvement is but temporary. There is nothing very surprising in the fact that such troubles have sometimes been found amenable to suggestion. Although the effect ascribed to the mental state may be greater than we usually suppose such a state could produce, the difference is one of degree and not of kind. But I must now turn to a group of phenomena which seem at first glance to differ in kind as well as degree from anything with which we are familiar.
We usually conceive that the processes grouped under the word metabolism depend upon purely mechanical and chemical conditions, modified in some way, to be sure, by the fact that the body is alive and not dead, but still essentially physical and chemical. The word metabolism comes from a Greek word (μετα-βολή) which means "exchange," and it designates the fact that we suppose all the processes of nutrition and decay, secretion, assimilation, excretion, oxidation, etc., to be at bottom alike, and in the last analysis to consist in an exchange or substitution of atom for atom within the constituent molecules of the body.
Now, it is easily shown that this notion is erroneous, for the physical and chemical processes taking place within the body are not precisely like other such processes; they stand to some extent under the control of the nervous system. For example, the amount of heat evolved within the body is probably regulated by a center in the spinal cord. The nutrition of the voluntary muscles probably depends upon the functioning of certain cells in the anterior horns of the spinal cord, and if the latter are destroyed the muscles waste away. Dr. Darkschwitsch has recently published in the Archiv für Psychiatrie an elaborate study of certain forms of muscular atrophy complicated with painful disease of the joints. These frequently follow paralyses due to injury of the cortex, and he concludes that the metabolic changes probably result directly from the cortical injury and not from disuse of the affected limbs. I recollect seeing some time ago a patient of Dr. Charles K. Mills's who had had the left cortical center for the hand removed to cure an epilepsy. He had lost in consequence, as was to be expected, much of his power over the right arm and hand, and he had also lost, as was not to be expected, all the skin of his right hand. Dr. Mills told me he had several times seen localized metabolic disturbances follow lesion of that region of the cortex which controlled the muscles of the affected part.
Besides this probable direct control, the nervous system can affect metabolic processes indirectly through the blood supply. The distribution of the blood is regulated by the complex vasomotor mechanism which controls the force and rate of the heartbeat and the diameter of the arteries and arterioles; the entire system is controlled in turn by a center in the medulla. It acts for the most part reflexly, sending the blood tide with the greatest force to the organ that needs it most, but it can be affected in other ways.
Such facts are interesting, and they put it beyond question that the nervous system has to do with the processes of metabolism, but they do not show how those processes can be affected by the functioning of that part of the nervous system which underlies consciousness, or, to use my former phraseology, how mental states can control metabolism.
That some metabolic processes can be affected by mental states is well known. For example, the secretory and excretory processes can not only often be started and stopped in this way, but the chemical character of their products can be modified, as when a sudden fit of anger makes a mother's milk poisonous to her child.
In general, an emotional storm or even an emotional mood, if long continued, may have a profound effect upon the functioning of the body. The cheerful emotions favor health; the depressing emotions make the body fertile ground for the growth of disease germs. Yet even this admission does not bring one much nearer the point of interest; for, since the epoch-making discoveries of Prof. James, of Harvard, and Prof. Lange, of Copenhagen, it has been known that what we call an emotion is not the cause but the feeling of those extensive bodily changes which we regard as its expression, and to inquire into the effect of emotions upon metabolism would lead me too far afield into the general theory of emotion.
To account for the more remarkable effects of suggestion upon metabolism we are forced to a most extraordinary hypothesis, which may be thus stated:
The thought of any given bodily change, whether motor, vasomotor, or metabolic, tends to the actual production in the body of the change which that thought represents.
That this law is true of motor thoughts I think quite clearly proved. Of the vasomotor it is not so clearly true, but there is a considerable amount of evidence going to show that the blood tide can be to some extent directed by act of will by most persons, and by some persons to a much greater extent. The evidence for any control over the metabolic processes is very scanty. If the tendency exists, it must be latent in most persons, for we all know that I can not by thinking add a cubit to my stature or change the color of my beard. Yet, even though it be latent in most persons, it may exist in others, and I think the evidence for its existence is strong. The chief difficulty in accepting it lies in this: we know of no nervous mechanism by which such central processes can affect the body unless it be through the sensory nerves, and, according to our present physiology, sensory nerves can carry impulses in one direction only.
I can not explain these difficulties and shall not attempt to. I shall simply relate the more important bits of evidence which have been gathered since the 12th of May, 1885, when M. Focachon performed his first successful experiment under satisfactory conditions before the professors of the Medical School at Nancy. Most of this evidence is experimental and it deals with modifications of the skin only. I do not suppose that this fact proves that the control of thought over the skin is greater than that which it exercises over the internal organs, but merely that experiments upon the skin are more satisfactory than those on other parts of the body, partly because their results are more manifest and partly because they are attended with less discomfort to the patient. They belong to two types: (1) those in which the modifications induced are chiefly vasomotor—redness, swelling, exudation of blood, etc.—but greater than one can usually produce by an act of will; and (2) those in which there is visible change in the tissue. It is quite possible that the latter are due in large part to vasomotor modifications, but we can not at present prove that such is the case. In connection with these experimental cases I shall introduce a few parallels derived from other sources to show their absolute identity of type.
The first case which I shall quote is reported by Dr. Biggs, of Lima, and is recorded by Mr. F. W. H. Myers in the Proceedings of the Society for Psychical Research, vol. vii, page 339. In three cases Dr. Biggs produced a red cross upon the skin by suggestion. His own account of the first of these cases, slightly abbreviated, is given as follows in a letter dated October 18, 1885:
"I put her into a magnetic or mesmeric sleep by laying my hand on her head for about a minute. I then said, 'Maria, do you hear me?' 'Yes.' 'Are you thoroughly magnetized?' 'Yes.' 'Now listen attentively: a cross is going to appear on your right forearm and remain there until I tell it to go away. Here is where it is to appear.'(I then described a cross with my forefinger on the inner side of her right forearm.)' Have you understood what I have said to you?' 'Yes.' I then awakened her by two or three up-passes; for the next two or three days she seemed sulky and out of sorts, would now and then rub her right arm, over the place where the cross was to appear; when asked why she did this, she said there was an itching and she could not help scratching the place, although there was nothing to be seen that could cause the irritation. I then magnetized her as before, and asked, 'Do you recollect what I told you the other day about the cross that is to appear upon your arm?' 'Yes.' 'Will it appear?' 'Yes.' 'When?' 'In a few days.' 'Well, it must come out in three days; do you understand?' 'Yes.' By the time appointed a dusky red cross, four or five inches long and about three inches wide, made its appearance. At first we pretended not to notice this, although we could often see the lower part of it when her sleeve was partly rolled up in some of her duties in and about the house; she was our housemaid. It was only at intervals, when thrown into the magnetic sleep, that we could get a full view of the cross; never a word had been said to her about the cross in her waking moments, for some time, several weeks, until one day I pretended to have caught sight of the strange mark on her arm, and said: 'Why, Maria, what is the matter with your arm? Have you hurt it? What mark is this? Let me see; pull up your sleeve.' She did so with a slightly sulky, ashamed air. 'Why, it looks like a cross; where did you get this?' 'I don't know, sir.' 'How long has this been on your arm?' 'More than a month, sir.' 'Have you felt anything?' 'No, sir; only at one time I had a great deal of itching and burning, and a few days afterward this mark came out on my arm.' After this we frequently spoke to Maria about the cross, and when requested to she would roll up her sleeve and show it to visitors, although she always seemed reluctant to do so. Many months afterward she left our service, and in about two weeks she made her appearance at my office in town, asking me to remove the cross from her arm, as it attracted the notice of the family with whom she was now living, and she was much annoyed by the many questions asked her. I magnetized her, and then told her that the cross would disappear in a few days, and she would be no more troubled with it. I saw her a few days afterward at Salto; the cross had disappeared."
In another case Dr. Biggs caused a cross to appear every Friday on the chest for a period of nearly six months. These cases are not sufficiently well authenticated to make them of much value taken by themselves, but, in conjunction with the results got by other experimenters, they are worthy of consideration.
For example, Prof. Pierre Janet suggested to his hysterical patient Rose that he would put a mustard plaster upon her abdomen to relieve hysterical contractures of the stomach. "I found, some hours later," he says, "a swollen mark, dark red in color, in the form of an elongated rectangle, but—odd detail—none of its angles were clearly marked, for they seemed neatly cut off. I remarked that the burn had an odd shape. 'Don't you know,' said she, 'that the corners of the Rigollot plasters are always cut off so that they won't hurt?' "Following up this hint. Prof. Janet suggested putting on a plaster shaped like a six-pointed star, and he got the corresponding burn. On the chest of another patient he produced an S in the same way. Prof, von Krafft-Ebing has done the same with his famous patient Ilma Szandor.
Prof. Charcot's case of suggested œdema is even more curious, as it involved not merely vasomotor changes, but also a fall of temperature, and probably modified nutrition as well. It is reported by Dr. Levaillain. M. Charcot had presented two cases of hysterical blue œdema occupying the entire extremity of the upper limb and making the hands appear swollen, bluish, cold, contrasting in the highest degree in volume, temperature, and coloring with the hand of the opposite side. He then exhibited. in the auditorium a patient suffering from major hysteria who was hypnotizable. The following suggestions had been given her during the hypnotic sleep for four or five days: She was told her right hand was puffing out, becoming larger than the other; that it was getting blue, becoming red, then violet; finally, that it was hard and was getting colder and colder. Under the influence of these suggestions, repeated at five or six hypnotic sittings, the right hand became enormous very rapidly, almost double the volume of the other; it was really much discolored and of a true cyanic tint; it was hard to the touch, and the finger would not sink into it; finally, its temperature was three degrees (centigrade) below the normal temperature of the rest of the body. In a word, it resembled in every respect the hand of another hysteric who was suffering from a spontaneous blue œdema. It was, then, possible to produce and localize in the hand by means of simple suggestions lasting disorders of nutrition and circulation of such a character that the hand became half again as large, more colored, and much colder than the other hand."
Another curious vasomotor phenomenon is the "bloody sweat." It is sometimes found occurring spontaneously without visible reference to mental states. Such a case is reported by Dr. Ernoul, of St. Malo. A hysterical girl whom he observed had bleeding spots on various parts of her body which appeared and disappeared in most unaccountable fashion. A somewhat similar case was observed by Drs. Artigalas and Rédmond, in which the bleeding could be produced by suggestion. The patient was a young married woman, twenty-two years of age. She entered the hospital October 31, 1891, for various troubles requiring surgical treatment. Later she complained of pain in the ears, and had several hæmorrhages from them. On the 23d of November and the seven subsequent days she at times wept bloody tears. She called the doctors' attention to this on the 27th; they could find no injury in the eye, but learned that she had had in childhood frequent hæmorrhages from the nose and one from the stomach. A careful examination showed many hysterical symptoms. She was hypnotized, but it was not possible to check the bloody tears by direct suggestion; they could, however, be occasioned by suggestion at any time. "On December 1st, Prof. Artigalas put her again to sleep, and suggested to her that the hæmorrhages from the eye would not recur, but that she would bleed from the hollow of the left hand. A few minutes after being awakened she in fact had a hæmorrhage, or rather a bloody sweat, on the palm of the left hand. The phenomenon took place under our eyes without M. Artigalas leaving the patient and without any possibility of fraud. The skin was absolutely sound on the surface at the point which bled; the blood seemed to exude in the creases much as a profuse sweat would have done; one could not detect upon trial any appreciable modification of the integument. The hæmorrhage ceased upon washing the hand in cold water." The palmar hæmorrhages were then checked by suggestion.
Drs. Bourru, Burot, and Mabille have got even more curious phenomena in the case of their famous hysterical patient, Louis V——. They produced bleeding by suggestion from the nose, from designated points on the skin, and even fixed beforehand the hours at which the bleeding was to take place. On one occasion they heard him give himself, while in a secondary state, similar suggestions, and the blood appeared punctually on the spot indicated. Nothing could better demonstrate the subjective character of the agency that produces these inexplicable results.
These cases are precisely parallel to those of the so-called "stigmatics"—"saints" who bore upon their persons the marks of crucifixion. The hagiology of the Roman Catholic Church is full of them, and not a few have been observed in recent years. I will quote the case of one: Marie de Moerl, of Kaldern, in the Tyrol, became subject to ecstasy in 1832, she being then about twenty years of age. Generally the subject of her meditation was the passion of Jesus. "In the autumn of the same year her confessor perceived that the palms of her hands, where subsequently the marks of the crucifixion appeared, sank in, as if under the pressure of a body in half relief. At the same time the part became painful and frequently cramped. On the 2d of February, 1834, at the Feast of the Purification, he observed her wipe the middle of her hands with a towel and exhibit a childlike alarm at the blood which she perceived there. These marks soon showed themselves on her feet and her heart. They were nearly round, spreading a little in length, three or four lines in diameter, and seeming to pass through both hands and both feet. On Thursday night and Friday all these wounds shed drops of blood, ordinarily clear. On other evenings they were covered with a crust of dried blood."
The well-known case of Louise Lateau was precisely similar. At the present time, according to newspaper accounts, a certain Mrs. Stuckenborg, of Louisville, Ky., presents the phenomena of stigmatization. Dr. Hodgson told me he went to Louisville and endeavored to study the case, but found she was in the hands of the Roman Catholic authorities, and he was not allowed to examine her.
The ease with which warts can be "charmed away" by suggestion has long been known. I will quote two cases. The patient in the first case was my wife, then a little girl, and the account was written for me by her mother. "I remember it all perfectly. It was when E—— was about six years old, just before we went to Boston to live. She had had warts on her hands for over a year. They had spread until her hand was not only badly disfigured, but very painful, as they were apt to crack and bleed. Two physicians, both relatives of ours, had prescribed for them, and we had followed directions without success. We were in Lawrence, at M. P——'s. A lady came to tea, noticed the warts, and offered to remove them by a 'charm.' As I had once or twice been relieved in childhood in the same way, I was delighted at the offer. She went through some mummery, rubbing them and muttering something, I think, and then announced that they would be gone in a month. They were, every one. In a few days they began to dry up and disappear. So far as I can remember, she never had another. When I was a child there was a neighbor of ours who used to remove all the warts in the neighborhood. I never heard of his failing, and I know of many successful removals in our own family. He used a piece of thread. He would tie it around the wart—if he could—with great solemnity, rub it three times, and very carefully put the piece of thread in a paper in his pocketbook. This made a very great impression on us, I remember. It seemed next to a church service, having your wart taken off."
Dr. Bonjean, of Lausanne, in a letter to the Revue de l'Hypnotisme, dated March 3, 1896, tells an interesting story of the same sort. An old lady, a relative of his, had long had the reputation of being able to remove warts, and he had himself been cured by her of a very bad one. Her method was to bandage the eyes of the patient and instruct him not to touch the wart or disturb the bandage while she was operating. Her daughter then entered and touched the wart with an object (described by Dr. Bonjean) which could not have had any curative power. The warts disappeared in from one to three weeks. When the old lady died. Dr. Bonjean learned her secret. He saw clearly that her success must be due to suggestion, and he undertook to cure warts without the use of the object upon which she relied, but imitating her methods in other respects. He never hypnotizes the patient, and says he thinks it is only important to impress him deeply with the notion that the warts will go away.
Among the most extraordinary and best authenticated cases of suggested modification of the metabolic processes are those in which burns have been so produced. The first of these was, I believe, produced by M. Focachon, an apothecary of Charmes, in
France, on a patient named Elisa F—— He succeeded in doing it several times, and the details can be found in Prof. Beaunis's Le Somnambulisme provoqué, pages 72-84. I will describe one or two. On the 12th of May, 1885, at 11 a. m., she was hypnotized, and eight postage stamps were placed on her left shoulder, with the suggestion that a blister was being applied. She was then watched and kept asleep. At 8.15 a. m. next day, she was examined in the presence of MM. Bernheim, Liégeois, Liébeault, Beaunis, and others, and the bandages were removed. All were satisfied that they had not been disturbed. "Within an area of about four by five centimetres the epidermis was found thickened and deadened, of a yellowish color, but it was not raised and had not formed blisters. It was thickened, a little wrinkled, and in a word presented the appearance of the period which immediately precedes true blistering, with the formation of fluid. This region was surrounded by a zone of intense redness, with swelling about half a centimetre in extent." A year later M. Focachon succeeded in neutralizing the effect of a Spanish fly blister on the same patient. One piece was put on the left forearm and the other on the corresponding region of the other arm. She was hypnotized and told that the one on the left arm would not burn her. She was then watched nine hours and a half and examined. The left arm was almost absolutely unaffected; on the right a blister was forming. The bandages were replaced for forty-five minutes and then examined again. On the right arm was a blister from which a serous fluid was got; the left was intact.
Another such case was reported by Dr. J. Rybalkin, of the Hôpital Marie in St. Petersburg. The patient, a house painter, sixteen years of age, was hypnotized at 8.30 a. m., and was told he would burn himself on the arm by touching a stove—in which, by the way, there was no fire. He uttered a cry of pain when he touched it, and within a few minutes a red, painful mark appeared on the arm. The physicians then watched this develop into a complete burn. By 10 a. m. next day blisters had developed, these formed a scab, and the wound healed as an ordinary burn would have done.
With such extensive control of the metabolic processes of the skin experimentally demonstrated, it is not surprising to meet with remarkable cures of skin diseases. Thus Dr. Hamilton Osgood, of Boston, reports four cases of eczema and one of dermatitis cured or improved by suggestion. One, for example, was that of a boy of eleven, who had suffered from eczema since he was eighteen months old; his body was nearly covered by the eruption and consequent scabs, and the itching was intolerable. He had been treated by many dermatologists without the least success. Dr. Osgood hypnotized him and told him the itching would cease and the skin would become sound. The itching was immediately relieved, and the eruption was nearly gone in a fortnight and quite gone in a month.
The most extraordinary case of the kind, however, that I have yet seen comes from Moscow, and is vouched for by Prof. Kozhevnikoff, the most eminent neurologist of Russia. The account which I transcribe is from the British Medical Journal, November 16, 1895.
"A 'miraculous' cure has recently occurred in Moscow, where it has caused considerable excitement. It is perhaps a more than usually interesting instance, and therefore deserving of the permanent record given to it by Prof. Kozhevnikoff, who gave the details of the case at the last meeting of the Society of Neuropathologists in Moscow. The professor had not had the patient under his treatment, but had seen him more than once both before and after the 'cure.' The patient, N—— D——, was a lecturer in the Moscow University. He had suffered from a severe form of sycosis menti since June, 1894, for which he underwent treatment at the hands of various specialists—among others, of Profs. Kaposi, of Vienna; Schwimmer, of Buda-Pesth; Lassar, of Berlin; Pospiélof, of Moscow; and Stukovenkof, of Kief. In April last he returned to Moscow. His chin was then covered with a freely suppurating eruption. He now sought the advice of a 'wise woman,' an attendant at the baths, who was in the habit of giving herbs and 'simples' to her clients. In this case no such remedy was employed. N—— D—— was told to meet the woman next morning
at five o'clock in the Temple of the Saviour, the colossal church on the Moskva River, which has been building all the century and is yet incomplete, in memory of the famous events of 1812. He came as told, and while he remained a passive onlooker, the woman prayed for three or four minutes; the same thing was repeated that evening and again the following morning. But in the meantime the eruption of N—— D——'s face had begun to improve; the discharge ceased, the swelling subsided, and in twenty-four hours scarcely a sign of disease was left. Such are the facts as given by the patient himself, and confirmed by Prof. Kozhevnikoff. The professor, however, adds some important points bearing upon the case: The patient is of neurotic temperament; his sister is highly hysterical; he had frequently had boils on both arms with a marked tendency to symmetry in position; and the sycosis itself showed some signs of being, if not of nervous origin, at least under nervous influence. The impressive surroundings under which the 'cure' was wrought, and the mysterious cabalistic prayer—which the woman refused to divulge, lest it should begin to act with the person to whom she told it and cease to act with herself—are also factors to be remembered in connection with the neurotic-and impressionable character of the patient."
I might extend this catalogue almost indefinitely, but my space is limited. What shall we say of these facts? It is evident that they can not be explained by our present psycho-physiological theories, and many other attempts at explanation have been offered. The Roman Catholic ascribes them to the supernatural intervention of the Virgin or saints; the evangelical Christian sees in them the power of God, and an attempt has been made in recent years by the "faith healers" to make them an essential part of an evangelical creed in which "faith" is the divinely ordained instrument, not merely for the purification of the soul from sin, but for the deliverance of the body from disease as well. The self-styled "Christian scientists" and "metaphysical healers" approach the question from a pseudo-idealistic point of view. Mind, say they, is the only reality; things are nothing but very stable thoughts; the body exists only because the soul thinks it; disease is therefore merely a pernicious fixed idea: abolish the idea, and the disease is ipso facto abolished.
It is impossible for any one who has been trained in the study of natural phenomena to revert to such crude theories as these. The "scientific" man, to whom nothing is intelligible unless it is capable of interpretation in the mechanical conceptions of our latter-day atomism, usually finds it simpler to deny all facts which he cannot at once bring under those conceptions. He forgets that experience is the only test of truth, that our scientific conceptions are merely the tools which the human mind has devised in order to grapple with the infinite manifold of experience. They are good tools. They are as much better than the animistic conceptions of primitive man as our modern machinery is better than his axes and chisels of stone; yet our mental as well as our material tools can be improved. There are, I believe, engineering feats which our present appliances can not accomplish, and there are also, I believe, phenomena of Nature which our present conceptions are insufficient to explain. Yet I would not pronounce the former impossible or the latter essentially unintelligible.
- Carpenter, Mental Physiology, § 566.
- L'Automatisme Psychologique, p. 166.
- Eine experimentelle Studie auf dem Gebiet des Hypnotismus. Stuttgart, 1889. English translation by C. G. Chaddock, M. D., New York, 1889.
- Revue de l'Hypmotisme, vol. iv, p. 354, June, 1890. Cf, also Mr. Myers, op. cit., p. 337.
- Revue de l'Hypnotisme, iv, 283.
- Op. cit., vi, 250.
- Brierre de Boismont, Hallucinations, Case 100. English translation, Philadelphia, 1853.
- Liégeois, De la Suggestion, § 278.
- Cf. Revue de l'Hypnotisme, iv, 361, and Myers, op. cit., 338.
- Revue de l'Hypnotisme, ix, 300.
- See a more complete account in the Revue de l'Hypnotisme, January, 1896.