At the time when the Paris Academy of Medicine was condemning animal magnetism, Dr. James Braid, a Manchester surgeon, directed the question into its proper field — that of observation and experiment. Braid must be regarded as the initiator of the scientific study of animal magnetism. For this reason, since it expresses the change of method which he effected, it is usual to substitute for that of animal magnetism the word hypnotism, by which he designated the artificial nervous sleep. Magnetism and hypnotism are fundamentally synonymous terms, but the first connotes a certain number of complex and extraordinary phenomena, which have always compromised the cause of these fruitful studies. The term hypnotism is exclusively applied to a definite nervous state, observable under certain conditions, subject to general rules, produced by known and in no sense mysterious processes, and based on modifications of the functions of the patient's nervous system. Thus it appears that hypnotism has arisen from animal
magnetism, just as the physico-medical sciences arose from the occult sciences of the Middle Ages.
Braid began to observe the results of magnetism merely as an inquirer, and even as a sceptic. In November, 1841, he was present for the first time at some public experiments performed by Lafontaine, a Swiss magnetizer. Convinced that the phenomena which he saw were only due to an adroit imposture, he was anxious to discover by what means the operator was able to dupe his audience. He was soon satisfied that these phenomena, however strange, were quite genuine. But he saw no reason for admitting with Lafontaine that they were the consequence of the operator's personal action on his subject, by means of a magnetic fluid; he rather considered them to be due to a subjective state, independent of all external influence. This was the first result of Braid's researches; he showed that the theoretic fluid was not required to explain hypnotic phenomena.
Braid gives the following account of the way in which he arrived at this discovery. All which he saw at the first magnetic séance left him incredulous. At a second séance, six days later, his attention was struck by the fact that it was not possible for the patient to open his eyes. He regarded this incapacity as a real phenomenon, for which he sought the physical cause; it occurred to him that this cause might be found in the fixed gaze, which has the effect of exhausting and paralyzing the nervous centres of the eyes and their appendages. It signifies little whether this explanation is true or false — it is only a matter of detail; but it is important that Braid should have regarded this first symptom of hypnotism, the spasm of the orbicularis
palpebrarum, as due to a modification of the state of the nervous system. Two days later he began, in the presence of his family and friends, a series of experiments, intended to justify his theory. He tells us that he requested his friend Walker to sit down and look fixedly at the neck of a wine-bottle, which was placed at such a height as to cause considerable fatigue to his eyes and eyelids when he looked at it attentively. In three minutes the eyelids closed, tears flowed down his cheeks, his head drooped, his countenance was slightly contracted, a sigh escaped from him, and at the same moment he fell into a deep sleep. Mrs. Braid was much astonished by the patient's fear and agitation when he awoke, for which she could see no cause, since she had not ceased to watch her husband, and she had seen that he did not approach Walker, nor touch him in any way. Braid proposed that she should herself submit to the operation, to which she readily assented, assuring those present that she should be less easily frightened than the first subject. Braid made his wife sit down and fix her eyes on the ornaments of a porcelain sugar-basin, which was placed at about the same angle with the eyes as that formed by the bottle in the previous experiment. In two minutes the expression of her features was changed; in two and a half minutes the eyelids closed with a convulsive movement, the mouth was distorted, the patient sighed deeply, the chest heaved, she fell back. It was evident that she had passed through a paroxysm of hysteria, and Braid then awoke her.
This account shows that there was nothing complex nor mysterious in the process which caused sleep; it was only necessary for the subject to concentrate his attention
and his gaze for a few minutes on a given object. A brilliant object was sometimes employed, but this was not an indispensable condition.
From this time the reality of somnambulism was established; it became a state subject to observation, which any one could produce at pleasure. Numerous observers since Braid have repeated the experiment of the fixity of gaze, and have reproduced precisely the same phenomena. The simultaneous fixing of the attention appears to be necessary as a rule, and Braid considers that this explains why idiots cannot be hypnotized.
This important discovery throws a vivid light on religious practices which up to that time had been inexplicable. We know that Indian devotees are thrown into an ecstasy of union with God, by contemplating for hours an imaginary point in space. The monks of Mount Athos were addicted to the same practice, fixing their gaze on their navels. These are evidently hypnotic states, produced by the fixity of gaze.
Since he showed that hypnotism could be produced by fixing the eyes on an inanimate object, such as the stopper of a bottle or the blade of a lancet, Braid proved that this nervous state did not necessarily result from the transmission of a fluid by the operator. He had therefore simplified the study of hypnotism by getting rid of all the marvellous phenomena which had discredited it for such a length of time. But Braid's conclusions were too absolute. The first conceptions of things are always simpler than the reality. It would be a mistake to suppose that the personality of the operator never has anything to do with the phenomena displayed
before him. Broca's assertion must not be taken literally, "The subject is not put to sleep; he goes to sleep." The sleep produced by fixing the eyes on a brilliant object sometimes differs in certain points from the sleep produced by personal intervention. We shall soon have occasion to show that in some cases the patient displays a sort of affinity for the person who puts him to sleep, and who touches his bare hands.
Braid pursued his investigations further. His most important discovery relates to the effect produced by a given attitude on the subject's sentiments. When placed in the attitude of anger, with clenched fists, his countenance assumes a menacing expression, and he begins to box; if he is made to imitate the action of sending a kiss, his mouth smiles. So, again, the action of climbing or swimming is produced when the body is placed in the position required for executing the several acts.
These were Braid's two chief discoveries; he also made several observations of which the justice has now been admitted. He ascertained that the character of the sleep was not always the same, but that it consisted of a series of states, varying from a light slumber up to the most profound sleep. He observed that breathing on the face had the singular effect of changing the hypnotic state, and breathing on it for the second time caused the subject to awake. He also observed that the senses, especially those of touch, smell, and hearing, might suddenly become excessively acute in hypnotized subjects, and it appeared to him that this sensorial modification might afford a rational explanation of some of the marvellous effects obtained by professional magnetizers. Finally, he observed that verbal suggestion might produce hallucina-
tions, emotions, paralysis, etc. Suggestion during the waking state, which has latterly been asserted by some writers to be possible, did not escape his notice.
Although so many of his observations were just, Braid's descriptions of hypnotism are not definite; they contain an indiscriminate account of all the symptoms of hypnotism, anaesthesia, hypersesthesia, hallucinations, paralysis, suggestions of theft and other criminal acts, unilateral hypnosis, duplication of the consciousness, etc., as if all these phenomena had not their peculiar conditions, and did not belong to distinct states. Braid's imperfect work has been completed by the Sâlpetrière school, which shows that hypnotism is a nervous condition, presenting characteristics which vary in intensity, if not in their nature, so that it is possible to distinguish the several phases or states in which the action of the subject varies.
In addition to the want of classification betrayed by this disorderly exposition of facts, Braid has erred in putting in one category the unproved and the uncertain, the uncertain and the purely imaginative. A few pages of his book suffice to show that we have to do with a believer rather than with an observer.
Braid has also been blamed for his unsatisfactory experiments in phreno-hypnotism, intended to prove the possibility of exciting special sentiments, ideas, and acts, by pressing on the humps of the skull of a hypnotized subject. The account of these experiments occupies an important place in his Neurypnology. Braid, after taking care to inform us that, while making use of phrenology, he is no materialist, confidently asserts that he could inspire the idea of theft by pressing on the
organ of acquisitiveness; of fighting, by pressing on that of combativeness; of prayer, by pressing on the organ of veneration, etc.
The following experiment was the most curious of the series, and will give an idea of the others. Acquisitiveness was excited, and the subject stole a silver snuff-box from one of the spectators; the pressure was then transferred to the organ of conscientiousness, and the patient surrendered the object with a striking air of contrition. Braid seems to have foreseen the charge of simulation, and he takes care to affirm that several of his phrenological experiments were performed on persons who knew nothing about phrenology, and whose honour was unimpeachable. It is easy, up to a certain point, to understand the strange illusion of which Braid was the dupe. He had not observed the importance of that frequent source of error called unconscious suggestion. It is now known that an indiscreet word uttered before subjects very sensitive to suggestion is enough to show what is expected of them, and to make them act in the sense intended by the operator. A gesture may sometimes produce the same effect, and this explains how, in some public exhibitions, the magnetizer, having agreed with his subject to deceive the spectators, is able to make him obey mental orders without expressing them verbally. There is in reality no communication by thought, but by signs which are comprehended by the subject with extraordinary quickness of perception. In Braid's experiments it is probable that something analogous occurred, although there was no imposture. Braid was doubtless as honest as his subjects, but the latter unconsciously obeyed a gesture or word, or were
unconsciously influenced by the recollection of a previous stance. This seems the more probable assumption, since Braid's subjects were often people in good society, assembled to take part in a séance of phreno-hypnotism, and who, after seeing what Braid effected on others, voluntarily submitted to be the subjects of experiment.
Braid's errors are not, however, wholly devoid of truth. Numerous observers have declared that pressure on the heads of hypnotic subjects produces a surprising variety of sensory and motor effects.
As a physician, Braid was much occupied in applying hypnotism to therapeutics. His observations refer to diseases of the eye, to tic-douloureux, nervous headaches, spinal irritation, neuralgia of the heart, palpitations and irregular action of the heart, epilepsy, paralysis, convulsions, tonic spasms, affections of the skin, rheumatism, etc. We cannot refrain from the belief that here again Braid was deceived in more than one instance, but he must be credited with having made a fairly methodical study of hypnotic therapeutics.
The results of Braid's labours have in our day been considerable. He has the merit of having proved that animal magnetism is a natural phenomenon, a definite nervous condition, produced by means of known processes. Lasègue regards him as an indifferent physiologist. But this matters little, since many more intelligent and liberal minds have not the merit of having discovered a single new fact. Indeed, it appears that a certain narrowness of mind, allied with an obstinate will, is to some extent characteristic of the innovator.*
Braid's discovery had little success in his own country, although it obtained the support of the physiologist Carpenter. In 1842 he submitted his researches to the medical section of the British Association, and offered to repeat his experiments before a special commission. The offer was formally rejected, and the section proceeded to other matters. It was said that this subject, like so many others, must make its way independently of learned bodies. Braid was not discouraged, and became the propagator of hypnotism with the indefatigable ardour which is characteristic of innovators, and which we have lately observed in Burq, the inventor of metallo-therapia. He held many experimental stances in London, Liverpool, and Manchester, without obtaining the justice due to him.
Braid's theory had more success in America, but not under his own name. In 1848 an American named Grimes, who does not appear to have been acquainted with Braid's discovery, showed that most of the hypnotic phenomena could in certain subjects be produced in the waking state by means of verbal suggestion. This theory, which passed in the United States under the somewhat absurd name of electro-biology, reached England in 1830, and produced a new movement in favour of hypnotism.
Although extracts from Braid's works were published by Littré and Robin, by Robin and Béraud, etc., and
there was an article on the subject in the Presse by Meunier, his theories were little known in France.
In 1850 the question was, however, again brought before the French public by Azam, a Bordeaux surgeon. Azam had been called in to see a poor girl who was said to be insane, and who presented the singular phenomena of spontaneous catalepsy, of anaesthesia, and of hyperaesthesia. Azam was acquainted with the magnetic phenomena of artificial somnambulism, and was struck by the correspondence between these and those which occurred spontaneously in his patient. One of his colleagues mentioned to him Braid's experiments, which were reported in Todd's Encyclopedia, and he tried to repeat these experiments on his patient, not without misgivings. He tells us that "at the first attempt, after being subjected for one or two minutes to the usual process, the patient fell asleep: the anaesthesia was complete, and it was evident that she was in a state of catalepsy. Hyperaesthesia afterwards supervened, accompanied by the power of answering questions, and other symptoms indicative of the exercise of the intelligence." * Similar experiments were successfully performed by Azam on another girl living in the same house, for the most part such experiments as had been described by Braid. We quote an instance of suggestions by means of the muscular sense: "If, during the period of catalepsy, I place Mlle. X — 's arms in the position of prayer, and leave them thus for a certain time, she states that her thoughts are fixed on prayer, and that she supposes herself to be present at a religious rite. When placed with folded arms and drooping head, she
chives de Méde.
feels her mind possessed by a series of ideas of humility and contrition. When her head is raised her ideas become haughty." The hyperaesthesia of the senses is no less decided. Azam asserts that the hearing becomes so acute as to distinguish the ticking of a watch at the distance of nine or ten yards: this sensitiveness to noise fatigues the subjects, and an expression of pain passes over the face at the rolling of carriages, the human voice, etc. When a bare hand is placed behind her back, at a distance of forty centimetres. Mile. X — stoops forward and complains of feeling the heat.
Azam was, however, chiefly struck by the general anaesthesia which frequently accompanied the hypnotic sleep. In concert with Broca, he sought in hypnotism a fresh mode of producing anaesthesia during surgical operations. This idea gained ground. Broca remarks that a method which introduces no foreign substance into the system appears to him to be absolutely inoffensive. This, however, is erroneous, since death may be produced by a suggestion. In 1851 Broca and Follin put a woman under hypnotism before making an incision in an abscess in the anus. This fact was communicated to the Academy of Sciences by Velpeau, who, in announcing with satisfaction this "new discovery," appeared to have no doubt that animal magnetism, which had been condemned by the Academy, had reappeared under a new name. A few days later Guérineau, of Poitiers, employed the same hypnotic ansesthesia during the amputation of a thigh. The interest in hypnotism became general, and it was remembered that as early as 1829 Cloquet had amputated the breast of a magnetized woman, and that Loysel had performed very
serious operations under like conditions. It was, however, a transient interest, since the surgeons perceived that the hypnotic sleep could not be produced in all subjects; that even in those most susceptible to it, a series of daily hypnotizations must precede the operation, and that sometimes, instead of producing anaesthesia, the converse effect of hyperaesthesia was produced. These failures were partly due to the fact that it was not then known that suggestion might be used to produce insensibility. Chloroform was, therefore, soon preferred to hypnotism as the safer and more convenient means. The year 1860 witnessed the dawn and decline of the prevailing fashion of employing hypnotism to produce surgical anaesthesia.
The question of animal magnetism, which had been proscribed twenty years before by the Academy of Medicine, was, however, reopened. The reality of the nervous sleep was no longer disputed; the mode of producing it was known, as well as its main symptoms. Distinguished physicians were now anxious to study these phenomena, without fear of compromising themselves. It was at this time that the works of Demarquay, and Giraud-Teulon, Gigot-Suard, Liébault, and Philips (Durand de Gros) appeared.
The chief result of these researches was to confirm Braid's work in essential particulars. It was again proved that the personality of the hypnotizer is not a necessary element in producing the subject's sleep. Demarquay and Giraud-Teulon, in order to ward off the influence of the experimenter's gaze, made use of a polished steel ball, which was mounted on a stalk and fastened to a diadem; this diadem was placed on the
subject's head, and his eyes were consequently drawn into the indicated convergence without the intervention of the experimenter.* It is needless to add that this method produced sleep in the subject, just as other methods did. Gigot-Suard even ascertained that a brilliant object need not be presented to the eyes, and that the fixity of gaze would suffice. It was enough to order the subject to look at his nose, and then immediately to bandage his eyes. This also produced hypnosis.
Demarquay and Giraud-Teulon agreed that a predisposition to hysteria was a general condition of hypnotic effects. In fact, results were only obtained from four persons out of eighteen, and these four were all women; the men submitted to experiment were altogether refractory. Moreover, in one of these women the attempt at hypnotization produced the first symptoms of an hysteric attack. Hence they concluded that the nervous state designated as hypnotism was not physiological, but altogether morbid. The work by Demarquay and Giraud-Teulon is brief, accurate, and full of carefully observed facts, without the mystical tendency which is found in Braid. It is perhaps the first work on hypnotism of a strictly scientific character.
Durand de Gros, better known as Dr. Philips, since he was one of the proscribed of December 2, and assumed this name in order to return to France, delivered public lectures on hypnotism in Belgium, Switzerland, France, and Algeria. In 1860 he published a Cours théorique et pratique de Braidisme, in which, he developed his ideas on the mechanism of hypnosis. But the medical world was not much moved by his abstract conceptions
of the hypotaxic state and of ideoplasticism, of which we will only say a few words. According to this author, the exercise of thought is necessary for the regular diffusion of nervous force into the sensory nerves; the exercise of this mental activity is suspended by hypnotism, or rather is reduced to a minimum by submitting it to the exclusive excitement of a simple, homogeneous, and continuous sensation. Since the nervous force is no longer consumed by thought, it accumulates in the brain, and this sort of nervous congestion is termed the hypotaxic state. But, by a special impression on the sight, the hearing, or the touch, a given point of the brain may be excited, so that all the disposable nervous force may be accumulated on it. The same result may be obtained with a mental impression as with a sensorial impression; it awakens the activity proper to a given part of the brain, and produces the most varied effects. This is ideoplasticism.
Durand de Gros's theories somewhat resemble those set forth five years later by Liébault, a physician of Nancy, in a work entitled, "Sleep, and the states analogous to it, specially considered in the action of the morale on the physique" (Nancy, 1866). In his preface Liébault writes: "In my endeavour to study the passive modes of existence, I have first sought to demonstrate the truth that they are the effects of a mental action, and then to make my readers acquainted with their properties, from the point of view of the action of the morale on the physique." In these words we find the germ of the idea developed by subsequent writers, who wish to prove that all the phenomena of artificial sleep, — both mental and physical phenomena, such as contractions, catalepsy, etc. — are produced by suggestion. Thus, Liébault asserted
that artificial as well as natural sleep was produced by an act of the intelligence, that is, by concentrating the attention on one idea, that of going to sleep. This explanation does not apply to those persons who are hypnotized against their will. Liébault goes further, and maintains that modifications of the attention, its too energetic retreat into the brain, etc., cause the difficulty of breathing, the dilatation of the pupils, the weight of the head, singing in the ears, cyanosis, and the palpitations of the heart which accompany the approach of sleep. In Liébault's opinion, attention appears to sum up the action of the mind oh the physique. Concentration of the attention causes the isolation of the senses, the cessation of muscular movements, the establishment of a rapport between the somnambulist and the operator, catalepsy, etc. The afflux of attention to the organs of the senses increases their power of perception; its accumulation on the "empreintes sensorielles" quickens the memory, and so it is with the other senses. On waking from a state of profound hypnotism, there is oblivion, which is due to the fact that all the nervous force accumulated in the brain during sleep is, on awaking, again diffused throughout the organism; since the nervous force is diminished in the brain, it is impossible for the subject to recall to mind that of which he was previously aware.
Liébault's ideas were, received with incredulity; his mode of practice appeared to be so singular that it was rejected by his colleagues without further examination. He lived in retirement, apart from the medical world, and entirely devoted to his convictions and to his patients, who were almost wholly of the poorer class. It is not
difficult to understand the cause of his failure. His book does not contain any clear and definite account of hypnotism; the symptoms which result from this profound modification of the system are not the object of a methodical study, and his descriptions are vague and without definite character. There is, perhaps, not a single scientific proof of hypnotism in the whole book. Yet we must give Liébault credit for having been a conscientious observer, convinced of the truth of his practice. It is said that his convictions brought him into unpleasant relations with his colleagues, and it is probable that they would never have been accepted without the labours of Charcot and his pupils, who reestablished the study of hypnotism, simply by giving an accurate description of the physical characteristics of some of the nervous states designated by that name. The theories of Braid were now again in the ascendant. Up to 1878 nothing of much novelty was contributed to them. We need only mention the works of Mesnet (1860), of Lasègue (1865), of Baillif (1868), of Pau de Saint-Martin (1869). No advance was made, but the same ground was traversed again. There is a good account of the works of this period in an article by Duval, which appeared in 1874 in the Dictionaire pratique de médicine et de chirurgie. At the same date, Dechambre declared in the Dictionnaire encyclopédique des sciences Médicales that animal magnetism did not exist.
By degrees the question sank into silence and oblivion. The more earnest minds turned away from it, and abandoned the subject to professional magnetizers, who contrived to make money by public exhibitions of
hypnotism. From time to time a man of note attempted to shake off the general indifference, but no response was made. In 1875, Ch. Richet published in the Journal de l’anatomie et de la physiologie the result of some researches on hypnotism, which he had made while house-surgeon of a hospital. Although the paper was interesting and full of facts, it obtained little notice.
At about the same time the somnambulism of animals was studied in Germany. As Richet justly observes: "In order to judge of the question of simulation, nothing can be simpler than to perform experiments on beings incapable of playing a part." But it was ascertained, on setting to work, that the symptoms of somnambulism in animals are by no means strongly marked.
As early as 1646, Father Athanasius Kircher relates, in a book entitled Ars magna lucis et umbrae, that if a cock, with his legs tied together, be placed before a line made upon the floor with white chalk, he becomes at the end of a few moments perfectly motionless; if the string be untied and he is excited, he does not issue from the cataleptic state. This experiment may be of still earlier date, since it has been ascribed to Daniel Sehwenter (1636). However this may be, in many countries the hypnotization of poultry became a popular amusement. In 1872, Czermak carefully repeated these experiments; he hypnotized a cock without making use of the ligature, or of the chalk line, and kept the animal immovable. He extended the experiment to other animals, to sparrows, pigeons, rabbits, salamanders, and crabs.* Preyer,+ whose treatise on the subject is the most
complete which we possess, ascribed most of the phenomena observed under these conditions to fear. This author holds that strong excitement produces the cataleptic state, that is, a paralysis due to fear. For instance, if a lizard's tail, or a frog's foot, is suddenly pinched, the animal becomes petrified, sometimes for several minutes, and is incapable of moving its limbs. Gentle and protracted excitement is needed to effect the hypnosis of animals. If the nostrils of a guinea-pig are kept for some time slightly compressed with a pair of pincers, the animal becomes hypnotic, and is thrown into such a stupor that it can be placed in the most absurd positions without being awakened. This arbitrary distinction between catalepsy and hypnotism has not been accepted. We need only note that many animals can be hypnotized, either by a brief and strong excitement of the skin, or by a repeated and fainter action of the same kind.
The experiments on the frog are interesting, and easy to reproduce. Heubel * has shown that if a lively frog is lightly held between the fingers, with the thumb on the belly, and the four fingers on the back, the animal becomes perfectly motionless at the end of two or three minutes; it may be stretched upon its back, or placed in all sorts of positions, without making any attempt at defence or escape. The same paralytic state may be produced by gently scratching the frog's back. But it must be admitted that none of these facts throw much fresh light on animal magnetism, and we do not, therefore, insist on them further.
We now come to the year 1878, and to the researches of the Sâlpetrière school.
The history of animal magnetism has shown that if, up to late years, the existence of the nervous sleep, and of the various phenomena allied with it, has been doubted, it is chiefly because the experimenters wanted method, and were principally concerned with the study of complex psychical phenomena. Such phenomena often lack the material characteristics which would place them beyond dispute. Since the proofs of these remarkable manifestations were wanting, it was at once concluded that they were, at any rate, hypothetical, if not false.
The disputes and doubts might have gone on indefinitely, but for the intervention of material facts, which it was impossible to interpret in different senses. These material facts could not be at once discovered in the domain of the complex phenomena which had attracted the attention of the early experimenters; they belonged to the purely physical order of things.
We must add that these physical signs of hypnosis have not hitherto been observed in their complete development, except in subjects affected by hysteria. Hence it follows that the hypnotism which first took its place in science is that of hysterical patients, and it is still termed profound hypnotism, both to characterize the intensity of its symptoms, and to distinguish it from, the feebler forms which had, up to that time, been exclusively studied by physicians, and which may now be grouped under the name of slight hypnotism.
The method which led to the revival of hypnotism may be summed up in these words: the production of material symptoms, which give to some extent an anatomical demonstration of the reality of a special state of the nervous system. This is merely an application of
Descartes's rule, that we should go from the simple to the compound. Before adopting this method, we have passed through an age of senseless errors and sterile discussions.
It is to Charcot that the honour must be assigned of having been the first to enter on this course, in which he has been followed by numerous observers. The violence with which he was attacked is a proof of the important part he took in the question. Whatever objections may be made to his description of the different states known under the name of hypnotism, it is certain that the application of the nosographic method to this study enabled Charcot to establish phenomena within the domain of science which had hitherto been regarded as beyond its range. Charcot was not only fortunate enough to establish the scientific value of hypnotism, but to obtain compensation for his earlier academic failures by his triumphant readmission into the Academy of Sciences. *
The researches of the Sâlpetrière school served as the point of departure for a fresh scientific movement, which continues up to the present day.
In 1880, Heidenhain, an eminent German physiologist, resumed the study of hypnotism, prompted by some public performances at Breslau, given by a Danish magnetizer named Hansen. Heidenhain's paper + gave the signal for several other German publications, among
which we may mention that by Grützner,* by Berger, + by Baumler, ++ by Preyer, +++ by Schneider. ++++ In France we find, among others, P. Richer, Bourneville and Regnard, Dumontpallier and his pupils, Ladame, Bottey, Pitres, Bremaud, Bernheim, Beaunis; in Italy, Tamburini and Seppili, and Lombroso ; in England, Hack Tuke.