ANIMAL MAGNETISM. The terms animal magnetism, electro-biology, mesmerism, clairvoyance, odylic or odic force, and hypnotism have been used to designate peculiar nervous conditions in which the body and mind of an individual were supposed to be influenced by a mysterious force emanating from another person. With the exception of mesmerism, a name given to the phenomena in honour of one of their earliest investigators, F. A. Mesmer, each of these terms implies a theory. Thus the phenomena of animal magnetism were supposed to be due to some kind of magnetic force or influence peculiar to living beings and analogous to the action of a magnet upon steel or certain metals ; electro-biology, a more modern term, introduced in 1850 by two American lecturers, referred the phenomena to the action of electrical currents generated in the living body, and capable of influencing electrically the bodies of others; clairvoyance implied a power of mental vision or of mental hearing or of a mental production of other sensations, by which the individual became aware of events happening in another part of the world from where he was, or could tell of the existence of objects which could not affect at the time any of his bodily senses ; odylic force was a term given to a force of a mysterious character by which all the phenomena of animal magnetism might be accounted for; and hypnotism, from hypnos [Gk.], sleep, was a name applied to a condition artificially produced in which the person was apparently asleep and yet acted in obedience to the will of the operator as regards both motion and sensation.
History.It was natural that the apparent power of influencing the bodies and minds of others should attract much attention and be eagerly sought after for purposes of gain, or from a love of the marvellous, or for the cure of diseases. Hence we find that, whilst not a few have investigated these phenomena in a scientific spirit, more have done so as quacks and charlatans who have thrown discredit on a department of the physiology of man of the deepest interest. Recently, however, as will be shown in this article, physiologists and physicians have set about investigating the subject in such a manner as to bring it into the domain of exact science, and to dispel the idea that the phenomena are due either to any occult force or to super-natural agency. It would appear that in all ages diseases were alleged to be affected by the touch of the hand of certain persons, who were supposed to communicate a healing virtue to the sufferer. It is also known that among the Chaldaeans, the Babylonians, the Persians, the Hindus, the Egyptians, the Greeks, and the Romans many of the priests effected cures, or threw people into deep sleeps in the shades of the temples, during which the sleeper sometimes had prophetic dreams, and that they otherwise produced effects like those now referred to animal magnetism. Such influences were held to be supernatural, and no doubt they gave power to the priest-hood. In the middle of the 17th century there appeared in England several persons who said they had the power of curing diseases by stroking with the hand. Notable amongst these was Valentine Greatrakes, of Affane, in the county of Waterford, Ireland, who was born in February 1628, and who attracted great attention in England by his supposed power of curing the kings evil, or scrofula. Many of the most distinguished scientific and theological men of the day, such as Robert Boyle and R. Cudworth, witnessed and attested the cures supposed to be effected by Greatrakes, and thousands of sufferers crowded to him from all parts of the kingdom (see Colquhouns History of Magic, &c., vol. ii. p. 146).
Phenomena of a marvellous kind, more especially such as imply a mysterious or supernatural power exercised by one person over another, not only attract attention, but take so firm a hold on the imagination that belief in them breaks out now and again with all the intensity of an epidemic. Thus since the time of Greatrakes, at short intervals, men have arisen who have led the public captive at their will. About the middle of the 18th century John Joseph Gassner, a Roman Catholic priest in Swabia, took up the notion that. the majority of diseases arose from demoniacal possession, and could only be cured by exorcism. His method was undoubtedly similar to that followed by Mesmer and others, and he had an extraordinary influence over the nervous systems of his patients. Gassner, how-ever, believed his power to be altogether supernatural and connected with religion.
Friedrich (or Franz) Anton Mesmer was born at Weil, near the point at which the Rhine leaves the Lake of Con-stance, on May 23, 1733. He studied medicine at Vienna under the eminent masters of that day, Van Swieten and De Haen, took a degree, and commenced practice. Interested in astrology, he imagined that the stars exerted an influ-ence on beings living on the earth. He identified the sup-posed force first with electricity, and then with magnetism; and it was but a short step to suppose that stroking diseased bodies with magnets might effect a cure. He published his first work (De Planetarum Influxu) in 1766. Ten years later, on meeting with Gassner in Switzerland, he observed that the priest effected cures without the use of magnets, by manipulation alone. This led Mesmer to discard the magnets, and to suppose that some kind of occult force resided in himself by which be could influence others. He held that this force permeated the universe, and more especially affected the nervous systems of men. He removed to Paris in 1778, and in a short time the French capital was thrown into a state of great excitement by the marvellous effects of mesmerism. Mesmer soon made many converts; controversies arose; he excited the indignation of the medical faculty of Paris, who stigmatized him as a charlatan; still the people crowded to him. He refused an offer of 20,000 francs from the Government for the disclosure of his secret, but it is asserted that he really told all he knew privately to any one for 100 louis. He received private rewards of large sums of money. Appreciat-ing the effect of mysterious surroundings on the imagina-tions of his patients, he had his consulting apartments dimly lighted and hung with mirrors ; strains of soft music occasionally broke the profound silence; odours were wafted through the room; and the patients sat round a kind of vat in which various chemical ingredients were concocted or simmered over a fire. Holding each others hands, or joined by cords, the patients sat in expectancy, and then Mesmer, clothed in the dress of a magician, glided amongst them, affecting this one by a touch, another by a look, and making "passes" with his hand towards a third. The effects were various, but all were held to be salutary. Nervous ladies became hysterical or fainted; some men became convulsed, or were seized with palpitations of the heart or other bodily disturbances. The Government appointed a commission of physicians and members of the Academy of Sciences to investigate these phenomena; Franklin and Baillie were members of this commission, and drew up an elaborate report admitting many of the facts, but contesting Mesmers theory that there was an agent called animal magnetism, and attributing the effects to physiological causes. Mesmer himself was undoubtedly a mystic; and, although the excitement of the time led him to indulge in mummery and sensational effects, be was honest in the belief that the phenomena produced were real, and called for further investigation. For a time, however, animal magnetism fell into disrepute; it became a system of downright jugglery, and Mesmer himself was denounced as a shallow empiric and impostor. He with drew from Paris, and died at Meersburg in Switzerland on 5th March 1815. He left many disciples, the most distinguished of whom was the Marquis de Paysegur. This nobleman revolutionized the art of mesmerism by showing that many of the phenomena might be produced by gentle manipulation causing sleep, and without the mysterious surroundings and violent means resorted to by Mesmer. The gentler method was followed successfully by Deleuze, Bertrand, Georget, Rostan, and Foissac in France, and by Dr John Elliotson in England up to about 1830.
In 1815 considerable attention was drawn to tile announcement by Baron von Reichenbach of a so-called new "imponderable" or "influence" developed by certain crystals, magnets, the human body, associated with heat, chemical action, or electricity, and existing throughout the universe, to which he gave the name of odyl. Persons sensitive to odyl saw luminous phenomena near the poles of magnets, or even around the hands or heads of certain persons in whose bodies the force was supposed to be concentrated. In Britain an impetus was given to this view of the subject by the translation in 1850 of Reichenbachs Researches on Magnetism, &c., in relation to Vital Force, by Dr Gregory, professor of chemistry in the university of Edinburgh. These Researches show many of the phenomena to be of the same nature as those described previously by Mesmer, and even long before Mesmers time by Swedenborg. The idea that some such force exists has been a favourite speculation of scientific men having a mental bias to mysticism, and it makes its appearance not unfrequently.
The next great step in the investigation of these phenomena was made by James Braid, a surgeon in Manchester, who in 1811 began the study of the preten-sions of animal magnetism or mesmerism, in his own words, as a "complete sceptic" regarding all the phenomena. This led him to the discovery that he could artificially produce "a peculiar condition of the nervous system, induced by a fixed and abstracted attention of the mental and visual eye on one object, not of an exciting nature." To this condition he gave the name of neuro-hypnotism (from neuron [Gk.], nerve, hypnos [Gk.], sleep) ; for the sake of brevity, neuro was suppressed, and the term hypnotism came into general use. Braid read a paper at a meeting of the British Association in Manchester on 29th June 1842, entitled Practical Essay on the Curative Agency of Neuro--Hypnotism; and his work Neurypnology, or the Rationale of Nervous Sleep considered in relation with Animal Magnetism, illustrated by numerous cases of its successful application in the relief and cure of disease, was published in 1843. It is necessary to point this out, as certain recent Continental writers have obtained inany of Braids results by following his methods, and have not adequately recognized the value of the work done by him forty years ago. Braid was undoubtedly the first to investigate the subject in a scientific way, and to attempt to give a physiological explanation. In this he was much aided by the physiologist Herbert Mayo, and also by Dr William B. Carpenter,the latter being the first to recognize the value of Braids re-searches as bearing on the theory of the reflex action of the ganglia at the base of the brain and of the cerebrum itself, with which Carpenters own name is associated.
Recently the subject has been reinvestigated by Professor Weinhold of Chemnitz, and more particularly by Dr. Rudolf Heidenhain, professor of physiology in the university of Breslau, who has published a small but interesting work on animal magnetism. In this work Heidenhain attempts to explain most of the phenomena by the physiological doctrine of inhibitory nervous action, as will be shown hereafter.
Phenomena and Physiological Explanation.The usual method of inducing the mesmeric or hypnotic state is to cause the person operated on to stare fixedly at a faceted or glittering piece of glass held at from 8 to 15 inches from the eyes, in such a position above the forehead as will strain the eyes and eyelids. The operator may stand behind the patient, and he will observe that the pupils are at first contracted from the effort of accommodation of each eye for near vision on the object; in a short time the pupils begin to relax, and then the operator makes a few "passes" over the face without touching it. The eyelids then close; or the operator may gently close them with the tips of the fingers, at the same time very gently stroking the cheeks. Often a vibratory motion of the eyelids may be observed when they are closed, or there may be slight spasm of the eyelids. The eyes may afterwards become widely opened. The patient is now in a sleep-like condition, and the limbs often remain in almost any position in which the operator may place them, as in a cataleptic con-dition. At the same time the patient may now be caused to make movements in obedience to the commands of the operator, and to act according to ideas suggested to him. Thus, he may eat a raw onion with gusto, apparently under the impression that it is an apple ; he may make wry faces on drinking a glass of water when told that what he is taking is castor oil; he may ride on a chair or stool as in a horse race; he may fight with imaginary enemies, or show tokens of affection to imaginary friends ; in short, all kinds of actions, even of a ridiculous and a degrading nature, may be done by the patient at the command of the operator. Another class of phenomena consists in the production of stiffness or rigidity of certain muscles or groups of muscles, or even of the whole body. For example, on stroking the fore arm it may become rigid in the prone or supine condition ; the knee may be strongly bent, with the muscle3 in a state of spasm; the muscles of the trunk may become so rigid as to allow the body to rest like a log, head and heels on two chairs, so stiff and rigid as to bear the weight of the operator sitting upon it ; or various cataleptic conditions may be induced and as readily removed by a few passes of the hand. Many disorders of sensation have been observed, such as defective colour perception, the hearing of special sounds which have no objective existence, or deafness to certain tones, or perverted sensations, such as tingling, prickling, rubbing, &c., referred to the skin. The patient may remain in this condition for an hour or more, and may then be roused by holding him for a few minutes and blowing gently into the eyes. Usually the patient has a vague recollection, like that of a disturbed dream, but sometimes there is an acute remembrance of all that has happened, and even a feeling of pain at having been compelled to do ridiculous actions. Certain persons are more readily hypnotized than others, and it has been observed that, once the condition has been successfully induced, it can be more easily induced a second time, a third time more easily than a second, and so on until the patient may be so pliant to the will of the operator that a fixed look, or a wave of the hand, may throw him at once into the condition. Such are the general facts in artificially induced hypnotism, and they belong to the same class as those referred to animal magnetism, electro-biological effects, odylic influences, &c., according to the whim or theory of the operator.
It is not surprising that such phenomena have been the cause of much wonder and the basis of many superstitions. Some have supposed that they were supernatural, others that they indicated the existence of a specific force exerted by the experimenter upon the passive subject. Many operators have no doubt believed they possessed such a force; such a belief would not affect the success of their experiments except to make them more likely to be succesIsful, as the operator would readily comply with all the conditions; but most of these phenomena can be explained physiologically, and those which cannot be so accounted for will remain hidden until we get further light on the physiology of the nervous system.
The symptoms of the hypnotic state, as shown by Heidenhain, may be grouped under four heads(1) those referable to conditions of the sensorium or portion of the brain which receives nervous impulses, resulting in inove-ments of a reflex and imitative character; (2) insensibility to pain, and various forms of perverted sensation ; (3) increased irritability of the portion of the nervous system devoted to reflex actions ; and (4) states of the nervous centres controlling the movements of the eye, the accommodation of the eye to objects at various distances, and the movements of respiration, &c.
1. The State of the Sensorium.By the sensorium is meant that portion of the nervous system which receives impulses from. the nerves coming from the organs of sense, such as those from the eye, ear, nose, tongue, and skin. Each of these nerves brings its message to a portion of the central nervous system in intimate connexion with the rest of the nervous system. This message may possibly arouse nervous actions associated with consciousness, or it may not; or the nervous actions of consciousness may be so transient as to leave a faint impress on the memory, so that it can be revived only if no great interval has elapsed since the impression was made on the sense organ. If, however, the impression be vivid, then it may be revived long afterwards. This impression may be consciously perceived, and then any apparent effect may end; but it may set up a set of actions, resulting in motion, which are apparently of a reflex character. Thus, suppose a person in the dark ; light is suddenly brought before the eye; this affects the retina, and through the changes in it the optic nerve and central organ; there may be consciousness or there may not; if the person be wide awake he will see the light; if he be asleep he will not see it, at all events he will give no indication of seeing it ; on awaking, he may have a recollection of a dream in which light has a place, or his memory may be blank; but nevertheless the light will cause the pupil of the eye to contract by reflex action without his consciousness; and perhaps, also, without consciousness, the sleeping person may make an effort to avoid the light, as has been noticed in the case of somnambulists.
Now, when a patient has been thrown into a weak hypnotic state, there may be a vivid recollection on awaking of all that happened during the apparent sleep. This implies, of course, that conscious sensory perceptions took place during the condition. Memory depends on the direction of the attention to sensations. If the effort of attention be strong, the recollection will probably be vivid, and the converse is true. But this does not preclude the supposition that sensory perceptions may come and go, like the shadows of clouds on a landscape, without any attempts at fixing them, and consequently with no recollection following their occurrence. The sensory perceptions may have existed for so short a time as to leave no impress behind. This may explain how it is that in the deeper forms of hypnotism there is either no recollection of what occurred or the recollection can only be aroused by hints and leading questions. Attention is necessary, therefore, to form a conscious idea arising out of a sensation.
It is generally admitted by physiologists that the cerebral hemispheres are the seat of the higher mental operations, such as attention, &c., although the interdepend-ence of these hemispheres with the lower sensory ganglia, which receive all sensory impressions in the first instance, and with motor ganglia, which are, in like manner, the starting-points of motor impulses, is not understood. The one portion of the nervous system may work without the other. Thus, during free cerebral activity we pay little attention to what we see or hear, and consequently we remember nothing. A man in a reverie may have many impressions of sight or of hearing of which he has been really unconscious. On the other hand, the cerebral apparatus may be so attuned with the recipient portion that if the latter receives a message the former sympa-thetically responds. For example, a mother sound asleep is disturbed by the slightest cry of her child, although loud sounds of other kinds may not awake her.
It would appear then that impressions on the senses and the consciousness of impressions are two separate states which may occur in a manner independently; that is to say, there may be purely sensory operations, in which consciousness is not involved, or there may be the conscious repetition of old impressions, or what is called memory. Now it is a law of nervous action that processes which at first are always of a conscious kind may by repetition become so habitual as to be performed without consciousness. Thus a child learns to perform a piece of music on the pianoforte by conscious efforts, often of a painful kind ; each note has to be recognized, and the appropriate muscular movements required for its production on the instrument executed with precision and delicacy; but by and by the music may be performed accurately even while the attention is directed to something else. In like manner, all movements which are the results of sensory impressions may become unconscious movements ; the sensory impressions are at first paid attention to ; but as they become habitual the mind becomes less and less engaged in the process, until the movements resulting from them are practically unconscious. A familiar illustration is that of a man in deep reverie walking along a street. Immersed in thought, he pays little or no attention to passers by ; as his eyes are open, their images, or those of adjacent objects, must affect his visual apparatus, but they arouse no conscious impression, and still those impressions, evanescent as they are, are sufficient to excite the appropriate movements of locomotion. These movements are in all respects like voluntary movements, but they are not really voluntary, showing that, by the machinery of the nervous system, movements like voluntary movements inay be executed without volition. It is important to observe, however, that these movements are the result of sensory impressions. A man in the deepest reverie, with his eyes blindfolded, could not execute the requisite movements; and when we see the blind walking in the streets, they afford no contradiction to this view, as their minds are busily engaged in noticing another set of sensory impressions derived from the sense of touch, muscular movement, and hearing, a set of impressions of the greatest importance to them, although of little importance comparatively to ordinary people, who are guided chiefly by visual impressions.
A person in a state of hypnotism may be regarded as in a condition in which the part of the nervous apparatus associated with conscious perception is thrown out of gear, without preventing the kind of movements which would result were it really in action. Impres-sions are made on the sensory organs; the sensory nerves convey the impression to a part of the brain ; in the deepest condition of hypnotism these impressions may not arouse any consciousness, but the result may be the kind of movement which would naturally follow supposing the person had been conscious. The movernents made by the hypnotic are chiefly those of an imitative kind. It has often been noticed that the mere suggestion of the move-ment may not be enough to excite it; to secure success, the movement must be made before the eyes of the person. For example, it is a common part of the exhibition of such persons for the operator to clench his fist; the patient at once clenches his ; the operator blows his nose ; the patient does likewise ; but if the operator performs these actions behind the back of his patient the chances are that the patient will not repeat the movements.
The condition seems to be one in which the sensory impression leads to no conscious perception and to no voluntary movement, but is quite sufficient to arouse those nervous and muscular mechanisms which lead to unconscious imitation. The patient is in a sense an automaton played upon by the operator through the medium of the patients sensory organs. It is important to observe that in deep hypnotism the patient has no idea corresponding to the movements be makes in obedience to the example of the operator. For example, suppose he is swallowing a glass of water and the operator tells him it is castor oil, at the same time making the requisite grimaces, the patient will imitate these grimaces without having any idea either of water or of castor oil. The grimaces are purely imitative, without any connexion with the idea which would naturally excite them. This is the case only with those deeply hypnotized. In some cases, however, the hypnotism is so deep as to resemble coma, and in these there is no trace of any sensory impressions or of movements. In cases where the hypnotism is slight, there may be a curious mixture of effects. Here the patient may be partially conscious of the requests made to him, and of the imitative movements executed before his eyes ; to some extent he may resist the commands of the operator, he may feel he is being fooled, and yet he may perform many ridiculous actions; and when he awakes he may have a vivid recollection of the events in which he participated. A hypnotized person, in fact, is in a state similar to that of the somnambulist, who acts the movements of a disturbed dream. There are many degrees of the sleeping state, from the profound condition resembling coma to that of the light sleeper who starts with every sound. In some sleeps there are dreams in which the sleeper is so occupied with the phantoms of thought as to pay no attention to external impressions, unless these be sufficiently powerful to awake him, whilst there are other sleeps in which the boundary between the conscious reception of new impressions and the reproduction of old ones is so thin as to permit of a blending of the two. In this kind of sleep, a spoken word, a familiar touch, the suggestion of something in keeping with the thoughts of the dreamer, are sufficient to change the current of the dream, and even to excite movements. When the ideas of the dreamer cause movements corresponding to these ideas, then the dreamer becomes a somnambulist. He acts the dream; according to the depth of the semi-conscious state will be his capacity for responding to external impressions. Some somnambu-lists respond to external suggestions readily, others do not ; and in all there is almost invariably no recollection of the state. Artificial hypnotism is a condition of the same kind, though usually not so profound.
The question now arises as to how this artificial state may be induced. In one awake and active, all sensory impressions as a rule are quick, evanescent, and constantly renewed. New successions of images and thoughts pass rapidly before the mind during walking, working, eating, or in the leisure hours of social life ; but none last so long as to cause fatigue of any particular part of the body. By and by there is a general feeling of fatigue, and then sleep is needed to restore exhausted nature. But if the attention be fixed on one set of sensory impressions, fatigue is much sooner experienced than if the impressions are various in kind and degree. Thus one or two hours spent at a picture gallery or at a concert, if the attention be devoted to the impressions on the eye or ear, usually cause fatigue. It would appear that the method of exciting hypnotism by causing the patient to gaze at a bit of glass or a bright button depends in the first place on the feeling of fatigue induced. At first there is a dazzling feeling; then the eyes become moist ; images become blurred and indistinct, and seem to swim in the field of vision ; the field of vision becomes unsteady, and just about this period ideas do not pass in the mind in orderly sequence, but irregularly, as in the few minutes immediately before passing into sleep, At this stage also the pupils become widely dilated, and the eyeballs become more prominent than usual. The innervation of the iris must be understood, so as to appreciate the physiological meaning of these changes. The muscular structure of the iris is supplied by two, nerves, the third cranial nerve and the sympathetic nerve. If the third nerve be cut the pupil dilates ; if the distal end of the nerve be irritated the pupil contracts. On the other hand, if the sympathetic nerve be cut the pupil contracts, whilst if the distal end be irritated the pupil dilates. These experimental facts show that the radiating fibres of the iris which dilate the pupil are under the control of the sympathetic nerve, whilst the circular fibres which contract the pupil are supplied by the third. Further it can be shown that the corpora quadrigemina, two ganglionic masses in the brain, are the reflex centres for the regulation of these movements. The optic nerve from the retina supplies the sensory stimulus which causes, the pupil to contract. Thus, suppose light to be brought before the eye while the pupil is dilated ; the retina is, affected, a stimulus is sent to the corpora quadrigemina, along the fibres of the optic nerve, and from the corpora quadrigemina a nervous influence passes along the fibres of the third nerve to the circular fibres of the iris, causing the papil to contract. It is also very probable that the corpora quadrigemina act as reflex centres for nervous impulses regulating the calibre of the blood-vessels of the eye, the vaso-motor nerves. If we apply these facts to tha case of a hypnotized person, we find that (1) the pupil of a hypnotized person contracts energetically when light falls upon the eye, showing that the reflex mechanism is still intact; (2) just before the hypnotic state is induced the pupil dilates, indicating feeble nervous impulses passing along the third from the corpora quadrigemina; (3) at first, the eyeballs seem to sink in, but when hypnotism is complete they project in a manner similar to what has been observed in an animal when the arteries supplying the head have been compressed so as to make the brain anaemic or bloodless; and (4) the ophthalmoscope has, not shown any change in the calibre of the blood-vessels of the retina in the hypnotic state. From a consideration of these facts and inferences Heidenhain was at first inclined to believe that hypnotism might be due to a reflex influence on the vessels of the brain, causing them to contract so as to permit the passage of only a small quantity of blood, and make the brain anaemic. This view, however, had to be abandoned, as the faces of hypnotized persons are usually red, and not pale, as they would be were the arterioles contracted. Further, Heiden-hain performed a crucial experiment by giving to his brother nitrite of amyl, which causes dilatation of the vessels by vaso-motor paralysis, when he still found hypnotism could be readily induced, showing that the state was not caused by deficient blood supply.
Heidenhain has advanced another and more probable hypothesis. During the past twenty years a new mode of nervous action, known as inhibitory action, has been discovered by physiologists. A good example is supplied by the innervation of the heart. This organ has nervous ganglia in its substance by which its rhythmic contractions are maintained. Further it is supplied by the vagus or pneumogastric nerve and by the sympathetic. Section of the vagus is followed by quickening of the hearts action, and stimulation of the lower end causes slowing and, if the stimulation be strong enough, stoppage of the heart, not, however, in a tetanic state (which would be the case if the fibres of the vagus acted directly on the muscular structure of the heart, as a motor nerve), but in a state of complete relaxation or diastole. Opposite results follow section and stimulation of the sympathetic fibres. It has been clearly made out that the terminal fibres of both nerves do not act on muscular fibres but on ganglion cells, those of the vagus "inhibiting" or restraining, whitst those of the sympathetic "accelerate" the action of the cells. Inhibition is now known to play an important part in all nervous actions, and it would seem that any power-ful impression in a sensory nerve may inhibit or restrain motion. This is strikingly seen in some of the lower animals. A ligature applied loosely round the thigh of a frog whilst it lies on its back apparently deprives it of all power of motion. The weak sensory stimulation in this case seems to stop voluntary motion. Pressure on the internal organs of such animals as the rabbit, although gentle, sometimes causes paralysis of the lower or hinder limbs. Again, it has been ascertained that, whilst the spinal cord is the chief reflex centre, the reflex activity can be inhibited by impulses transmitted to it from portions of the cerebral hemispheres which are in a state of high activity. It would appear then that, if we suppose one set of sensory or recipient cells in the brain to be brought into a state of exalted irritability by the preliminary operations of hypnotism, the result might be inhibition of the parts devoted to voluntary movement. In like manner, the activity of sensory nerve cells may become inhibited. Thus stimulation of a certain cutaneous area, say the arm, by a mustard plaster, has been found to lower the sensibility of the corresponding portion of skin on the opposite arm. The theory then offered is that "the cause of the phenomena of hypnotism lies in the inhibition of the activity of the ganglion-cells of the cerebral cortex, . . . the inhibition being brought about by gentle prolonged stimulation of the sensory nerves of the face, or of the auditory or optic nerve."
According to this view, the portion of the brain devoted to voluntary movements is as it were thrown out of gear, and the movements that follow, in the hypnotic state, are involuntary, and depend on impressions made on the senses of the patient. To understand how this is possible, we must now consider shortly some of the views presently held as to the action of the brain. The researches of Hitzig, Fritsch, Ferrier, Hughlings Jackson, and many others indicate that certain movements initiated as a consequence of perception, and of the ideas thereby called forth, are due to nervous actions in the grey matter in certain areas on the surface of the cerebral hemispheres, and that there is another class of movements which do not require the agency of the cortex of the brain, but depend on the activity of deeper centres. These deeper centres are the optic thalami, which receive sensory impressions from all parts of the skin; the corpora quadrigemina, which receive luminous impressions from the retina; and the corpora striata, which are the motor centres whence emanate influences passing to the various groups of muscles. No doubt other sensory centres exist for hearing, taste, and smell, but these have not been clearly ascertained. In the case of conscious and voluntary movements carried out as the result of external impres-sions, the excitation would pass first to the thalami optici (tactile) or corpora quadrigemina (visual), thence to the cerebral hemispheres, where ideas would be called forth and volitional impulses generated; these would then be transmitted downwards through the corpora striata (motor) to the crura cerebri and spinal cord, and from thence to special groups of muscles, thus causing specific movements. Suppose now that the portions of cerebral hemispheres connected with ideation and volition were thrown out of gear, and that a similar sensory impression was made on the person ; again the path of nervous impulses would be to the thalami optici (tactile) or corpora quadrigemina (visual), and from thence directly through corpora striata (motor) to crura cerebri and spinal cord, then passing out to muscles, and causing movements as precise as those in the first in-stance, and apparently of the same character. The difference between the two operations, however, would be this:in the first there would be movements following perception, idea-tion, and volition; in the second the same class of move-ments would be effected by anautomatic mechanism without any of the psychical operations above alluded to. This theory has the merit of simplicity, and is in accordance with most of the facts. The chief difficulty in the way of accepting it is to understand why, if hypnotism be so induced, it is not induced much oftener. One would suppose that, if gazing at a coin and having a few passes made with the hand were sufficient to bring about physiological changes of such importance, men would be oftener bypnotized in daily life than they are. But it is to be remembered that attention is seldom fixed on one object so long as in the experiment of producing hypnotism. The first occasion the experiment is made, even with so-called susceptible persons, the time occupied may be from 10 to 20 minutes, and during all that time the attention is on the strain, and feelings of fatigue are excited in the way above described. Again it is well known that sudden and strong sensory impressions often paralyse voluntary action for a time, even in ordinary life, and what is called "presence of mind" really means that power of self-control which prevents the bodily energies being paralysed by strong sensory impressions. A carriage bearing down on a nervous lady in a crowded street may deprive her of all power of movement, or she may automatically run here or there in obedience to the shouts of the bystanders ; but one with coolness can thread her way among the vehicles without fear or trouble.
A hypnotized person is therefore to be regarded as an automaton. "To cause him to move his arm, the image of a moving arm must pass over his retina, or an unconscious sensation of motion must be induced through passive movement of his arm."
2. Insensibility to Pain.It Ins often been noticed that in the mesmerized or hypnotized person there may be complete insensibility to pain, so that deep pricks with a needle are not felt. During deep hypnotism a pin may be run into the hand without pain, but pain will be felt on awaking, and pulling out the pin in the waking state will cause acute pain. It would appear that certain nerves may convey tactile sensibility whilst others convey only painful impressions, and in certain forms of paralysis the patient may have tactile sensibility without pain, or the reverse. In hysterical women, as has been shown by Charcot and others, disorders of sensibility of this kind are not uncommon, indicating changes in the nervous centres.
3. Increased Reflex Spasm of Muscles.One of the most striking phenomena of the hypnotic state is the ease with which certain voluntary muscles may be rendered stiff. For example, if the operator stroke the skin over the biceps muscle in the upper arm, the limb will be at once power-fully flexed, and the biceps can be felt stiff and rigid. To understand the physiological explanation offered of this phenomenon it will be necessary shortly to describe the mechanism of reflex acts. If a sensory nerve be irritated at its periphery, say in the skin, a nervous impulse ia trans-mitted to a central nervous organ, such as the spinal cord, and through the agency of nerve cells in this organ impulses are then transmitted by motor nerves to muscles, causing movements, without any operation of the will. Thus a particle of food getting into the larynx irritates sensory nerves of the vagus, and there is a reflex spasm of various muscles of expiration, causing a violent cough. That such reflex acts not only can occur without the will, but in spite of it, is shown by the want of control over a sneeze when the nostril is irritated by snuff. Now these reflex centres in the cord are partially under the control of higher centres in the brain. If the agency of the latter be removed, the activity of the cord-centres is increased, and reflex actions are more easily induced. This we have assumed to be the state of the hypnotic. If a portion of his skin be stroked, first one muscle, say the one immediately under the skin stroked, will become stiff, then in obedience to a law regulating reflex actions,namely, that they tend to become diffused according to the strength and duration of the stimulus,other muscles become rigid, and so on until the whole trunk becomes cataleptic. This phenomenon is so well described by Heidenhain that we quote as follows (pp. 23, 24):
"With slight increase of reflex irritability, those muscles alone contract which lie immediately under the area of skin which has been stroked. In this condition it is easy to bring single useles and groups of muscles into isolated action, and thus demonstrate their special motor function. Stroking the ball of the thumb causes adduction of the thumb (towards the palm). Stimulating the skin over the sterno-mastoid causes the head to assume the well-known oblique position which it has when one has got a "stiff neck"; stroking the skin at one corner of the mouth leads to distortion of the month on that side, owing to the contraction of the muscles inserted there. When the irritability is somewhat more increased, we are able, by continuous irritation of a defined group of skin, to set in activity neighbouring and distant groups of muscle, according to the degree of irritation. Thus, when I gently stroke the ball of the thumb, only the flexors and the adductors of this member are set in activity. If I stroke somewhat harder, the forearm muscles, especially the flexors of the fingers, contract. Our patient can, however, still bend and stretch his arm at the elbow, the upper arm museles being still unaffected. Through further increase of the irritation, the latter too and the shoulder muscles are thrown into spasm, so that the whole limb appears immovably fixed. But the highest degree of reflex irritability is not yet attained. Mr A. Heidenhain sits quietly here on a chair. I now once stroke the ball of his left thumb. Please observe the exact succession in which the spasm slowly spreads from one part of the body to the other. You will see the following muscle groups successively affected, some seconds intervening in the passage from one group to another:left thumb, left hand, left forearm, left upper arm and shoulder, right shoulder and arm, right forearm, right hand, left leg, left thigh, right thigh, right leg, muscles of mastication, muscles of the neck. But now I must put an end to it. I strike forcibly the left arm, and the rigor at once disappears. Instant relaxation of the whole body occurs also when I forcibly extend a finger of the clenched fist. Probably the reflex excitement would extend still farther, but I naturally consider it out of the question to try whether the muscles of respiration would become affected. It is easily understood that such experiments require the greatest caution, and may be very seldom carried out."
This condition of the muscles is exactly like that in catalepsy, a peculiar nervous disease; and hypnotism may be regarded as an artificial catalepsy.
4. Other Peculiar Nervous Phenomena of the Hypnotic State.The changes in the eyes have been already alluded to. The pupils dilate, the eyelids open widely, and the eyeballs protrude. Occasionally the upper eyelid droops, so that the eyelids seem closed. It has often been asserted that clairvoyants see with the eyelids closed, but they are really partially open. The movements of respiration are often quickened from 16 to 30 or 35 per minute, indicat-ing stimulation of the respiratory centres in the medulla oblongata. Sometimes the flow of saliva is increased. Hallucinations of sense may occur, though they are rare. One man in the hypnotic state experienced a strong odour of violets.
There is a class of phenomena referred to the hypnotic state of a very doubtful character, inasmuch as we have to depend entirely on the statements of the person operated on, and no objective tests can be employed. Such, for example, are various disturbances of sensation, hearing with the pit of the stomach more acutely than when the sound is made in the usual ways towards the ear, and the application of the hand of the operator to the body giving rise to profound sleep or dreams, induced dreaming, &c. Again it is asserted by Heidenhain and Grützner (Breslauer Aerztl. Zeitsch., No. 4, 28th February 1880) that unilateral hypnosis is possible. Thus stroking the left forehead and temple caused immobility of the right arm and leg.
"Stroking on both sides causes catalepsy of all four limbs ; no facial paralysis or aphasia. Unilateral stroking causes crossed catalepsy and facial paralysis, accompanied when on the left by aphasia. If in addition to unilateral stroking, and this being still maintained, the other side be stroked, then the same result is brought about as if both sides had been stroked from the begin-ning. . . . Measurement of the volume of the arm by means of Mossos volumeter [an instrument for estimating the bulk of the limb by displacement of water and movements of a recording lever] proves that in the cataleptic arm the quantity of blood (in con-sequence of the vascular contraction) sinks enormously, whilst it simultaneously rises in the other arm. When the catalepsy is gone by, the quantity of blood in the cataleptic arm increases, whilst in the other arm it sinks" (Heidenhain, p. 91).
Charcot has pointed out that in certain kinds of hysteria in women there are remarkable unilateral disturbances or perversions of sensory impressions of colour. Pheno-mena of the same kind have been observed by Cohn, Heidenhain, and others in hypnotized persons. Thus A. Heidenhain became completely colour blind in the eye of the cataleptic side. All colours appeared grey in different degrees of brightness, from a dirty dark grey to a clear silver grey.
"If one eye be treated with atropin, whilst the effect of the latter is making its appearance, the phenomena of colour blindness are changed as follows:red and green still appear as different shades of grey ; blue and yellow, on the other hand, do not appear grey. They appear differently in the different stages of atropin action:first stage, yellow appears grey, with a glimmer of blue ; second stage, yellow appears pure blue; third stage, yellow appears blue with a slight tinge of yellow, somewhat as in the so-called struggle of the fields of vision,yellow is seen, as it were, through blue mist ; fourth stage, yellow appears mostly yellow, with tinge of blue. When blue is tried, the corresponding result is obtained ; that is, at last blue with a slight yellow tinge is seen. During the action of atropin the sensation of yellow or blue passes from grey through the contrast colour to the right colour, whilst red and green only appear as different shades of grey" (Heidenhain, p. 95).
These facts are interesting as showing perverted sensa-tion in the particular individual affected, but they throw no light on the condition of hypnotism.
It is evident then that animal magnetism or hypnotism is a peculiar physiological condition excited by perverted action of certain parts of the cerebral nervous organs, and that it is not caused by any occult force emanating from the operator. Whilst all the phenomena cannot be accounted for, owing to, the imperfect knowledge we possess of the functions of the brain and cord, enough has been stated to show that just in proportion as our knowledge has increased has it been possible to give a rational explanation of some of the phenomena. It is also clear that the perverted condition of the nervous apparatus in hypnotism is of a serious character, and therefore that these experiments should not be performed by ignorant empirics for the sake of gain, or with the view of causing amusement. Nervous persons may be seriously injured by being subjected to such experiments, more especially if they undergo them repeatedly ; and it should be illegal to have public exhibitions of the kind alluded to. The medical profession has always been rightly jealous of the employment of hypnotism in the treatment of disease, both from fear of the effects of such operations on the nervous systems of excitable people, and because such practice is in the border land of quackery and of imposture. Still in the hands of skilful men there is no reason why the proper employment of a method influencing the nervous system so powerfully as hypnotism should not be the means of relieving pain or of remedying disease.
Literature.A very complete bibliography will be found appended to the article "Mesmérisme," Dictionnaire Encyclopédique des Sciences Médicalcs (deuxième série, 1873). In addition, see Braid, Neurypnology, London, 1843 ; Elliotson, Human Physiology London, 1840 ; Colquhoun, History of Magic, Witchcraft, and Animal Magnetism, London, 1851 ; Mayo, Letters on the Truths contained in Popular Superstitions, with an Account of Mesmerism, Edinburgh, 1851 ; Scoresby, Zoistic Magnetism, London 1849 ; Hughes Bennett, Lecture on the Mesmeric Mania of 1851, Edinburgh, 1851 ; Reichenbach, Researches in Magnetism, Electricity, Heat, Light, Crystallization, and Chemical Attraction, in their relation to Vital Force (translated by Dr Gregory, London, 1850 ; in this volume the doctrine of odylic force is set forth); Andrew Buchanan, Darlingism, misnamed Electro-Biology, London, 1851 ; Alexander Wood, What is Mesmerism? Edinburgh, 1851, Weinhold, Seven Lectures on Somnambulism, translated by J. C. Colquhoun, Edinburgh, 1845 ; John Forbes, Illustrations of Modern Mesmerism, London, 1845. See also Maudsley, Physiology of Mind, London, 1876 ; and especially Carpenter, Mental Physiology, p. 547 sq. (where the author attempts to account for many of the phenomena by the theory of a dominant idea influencing and governing all other mental operations), London, 1874. The most recent account of these phenomena will be found in Heidenhains Animal Magnetism, translated by Wooldridge, with a preface by G. J. Romanes, London, 1880. For a short and clear account of hysteria as bearing on the phenomena of hypnotism, see Rosenthal, Clinical Treatise on the Diseases of the Nervoas System, vol. ii. p. 29 sq., London, 1881. (J. G. M.)
The above article was written by John Gray McKendrick, M.D., LL.D., F.R.S.; Professor of Physiology, Glasgow University; Fullerton Professor of Physiology at the Royal Institute of Great Britain; President of Physiological Section of British Association; author of Animal Physiology, A Text-Book of Physiology, Life in Motion, or Muscle Nerve, Physiology, Life of Helmholtz, etc.