Popular Science Monthly/Volume 18/January 1881/Artificial Hypnotism
By Dr. R. HEIDENHAIN,
OF THE PHYSIOLOGICAL INSTITUTE OF BRESLAU.
THE people of the city of Breslau were, several months ago, greatly-excited over the performances of a professor of animal magnetism who seemed to exercise extraordinary power. His subjects were taken indiscriminately from his audiences, and all, even physicians and men of science, who allowed themselves to be experimented upon, yielded to his control and contributed to his triumph. Dr. R. Heidenhain, Professor of Physiology and Director of the Physiological Institute of Breslau, on the invitation of the friends of science, delivered a lecture on the subject, in which he undertook to give a physiological explanation of the strange effects obtained by the magnetizer, and showed by experiment that the same results could be obtained by the sight or presence of inanimate objects. The following is an abridged translation of this address.—[Ed.
One of the essential symptoms of the hypnotic sleep is the more or less complete loss of consciousness. It is only in a complete state of hypnotism that persons subjected to the experiment preserve a remembrance of what has passed during their sleep. In some cases the memory is only suspended, and on awaking we may be able to revive the recollection by evoking an association of ideas which will put the subject in train. Sensorial perceptions take place even in the most complete hypnotism, but the power of transforming them into conscious representations, and consequently of fixing them in the memory, is absent. Have we not often had experience in the waking state of external perceptions which did not pass the threshold of consciousness because our attention was absorbed or distracted at the time? Have we not heard words pronounced around us to which we attached no meaning, which were nevertheless perceived by us, if we may speak in that manner, without our knowledge, since we may call them to mind by an effort of memory, provided they have not yet been effaced by a more recent impression?
The immediate affection of the senses and conscious perception are distinct physiological conditions, the latter of which supposes a holding of the attention. As the hypnotic's faculty of perceiving a sensation declines, his power of being conscious of it diminishes in a corresponding degree. Then, sensorial impressions which do not excite consciousness give way to movements which are accomplished almost without our control. A person walking in the street, absorbed in his thoughts, receives the visual impression of the passers-by on his retina without paying attention to them, and unconsciously performs the movements necessary to avoid hitting them. The hypnotic is in a similar situation. Sensorial impressions of which he is not conscious provoke apparently voluntary and reasoned acts.
The hypnotic, although his eyes are shut, perceives what is passing around him. The eyelids are not wholly closed. Movements perceived unconsciously, by the aid of the sight or hearing, are imitated by him involuntarily and under a constraint from which he can not withdraw himself, and with an almost servile exactness. Thus he will regulate his step according to that of the experimenter who makes him act, will raise his arm to the same height, will bend his body back and forth in accord with his model.
Some acts of imitation, such as yawning, laughing, crying, etc., take place even in the normal condition; generally the idea of a movement determines the action, but in induced sleep the contrary takes place, and the unconscious perception of a movement leads to its accomplishment. This relation explains the facility with which hypnotics are made to execute movements of which what we may call the sensation has been communicated to them in advance. If the subject is not disposed to follow the experimenter when he walks briskly in front of him to excite him, the operator has only to draw him lightly by the hand to make him follow with docility. We have thus explained the secret of the power which the magnetizer exercises over his subject. The former gives an order which the hypnotic does not apprehend, but which he executes nevertheless if he has unconsciously experienced a sensorial impression corresponding with the action which is commanded of him. In testing whether the hypnotic, after waking, remembers what has passed, it is important that he be not assisted by being asked a question the form of which will suggest the answer. If he is asked if he remembers any particular thing, his answer will always be "Yes"; but if he is asked, generally, what has taken place, he will answer that he does not know. The slightest allusion may cause the remembrance to revive; and unconscious traces may be recalled on the intervention of suggestive external excitations. The hypnotic condition, when divested of charlatanism, discloses a multitude of interesting physiological and psychological facts.
In a slight degree of hypnotism, the sensorium commune is still so free that the constraint of involuntary imitation does not exist. As long as consciousness is not obscured, the excitation of the motive apparatus by special sensations does not take place; but when consciousness disappears, the sensorial excitation becomes predominant. So profound states of unconsciousness may be produced that all traces of sensorial perceptions, and the possibility of executing automatic acts of imitation, will disappear. A more advanced symptom of hypnotism is painlessness. Sensibility returns with the cessation of the sleep. The exaggeration of the reflex excitation of the striated muscles is also striking and of surprising duration. A person who has been hypnotized preserves the reflex irritability for whole days and weeks after he has returned to the normal state. When this excitation is light, the contraction is limited to the superficial muscles. In this condition it is easy to induce certain groups of muscles to contract. By passing the finger several times over the fleshy part of the thumb we may cause it to bend toward the palm of the hand; we may cause the head to assume the position known as that of a wry neck by exciting the skin over the sterno-cleido-mastoid muscle with a few light passes.
We may act on more remote muscles by prolonging the excitation. A light rubbing of the inside of the thumb only brings its adductor and flexor muscles into play. A stronger excitation of the same surface brings into action the muscles of the forearm and the flexors of the other fingers, which bend strongly toward the hollow of the hand. The muscles of the elbow and shoulder will be engaged in their turn, and in a short time the upper limb will become motionless. Continuing the passes, we may, in a few seconds, cause the contraction to extend to the left shoulder; the cramp will then descend along the arm, the forearm, and the hand of the left side; the left thigh and leg will yield to the same influence; then the right thigh and leg, the masseters and cranial muscles. It is time to pause. A slight shock on the left arm will cause the contraction to disappear. We can also cause it to cease by quickly opening the fingers of one of the closed hands.
Great prudence is necessary in these experiments lest they be carried too far, and the respiratory muscles be affected. The rigidity of the muscles may be made so great in robust persons that it becomes extremely difficult to change the position of the limbs. They are stiff as a plank, and it is possible to rest an hypnotic by his head and feet alone on two chairs, and carry him around without his body bending.
The first objective sign of the approach of the hypnotic condition is a rigidness of the accommodative apparatus of the eye. The assistants are able to perceive this before the hypnotic can feel it subjectively. The distance to which vision extends diminishes; writing which can be read from a distance can be distinguished only at close sight. Remote points disappear from the field of vision. In a few moments the pupil dilates, and the ball of the eye appears to project. The complexity of these phenomena supposes an excitation of the sympathetic nerve of the neck, which sets in motion the dilator muscle of the pupil and the smooth muscles of the lids and the socket. The initial point of the excitation must then be sought in the spinal marrow, where the sympathetic fibers originate. Other parts of the spinal marrow are not long in being affected, as the respiratory nerves, and the breathing is quickened. The aspirations increase from four to twelve in a quarter of a minute, but the frequency of the pulse is not increased.
Some persons are disposed to hypnotism in consequence of their nervous impressibility, and of the power which imagination exercises over their minds. Others seem to be rebellious against it, and it is necessary to prepare them for it. The contemplation of the glass button exacted by M. Hansen (the magnetizer at Breslau) is intended solely to promote this excitability. Dr. Braid, of Manchester, first demonstrated that the fixed view of inanimate objects provoked a condition akin to the cataleptic sleep. Persons put to this sleep by him became insensible to pain. Some retained a feeling of what passed; others lost it. Fixing the sight upon bright objects is attended by peculiar phenomena. The dazzling effect, the flow of tears, and the fatigue of the retina cause the images on the edges of the field of vision to disappear. The hand that holds the button becomes indistinct and the button fades away. Phenomena of contrasts are produced, and posterior images appear during the involuntary movements of the eyes. Certain feeble and monotonous sounds act in a similar manner to produce stupefaction. If we cause a person to sit with his back against a table on which a watch has been put, and tell him to listen to its ticking, he will in a few minutes fall into the hypnotic sleep, and will then imitate unconsciously the motions of the operator. The effect is especially prompt if the eyes are kept shut. Light and continuous excitations on the surface of the skin exert a similar effect. This is the property on which depend the manipulations of touch and the passes which the magnetizer makes along the face of the person whom he wishes to put to sleep. These passes produce peculiar sensations, partly of contact and partly of heat. The sensations of contact at a distance are produced by the oscillations of the air, which is disturbed by the hand of the magnetizer. These currents occasion an almost imperceptible feeling of prickling, of shuddering. The sensation of heat is provoked by the difference in the temperature of the hand, which has been warmed by exercise, and of the motionless face of the patient.
The reactions to the different excitations vary according to the individual. Some persons are more sensitive to an excitation of the skin; others to that of the hearing or sight. The organs in which stupefaction is first felt are also the first to return to consciousness if they are subjected to an energetic shock. The touch of a cold hand on the face, a word spoken aloud at the ear, a light brought suddenly before the eyes, are enough to break the charm. After the waking, the disposition to hypnotism persists in a latent form. One who has been put to sleep many times has only to imagine he is going to fall into that condition, to go to sleep really. He has only to sit down, shut his eyes, and think, to the exclusion of every other idea, of the torpor which is about to overtake him, for the phenomenon to have its full effect. There is needed, in a word, to produce this effect, an exclusion of all change of thought and images. Having become acquainted with this disposition, we can produce effects which will be really inexplicable to common people. We have only to tell a person who has been recently hypnotized that he will go to sleep at a certain hour, or in a certain place, or while doing a certain thing, for the phenomenon to be produced naturally.
The subject may be made to repeat words spoken before him, by pressing on the nape of his neck. Pressure between the fourth and seventh vertebræ of the neck makes him groan; when applied at the side of the last vertebra, it induces him to draw his leg back; and if made alternately on each side of this vertebra, will cause him to walk backward. Reflex local movements are provoked by the excitation of determinate points of the trunk: raising of the arms over the head, by irritation of the skin of the dorsal region of the pectoral vertebræ turning of the arm backward, by excitation of the skin over the middle vertebræ. If we apply a hearing-trumpet to the nape or the stomach of a hypnotic, he, although he may have been insensible to words pronounced in his ear, will comprehend articulate sounds and repeat them, even though they be in a language that is unknown to him. Hallucinations are produced only if the provoked sleep is light. The hypnotic symptoms may be dissipated by suddenly changing the excitation. If the magnetic state has been produced by passes before the chin, it can be made to disappear by reversing them. The contraction of the arm caused by rubbing the inside of the thumb ceases when the direction of the current is changed. A new sensation dissipates the effect of a previous excitation. It is not, then, a matter of indifference whether we change the direction of the passes: we should persevere in the one which was adopted in the beginning. Rigidity, if it is not intense, ceases on the application of a cold body; a piece of money, a bit of glass, is enough to dispel it. If we touch the forehead or eyes of a hypnotic with a small piece of glass, he will open his eyes and mouth while sleep continues.
It has been asked if we can not obtain semilateral hypnotic phenomena by acting on half the face or head. In fact, by pressing along one side of the forehead or the crown of the head, we may diminish or suspend the influence of the will on the extremities of the opposite side. Light pressures on the left side of the head have produced immobility of the right arm and leg. A shock on the left arm caused this half-paralysis to disappear. The fixed limbs kept indefinitely the position which had been given them, and were found to be in a state of cataleptic suppleness. There appeared at the same time an impossibility to pronounce a word—a condition of ataxic aphasia. Passes on the right side of the head caused the same symptoms, less the aphasia, to appear on the left. Simultaneous passes on both sides of the head developed the cataleptic condition on both sides, aside from the disorder of speech and the facial movements. In all these experiments consciousness was preserved, without the accompaniment of any painful subjective impression. Lateral passes on the skin of the thigh produced singular disorders in certain sensorial impressions. The arm which was made cataleptic did not perceive the difference between a warm and a cold temperature. The eye on the affected side suffered a cramp of the accommodative muscle, and lost at the same time its normal sensitiveness to colors. The hypnotic condition can be explained only by hypothesis. All that is certain about it is, that it is due to a modification of the nervous centers of the brain and spinal marrow.
The apparently voluntary motions of persons in this condition are independent of their will, the sensorial impressions acting directly on their motive apparatus.