Page:Encyclopædia Britannica, Ninth Edition, v. 15.djvu/300

Rh 282 MAGNETISM [ANIMAL MAGNETISM, 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 is 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 vsensory 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 imme diately 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) : &quot; 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 muscles 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 &quot;stiff neck&quot;; stroking the skin at one corner of the mouth leads to distortion of the mouth 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 denned 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 aud stretch his arm at the elbow, the upper arm muscles 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.&quot; 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 Griitzner (Breslaiier 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. &quot;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 meairs of Mosso s 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&quot; (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, 3 ellow is seen, as it were, through a blue mist ; fourth stage, yellow appears mostly yellow, with a 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 &quot; (Heiden hain, 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 ac counted 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 amuse ment. 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