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Page:Popular Science Monthly Volume 18.djvu/378

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THE POPULAR SCIENCE MONTHLY.

tized 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