Page:Popular Science Monthly Volume 18.djvu/122

112 was found to begin about an inch below the breastbone, and from thence to extend for about two inches downward and about the same distance right and left from the middle line, while the navel, breastbone, ribs, etc., were quite insensitive. Heidenhain seeks—though not, we think, very successfully—to explain this curious distribution of areas sensitive to sound, by considerations as to the distribution of the vagus nerve.

Next we have a chapter on the subjection of the intellectual faculties to the will of the operator which is manifested by persons when in a state of hypnotism. For the manifestation of these phenomena the sleep must be less profound than that which is required for producing imitative movements; in this stage of hypnotism the experimenter has not only the motor mechanism on which to operate, but likewise the imagination. "Artificial hallucinations" may be produced to any extent by rehearsing to the patient the scenes or events which it may be desired to make him imagine. A number of interesting details of particular cases are given, but we have only space to repeat one of the most curious. A medical student, when hypnotized in the morning, had a long and consecutive dream, in which he imagined that he had gone to the Zoölogical Gardens, that a lion had broken loose, that he was greatly terrified, etc. On the evening of the same day he was again hypnotized, and again had exactly the same dream. Lastly, at night, while sleeping normally, the dream was a third time repeated.

A number of experiments proved that stimulation of certain parts of the skin of hypnotized persons is followed by certain reflex movements. For instance, when the skin of the neck between the fourth and seventh cervical vertebræ is gently stroked with the finger, the patient emits a peculiar sighing sound. The similarity of these reflex movements to those which occur in the well-known "croak-experiment" of Goltz is pointed out.

A number of other experiments proved that unilateral hypnotism might be induced by gently and repeatedly stroking one side or other of the head and forehead. The resulting hypnotism manifested itself on the side opposite to that which was stroked, and affected both the face and limbs. When the left side of the head was stroked, there further resulted all the phenomena of aphasia, which was not the case when the right side of the head was stroked. When both sides of the head were stroked, all the limbs were rendered cataleptic, but aphasia did not result. On placing the arms in Mosso's apparatus for measuring the volume of blood, it was found that, when one arm was hypnotized by the unilateral method, its volume of blood was much diminished, while that of the other arm was increased, and that the balance was restored as soon as the cataleptic condition passed off. In these experiments consciousness remained unaffected, and there were no disagreeable sensations experienced by the patient. In some instances,