HYPNOTISM. Ill 



notic condition may be induced in susceptible persons by a feeble, 

 continued, and regular stimulation of the nerves of touch, sight, or 

 hearing ; and may be terminated by a strong or sudden change in the 

 stimulation of these same nerves. 



The physiological explanation of the hypnotic state which Heiden- 

 hain ventures to suggest is, that a stimulus of the kind just mentioned 

 has the effect of inhibiting the functions of the cerebral hemispheres, 

 in a manner analogous to that which is known to occur in several other 

 cases which he quotes of ganglionic action being inhibited by certain 

 kinds of stimuli operating upon their sensory nerves. 



In a more recent paper, embodying the results of a further investi- 

 gation in which he was joined by P. Grutzner, Heidenhain gives us 

 the following supplementary information : 



The muscles which are earliest affected are those of the eyelids ; 

 the patient is unable to open his closed eyes by any effort of his will. 

 Next, the affection extends in a similar manner to the muscles of the 

 jaw, then to the arms, trunk, and legs. But even when so many of 

 the muscles of the body have passed beyond the control of the will, 

 consciousness may remain intact. In other cases, however, the hyp- 

 notic sleep comes on earlier. 



Imitative movements become more and more certain the more they 

 are practiced, so that at last they may be invariable and wonderfully 

 precise, extending to the least striking or conspicuous of the changes 

 of attitude and general movements of the operator. Professor Berger 

 observed that, when pressure is exerted with the hand at the nape of 

 the neck upon the spinous process of the seventh cervical vertebra, the 

 patient will begin to imitate spoken words. It is immaterial whether 

 or not the words make sense, or whether they belong to a known or 

 to an unknown language. The tone in which the imitation is made 

 varies greatly in different individuals, but for the same individual is 

 always constant. In one case it was a hollow tone, " like a voice from 

 the grave " ; in another almost a whisper, and so on. In all cases, how- 

 ever, the tone is continued in one kind, i. e., it is monotonous. Further 

 experiments showed that pressure on the nape of the neck was not the 

 only means whereby imitative speaking could be induced, but that the 

 latter would follow with equal certainty and precision if the experi- 

 menter spoke against the nape of the neck especially if he directed 

 his words upon it by means of a sound-funnel. A similar result fol- 

 lowed if the words were directed against the pit of the stomach. It 

 followed with less certainty when the words were directed against the 

 larynx or into the open mouth, and the patient remained quite dumb 

 when the words were directed into his ear, or upon any other part of 

 his head. If a tuning-fork were substituted for the voice, the note of 

 the fork would be imitated by the patient when the end of the fork 

 was placed on any of the situations just mentioned as sensitive. By 

 exploring the pit of the stomach with a tuning-fork, the sensitive area 



