SOME PHYSIOLOGICAL ASPECTS OF HYPNOTISM. 513 



handling of the subject, but it must not be taken as in any 

 sense a definition of volition. 



Sensation or muscular activity in some form are the 

 only certain indications to us of central nervous activ ity. 

 When a specific form of such muscular activity is always 

 obtained in response to a perfectly definite mode of sensory 

 stimulation, then voluntary power is held to be in abeyance; 

 the absence of the power of modifying the muscular re- 

 sponse to specific sensory stimulation thus becomes the 

 important test for determining wliether the animal experi- 

 mented upon has or has not volitional power. However 

 closely an animal's actions resemble those in which volition 

 is an undoubted concomitant, they must, in the absence of 

 such possible modification, be termed automatic. Volitional 

 paralysis thus involves inability to modify the response to 

 definite sensory stimulus, hence such paralysis may result 

 in the display of automatic activity, and this plays a pro- 

 minent part in the production of hypnotic phenomena. 



With this prelude we may proceed to consider quite 

 briefly, some of the chief characters of the phenomena and 

 the means by which they may be produced. 



If a facetted piece of glass, a crystal or some bright 

 object is held a few feet from a person's eyes and slightly 

 above their level, and visual attention concentrate 1 upon 

 the object, then, after a variable time, a change may take 

 place in the gazer. The pupils instead of remaining con- 

 stricted, as they do involuntarily when the eyes are focussed 

 on near objects, gradually dilate. There comes a time 

 when the eyes of the subject no longer change on the 

 approach of the hands of the operator, when the closure of 

 the eyelids by the operator is not followed by an effort to 

 open them, when the subject is thus found to have, to a 

 great extent, lost his voluntary power and to have re- 

 lapsed into a condition which superficially resembles that 

 of sleep. 



This initial sleep of Hypnotism is, however, unlike 

 ordinary sleep, for in the latter the whole nervous system 

 is in a state of subdued activity (thus respiration is slow 

 and shallow), but in the Hypnotic sleep the involuntary 



