764 THE POPULAR SCIENCE MONTHLY. 



matic movements, and to experience hallucinations and illusions 

 of the senses. A solution of quinine is drunk with every show of 

 satisfaction if the operator merely states with sufficient emphasis 

 that it is a delicious cup of chocolate. 



The fifth degree of hypnotism is known as light somnam- 

 bulism. In deep somnambulism (sixth degree) the subject has no 

 memory whatever of what has passed during the sleep. There is 

 absolute amnesia. Nevertheless he can hear and obey suggestions 

 with great readiness. There are cases of deep somnambulism, 

 however, in which there is scarcely any suggestibility, and in 

 which all the senses appear to be in temporary abeyance. 



The above description of the various grades of hypnotism is 

 far from satisfactory, for every person preserves in some degree 

 his own individual peculiarities and impresses them upon the 

 hypnotic state, and this gives rise to an almost infinite number 

 of varieties which overlap one another in every imaginable 

 way. 



The proportion of somnambulists to the total number of per- 

 sons who can be hypnotized is large, being about nineteen per 

 cent in adults. Sex seems to be an unimportant factor, contrary 

 to what was formerly supposed, for the preponderance in favor of 

 women is only about one per cent. The j)roportion of somnam- 

 bulists among children is much higher, being about twenty-six 

 per cent in children from one to seven years of age. More than 

 half the children betAveen the eighth and fourteenth year are 

 somnambulists. 



I have heretofore only spoken of the phenomena which are 

 present during the actual sleeping state of the hypnotized sub- 

 ject. In addition to these, there is a class of manifestations which 

 make their appearance after the subject has awakened. These 

 post-hypnotic phenomena, as they are called, are the result of sug- 

 gestion, and can only be produced in somnambulists. The mani- 

 festations themselves only differ from those of somnambulism in 

 that they persist, or only take effect, after the subject awakes. 

 Thus, we can suggest post-hypnotic acts, illusions of the various 

 senses, and hallucinations. For example, a good somnambulist is 

 hypnotized and told that on awaking he will commit a certain 

 act, that he must commit it, and can not offer any resistance to his 

 desire to commit it. Accordingly, when he awakes he executes 

 the suggestion which has been insinuated into his mind, either 

 literally or with some slight modification, and, not having any 

 recollection of what has been told him, believes that his act is 

 spontaneous. These cases afford the best illustration I know of 

 the relativity of our freedom of will, and of the truth of Spinoza's 

 saying, that our consciousness of free-will is but ignorance of the 

 causes of our acts. If the act which has been suggested is one 



