363 THE POPULAR SCIENCE MONTHLY 



ARTIFICIAL HYPNOTISM. 



By Dr. R. HEIDENHAIN, 



OF THE PHYSIOLOGICAL INSTITUTE OF BRESLAU. 



THE people of the city of Breslau were, several months ago, greatly- 

 excited over the performances of a professor of animal magnet- 

 ism who seemed to exercise extraordinary power. His subjects were 

 taken indiscriminately from his audiences, and all, even physicians and 

 men of science, who allowed themselves to be experimented upon, yield- 

 ed to his control and contributed to his triumph. Dr. R. Heidenhain, 

 Professor of Physiology and Director of the Physiological Institute of 

 Breslau, on the invitation of the friends of science, delivered a lecture 

 on the subject, in which he undertook to give a physiological explana- 

 tion of the strange effects obtained by the magnetizer, and showed by 

 experiment that the same results could be obtained by the sight or 

 presence of inanimate objects. The following is an abridged transla- 

 tion of this address. [Ed, 



One of the essential symptoms of the hypnotic sleep is the more or 

 less complete loss of consciousness. It is only in a complete state of 

 hypnotism that persons subjected to the experiment preserve a remem- 

 brance of what has passed during their sleep. In some cases the mem- 

 ory is only suspended, and on awaking we may be able to revive the 

 recollection by evoking an association of ideas which will put the sub- 

 ject in train. Sensorial perceptions take place even in the most com- 

 plete hypnotism, but the power of transforming them into conscious 

 representations, and consequently of fixing them in the memory, is ab- 

 sent. Have we not often had experience in the waking state of exter- 

 nal perceptions which did not pass the threshold of consciousness be- 

 cause our attention was absorbed or distracted at the time ? Have we 

 not heard words pronounced around us to which we attached no mean- 

 ing, which were nevertheless perceived by us, if we may speak in that 

 manner, without our knowledge, since we may call them to mind by 

 an effort of memory, provided they have not yet been effaced by a 

 more recent impression ? 



The immediate affection of the senses and conscious perception are 

 distinct physiological conditions, the latter of which supposes a holding 

 of the attention. As the hypnotic's faculty of perceiving a sensation 

 declines, his power of being conscious of it diminishes in a correspond- 

 ing degree. Then, sensorial impressions which do not excite conscious- 

 ness give way to movements which are accomplished almost without 

 our control. A person walking in the street, absorbed in his thoughts, 

 receives the visual impression of the passers-by on his retina without 

 paying attention to them, and unconsciously performs the movements 



