io8 THE POPULAR SCIENCE MONTHLY. 



HYPNOTISM.* 



By G. J. ROMANES. 



CONSIDERING the length of time that so-called " animal magnet- 

 ism," " mesmerism," or " electro-biology," has been before the 

 world, it is a matter of surprise that so inviting a field of physiological 

 inquiry should have been so long allowed to lie fallow. A few scientific 

 men in France and Germany have indeed, from time to time, made a 

 few observations on what Preyer has called the " Kataplectic state " as 

 artificially induced in human beings and sundry species of animals ; 

 but anything resembling a systematic investigation of the remarkable 

 facts of mesmerism has not hitherto been attempted by any physiolo- 

 gist in our generation. The scientific world will therefore give a more 

 than usually hearty welcome to a treatise which has just been published 

 upon the subject by a man so eminent as Heidenhain. The research of 

 which this treatise is the outcome is in every way worthy of its dis- 

 tinguished author ; for it serves not only to present a considerable and 

 systematic body of carefully observed facts, but also to lead the way 

 for an indefinite amount of further inquiry along the lines that it has 

 opened up. 



Heidenhain conducted his investigations on medical men and stu- 

 dents as his subjects, one of them being his brother. He found that, 

 in the first or least profound stage of hypnotism, the patient, on being 

 awakened, can remember all that happened during the state of mes- 

 meric sleep ; on awakening from the second or more profound stage, 

 the patient can only partially recollect what has happened ; while in 

 the third, or most profound stage, all power of subsequent recollection 

 is lost. But, during even the most profound stage, the power of sen- 

 sory perception remains. The condition of the patient is then the 

 same, so far as the reception of sensory impressions is concerned, as 

 that of a man whose attention is absorbed or distracted ; he sees 

 sights, hears sounds, etc., without knowing that he sees or hears them, 

 and he can not afterward recollect the impressions that were made. 

 But the less profound stages of hypnotism are paralleled by those less 

 profound conditions of reverie in which a passing sight or sound, 

 although not noticed at the time, may be subsequently recalled by an 

 effort of the will. Further on in his treatise Heidenhain tells us that, 

 even when all memory of what has passed during the hypnotic state is 

 absent on awakening, it may be aroused by giving the patient a clew, 

 just as in the case of a forgotten dream. This clew may consist only 



" * Dor sogenannte thierische Magnetismus." Physiologische Beobachtungen, von Dr. 

 Rudolf Heidenhain, ord. Professor der Physiologic und Director der physiologischcn In- 

 stitutes zu Breslau. (Breitkopf und Hartel, Lcipsic, 1880.) 



