PROTECTIVE MECHANISMS OF THE NERVOUS SYSTEM 725 



be subjected to most unusual conditions. Quite similarly, it is pos- 

 sible to influence his mental concepts in such a way that memories 

 of certain past experiences are lost, while others are artificially created, 

 thereby changing the entire character of the person. He may assume 

 the character of a typical paralytic, bUnd or deaf person. Some of 

 these suggestions may even produce posthypnotic results many days 

 and weeks after the hypnosis. Thus, when a postage stamp was placed 

 upon the skin of a hypnotic and it was suggested to him that it would 

 raise a blister, such a formation was actually found beneath it on the 

 following day. Subcutaneous hemorrhages may be induced in the 

 same way, and so may ''brand-marks" by simply suggesting to the 

 hypnotic that, say, a piece of chalk used upon the skin, is a red hot 

 iron. 



Hypnotic states may also be evoked in animals. Thus, it is not 

 difficult to render frogs, birds and rabbits motionless by a continued 

 gentle pressure upon the dorsal aspect of their body, such as may be 

 produced by holding them in the palm of the hand. A lobster may in 

 this way be made to stand upon its head supported only by the first 

 pair of appendages. Kircher's experimentum mirabile (1644) con- 

 sists in rendering a fowl temporarily quiescent by placing a straw across 

 its bill or by fixing its head in such a way that the eyes look directly 

 at a chalk line drawn across the table. Verworn,i however, states 

 that this is not an instance of true hypnosis but solely one of optical 

 inhibition of reflexes. 



Narcosis. — Omitting the largely speculative theories regarding 

 the causation of narcosis, it has always been supposed that the nar- 

 cotics enter into a chemical combination with the constituents of the 

 protoplasm. In analogy to this union might be mentioned the action 

 of curarin upon the motor nerve-endings or that of carbon monoxid upon 

 the hemoglobin. Peculiarly enough, certain narcotics of the aliphatic 

 series are chemically inactive, although capable of inducing a character- 

 istic narcotic action. It was subsequently found that all possess the 

 property of being dissolved in water and fats, this property being 

 responsible for their absorption and distribution to the cells of the 

 body. Bibra and Harless,^ therefore, conceived the idea that the action 

 of the anesthetics is dependent upon their power of dissolving fat. This 

 hypothesis, however, seems untenable, because it fails to explain the 

 rapid restitution of function following the anesthetization. In other 

 words, *it seems unlikely that the fat dissolved out of the nervous tissue 

 to institute narcosis, can again be replenished in so short a time. 



While no definite theory of narcosis has been formed to supplant 

 the preceding, some interesting data have been gathered which partly 

 explain the anesthesia. Thus, it has been shown by Meyer^ and 



1 Die sogenannte Hypnose der Tiere, Jena, 1898. 



2 "Qber die Wirkung des Schwefelathers, 1847. 



3 Archiv fiir Exp. Path, und Pharm., vi, 1901, 12. 



