l6 GALVANIC ELECTRICITY. 



/inc be placed on the upper surface of the tongue, and both mefals 

 after a short space of time be brought into contact, a peculiar 

 sensation, or taste, will be perceived at the moment when the 

 mutual touch happens. If the silver be put beneath, and the zinc 

 upon the tongue, the same sensation will arise, but in a weaker de- 

 gree, resembling diluted ammoniac, from which it in all probability 

 derives its origin. 



If a silver probe be introduced as far as convenient into one of 

 the nostrils, and then be brought into contact with a piece of zinc 

 pinned on the tongue, a sensation not onlike a strong flash of light 

 will be produced in the corresponding eye, at the instant of contact. 

 A similar perception will result, both at the moment of contact 

 and that of separation, if one of the metals be applied as high as 

 possible between the gums and upper lip, and the other in a similar 

 situation with the under lip, or even under the tongue. Lastly, 

 when a probe or rod of zinc, and another of silver, are introduced 

 as far back as possible into the roof of the mouth, the irritations 

 produced by bringing the external ends into contact, are very power, 

 ful ; and that caused by the zinc is similar in taste to the sensation 

 arising from its application to the tongue. 



No method has hitherto been discovered of applying the galvanic 

 influence in such a manner as to affect the senses of smell, hearing, 

 and touch ; though several eminent philosophers have carefully in. 

 vestigated the subject. Nor are the causes of these phacJiomena 

 clearly ascertained ; Galvani and many of his followers supposing 

 them to depend on ihe electric fluid, while others attribute them to 

 the influence of various physical agents. 



^JWr. Crceve, surgeon in Wurtzburg, had an opportunity of ob- 

 ( serving the irritation on the leg of a boy, which had been amputated 

 \ far above tie knee in the hospital of that city. Immediately after 

 / the amputation, Mr. Creeve laid bare the crural nerve (kiekehlner- 

 \ ven), and surrounded it with a slip of tinfoil. He touched at once 

 the tinfoil and the nerve with a French crown-piece. In that infant 

 the most violent convulsions took place in the leg both above and 

 below the knee. The remainder of the thigh bone bent with force 

 toward the calf; the foot was more bent than extended. All these 

 motions were made with much force and rapidity. None were pro, 

 duced when the tinfoil was taken away, or when a steel pincer was 

 used in place of a piece of silver, or when the tin or silver was co- 

 vered with blood ; but they were renewed when these obstacle* 



