12 HISTORY OF 



action, and the possibility of applying this agent to the relief of 

 disease. The physiological effects of Galvanism, which almost 

 exclusively occupied the attention of philosophers previous to 

 the discovery of the pile, were those in which contractions in 

 the muscular parts of animals were exhibited. The source of 

 that surprising power which called forth such sudden and 

 forcible muscular contractions, as took place when the nerve 

 and muscles of the limb of a frog were respectively in contact 

 with different metals which were themselves made to communi- 

 cate, either directly or by the intervention of other metals, was 

 most anxiously sought after ; and it was not till after a long 

 period of laborious research, in which a prodigious number of 

 experimentalists in every part of Europe engaged, and occa- 

 sionally involved themselves in inextricable mazes of perplexity, 

 that the identity of the Galvanic and the Electric agencies 

 was recognized and finally established. The ardour and per- 

 severance with which these experiments were carried on, may 

 be gathered from the fact that many of the philosophers 

 subjected themselves to no inconsiderable suffering for the 

 purpose of thoroughly carrying out the enquiry. Humboldt, 

 for example, informs us that, with a view of more precisely 

 ascertaining the nature of the contractions produced by different 

 metals, he purposely applied two blisters over the deltoid 

 muscles in his own arms; he covered one of the wounds with 

 a large silver medal, and the other with a plate of zinc, and 

 by means of a zinc wire established a communication between 

 the two metals : the result of the contact was not only a 

 violent smarting sensation on the blistered surfaces, but an 

 alternate contraction of the muscles of the shoulder and the 

 neck. When the blistered surfaces had been exposed to the 

 air for the space of half an hour, so as to have become covered 

 with effused lymph, the effect of the Galvanic contact was 

 much diminished; but when, under these circumstances, a 

 few drops of an alkaline solution were poured on the coating 

 of lymph, the sensibility was immediately restored, the pain 

 became extremely violent, and the contractions were renewed 

 and succeeded each other several times successively. Not 



