1 20 Traces of Unity in 



covered, among other things, that a galvanoscopic frog 

 would contract without the help of a conducting arc 

 composed of heterogeneous metals. He discovered, not 

 only that these contractions would happen when this 

 arc was composed of a single metal, but also that an 

 arc composed of muscle or nerve would answer the 

 same purpose as the metallic arc. He also discovered 

 that the limb of a galvanoscopic frog, of which the 

 nerve had been divided high up in the loins, would con- 

 tract at the moment when the end of the nerve below 

 the line of section was brought down and .made to 

 touch a part of the trunk of the same nerve. At last, 

 indeed, he hit upon an experiment in which he seemed 

 to have to do with an electricity other than that arising 

 from the reaction of heterogeneous bodies an elec- 

 tricity which must belong to the animal tissues them- 

 selves. He did much, but he did not do enough to. win 

 the battle in which he was engaged, for Volta still kept 

 his position, denying the existence of animal electricity, 

 and maintaining that the electricity which produced the 

 contractions in the galvanoscopic frog was always due 

 to electricity arising in the reaction of heterogeneous 

 bodies of one kind or other silver and copper, metal 

 and organic tissue, muscle and nerve, nerve in one state 

 with nerve in another,, as the case might be.* 



In 1799, Humboldt took up the question at issue 

 between Galvani and Volta, and published a workf in 

 which he shows by many new and curious experiments 

 that there was error, on both sides that Volta was 

 wrong in ignoring altogether the influence of .animal 

 electricity in Galvani's experiments, and that Galvani 

 was not less wrong in recognising nothing but this in- 



* "Ann. de Chim.," T. xxiii, pp. 276 and 301. 

 f- Op. cit. 



