Page:A history of the theories of aether and electricity. Whittacker E.T. (1910).pdf/87

(67) CHAPTER III.

GALVANISM, THOM GALVANI TO OHM.

the last decade of the eighteenth century, electricians were occupied solely with statical electricity. Their attention was then turned in a different direction.

In a work entitled Recherches sur l'origine des sentiments agréables et désagréables, which was published in 1752, Johann Georg Sulzer (b. 1720, d. 1779) had mentioned that, if two pieces of metal, the one of lead and the other of silver, be joined together in such a manner that their edges touch, and if they be placed on the tongue, a taste is perceived "similar to that of vitriol of iron," although neither of these metals applied separately gives any trace of such a taste. "It is not probable," he says, “that this contact of the two metals causes a solution of either of them, liberating particles which might affect the tongue; and we must therefore conclude that the contact sets up a vibration in their particles, which, by affecting the nerves of the tongue, produces the taste in question."

This observation was not suspected to have any connexion with electrical phenomena, and it played no part in the inception of the next discovery, which indeed was suggested by a mere accident.

Luigi Galvani, born at Bologna in 1737, occupied from 1775 onwards a chair of Anatomy in his native city. For many years before the event which made him famons he had been studying the susceptibility of the nerves to irritation; and, having been formerly a pupil of Beccaria, he was also interested in electrical experiments. One day in the latter part of the year 1780 he had, as he tells us, “dissected and prepared a frog, and laid it on a table, on which, at some distance from the frog, was an electric machine. It happened by chance that one of my F 2