410 THE POPULAR SCIENCE MONTHLY. 



Various stories are told of the manner in which Galvani's dis- 

 covery of galvanic action, or " animal electricity," as he called it, 

 was brought about. According to one version, he was preparing 

 a frog-broth for his invalid wife, and some skinned frogs were 

 lying on a table by the side of an electrical machine. One of his 

 assistants accidentally touched the crural nerve of one of the 

 frogs with the point of a scalpel, when all the muscles of the 

 limbs seemed to be taken with strong spasms. Madame Galvani, 

 a bright, thoughtful woman, who was present and witnessed the 

 shock, was struck with the novelty of the phenomenon, and thought 

 that she noticed along with it a disengagement of the electric 

 spark. She informed her husband at once, and he lost no time in 

 verifying the extraordinary fact. The point of the scalpel being 

 again applied to the frog, while a spark was drawn from the ma- 

 chine, the contractions were resumed. To determine whether they 

 were not due to the simple contact of the scalpel, Galvani touched 

 the same nerves of other frogs without turning the machine, and 

 got no contractions. Repetitions of the experiments were accom- 

 panied with corresponding results. Another account makes Gal- 

 vani himself the chief actor in the incident ; while, according to 

 a third account, Galvani, having dissected some frogs, in a study 

 of their nervous system, hung them on an iron railing with a 

 copper hook thrust in their lumbar nerves, and the contractions 

 took place whenever, in the vibration of the specimens, these 

 nerves touched the iron too. According to the documents in the 

 possession of the Museum of Bologna, the discovery was not all 

 a matter of accident, as these stories would make it appear, for it 

 is shown there that Galvani had been engaged, for twenty years 

 before the publication of his Commentary, in investigations of 

 the action of electricity on the muscles of frogs. The thought in- 

 volved in these experiments had also been more or less vaguely 

 suggested by other writers. Sulzer, in his Nouvelle Thdorie du 

 Plaisir, published in 1767, had spoken of the peculiar taste pro- 

 duced when two pieces of different metals were put, under certain 

 precautions, into the mouth. A pupil of Cotugno, Professor of 

 Medicine at Naples, in dissecting a mouse about 1786, perceived a 

 movement at the moment when his scalpel touched one of the 

 animal's nerves. Galvani described his experiments, and claimed 

 that he had discovered a kind of electricity having remarkable 

 peculiarities, in the Commentary (De Viribus Electricitatis in 

 Motu Musculari) already mentioned, which was published in 

 1791 and 1792. One of the immediate results of his discovery 

 was the invention of his metallic arc, the first experiment with 

 which is described in the third part of the Commentary, with 

 the date September 20, 1786. This arc was constructed of two 

 different metals, which, placed in contact, one with a nerve and 



