It occurred to Galvani that live frogs moved their legs because electricity passed through them. Galvani knew that there was electricity in the air; that it was more noticeable in the amber and glass, but that it was also in the air, and that thunder and lightning came from the electricity in the air.
So he tried to discover whether the dead frogs would not move their legs from the electricity in the air. For this purpose he took the frogs, skinned them, chopped off their heads, and hung them on brass hooks on the roof, beneath an iron gutter. He thought that as soon as there should be a storm, and the air should be filled with electricity, it would pass by the brass rod to the frogs, and they would begin to move.
But the storm passed several times, and the frogs did not move. Galvani was just taking them down, and as he did so a frog’s leg touched the iron gutter, and it jerked. Galvani took down the frogs and made the following experiment: he tied to the brass hook an iron wire, and touched the leg with the wire, and it jerked.
So Galvani decided that the animals lived because there was electricity in them, and that the electricity jumped from the brain to the flesh, and that made the animals move. Nobody had at that time tried this matter and they did not know any better, and so they all believed Galvani. But at that time another learned man, Volta, experimented in his own way, and proved to everybody that Galvani was mistaken. He tried touching the frog differently from what Galvani had done, not with a copper hook with an iron wire, but either with a copper hook and a copper wire, or an iron hook and an iron wire—and the frogs did not move. The frogs moved only when Volta touched them with an iron wire that was connected with a copper wire.