In 1771 biologist Luigi Galvani, working at the University of Bologna, accidently discovered that frog muscles will twitch when subjected to the electric discharge of a Leiden jar. Ten years later, while dissecting frog muscle suspended on a brass hook with a steel scalpel, he noticed the muscles twitched. Remembering the twitching caused by the electric discharge he incorrectly assumed that the muscle tissue created an electric force when in contact with two different metals. (The "animal electricity" theory.) Alessandro Volta learned of this and performed similar experiments. He replaced the frog tissue with a salt solution and again produced an electric discharge. This soon led to the invention of the first battery or Voltaic pile.