Luigi Galvani showed that muscle and nerve cells contained and transported electrical forces that caused muscle contractions, an affect he named “animal electricity.” Galvani demonstrated this by showing that the muscles of dead frog legs twitched when a long metal wire was attached and pointed toward the sky during a thunderstorm.
Prior to Galvani’s discoveries in the 1780s, a leading theory for how muscles moved described the idea that the nerves were tubes that transported fluid and air. This theory was called “balloonist” and went on to describe how the body would move due to expansion of the tubes. Early skepticism of Galvani’s animal electricity theory cast doubt, specifically with an assertion by Alessandro Volta that the wires Galvani used were the cause of the muscles moving. Galvani spent the last years of his life defending his theory, dying in 1798, depressed and in poverty. Galvani was deemed successful in proving his theory conclusively before he died by pressing nerves directly into muscle tissue and recreating the muscle contractions.
Today, Galvani is credited for correctly identifying the role of electricity in humans and laying the foundation for electrophysiology and neuroscience. Galvani correctly theorized the coating around nerves would be nonconductive and that electrical impulses travelled through small holes between the nerves and muscles that were eventually identified and are now called ion channels.