While cutting a frog’s leg, Galvani's steel scalpel touched a brass hook that was holding the leg in place. The leg twitched. Galvani believed that he was witnessing the effects of what he called animal electricity—residual life force stuff that lay dormant in the (otherwise) dead-looking leg. Later, his friend Alessandro Volta found that it was the two dissimilar metals (not the frog’s leg) that produced the electricity.

Nonetheless, the link between living motion (in muscles at least) and electrical flow had been established. It would take 60 years before the separate kinds of electricity (static, current, and animal) were shown to be one and the same operating in different contexts.