Galvani studied medicine at the university in his native city of Bologna, gaining his MD in 1762 for his thesis on the structure and development of bones. He stayed at Bologna to teach anatomy and in the late 1770s began his experiments in electrophysiology. He observed that the muscles of a dissected frog twitched when touched by a spark from an electric machine or condenser, such as a Leyden jar. Similar responses could be obtained when such muscles were laid out on metal during a thunderstorm, or even by simple contact with two different metals, without the deliberate application of an electric current. Galvani concluded that the source of the electricity therefore lay in the living tissue, and did not derive from outside. His finding was later disproved by Alessandro Volta. However Galvani is celebrated for his discovery of Galvanic electricity (the metallic arc), as well as for applications of his principle to the galvanization of iron and steel and the invention of the galvanometer, named in Galvani's honor by André Ampère. Galvani's animal electricity theory was published as De viribus electricitatis in motu musculari commentarius (1791; Commentary on the Effect of Electricity on Muscular Motion).