�The Galvanic Apparatus�, 1804.

UNITED KINGDOM - SEPTEMBER 04: Engraving by J Pass after Henry Lascelles, showing apparatus for demonstrating �animal electricity� as discovered by Luigi Galvani (1737-1798). Whilst investigating the effects of electrostatic stimuli applied to the muscles of frogs, Galvani discovered he could make a muscle twitch by touching the nerve with metal without a source of electrostatic charge. This showed that nerves and muscles in animals function by tiny electrical currents, and can be stimulated by the application of metal or electricity from outside. A pair of frog�s legs is seen here at top right. The term 'galvanise' - to shock or excite into action - takes its name from Galvani. Illustration from �Encyclopaedia Londinensis, or, Universal Dictionary of Arts, Sciences, and Literature� published in London, 1810-1829. (Photo by SSPL/Getty Images)