Mary Shelley’s Frankenstein has been scaring readers since 1818. But what inspired the book’s overconfident doctor, who believes he can coax life from death? As Sharon Ruston explains for Public Domain Review, part of Shelley's gothic vision began with a pair of twitching frog legs.

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Ruston writes that Shelley was inspired by the concept of galvanism—the idea that scientists could use electricity to stimulate or restart life. Named after Luigi Galvani, an Italian doctor, the concept came about after Galvani was able to make a frog’s legs twitch when he hooked the animal up to an electric charge.

Electricity was a new and barely understood force when Galvani performed his experiments on dissected animals during the late 18th century, so it makes sense that people thought it might just be able to make creatures come alive after death. Ruston notes that Galvani’s nephew, Giovanni Aldini, went so far as to shock dissected human corpses in pursuit of this hypothesis.

In Frankenstein, Shelley only mentions the word “galvanism” once in a passage where the hubristic Dr. Frankenstein describes how a lecture on electricity caused him to throw away everything he knew about science. “All that had so long engaged my attention grew suddenly despicable,” says Frankenstein. “…I at once gave up my former occupations, set down natural history and all its progeny as a deformed and abortive creation, and entertained the greatest disdain for a would-be science which could never even step within the threshold of real knowledge.”

In the 1831 preface to Frankenstein, however, Ruston points out that Shelley directly acknowledges galvanism as part of the inspiration for her novel, writing of her discussions with Lord Byron, "Perhaps a corpse would be re-animated; galvanism had given token of such things: perhaps the component parts of a creature might be manufactured, brought together, and endued with vital warmth."

These days, of course, it’s galvanism that is denied as real knowledge. While the branch of science known as electrophysiology does examine how cells and tissues use electricity, the idea that a simple charge can bring life to what’s dead seems as dated as Shelley’s original manuscript. Yet the book that was inspired by a few twitching frog legs still lives on, nearly 200 years after it was first published.