There’s no shortage of melodramatic moments in Guillermo del Toro’s new Frankenstein adaptation.

But nowhere does del Toro’s cavernously emotional take on Mary Shelley’s classic novel crackle with dark energy more than it does on the fateful night in Victor Frankenstein’s laboratory when, in the midst of a nightmarish electrical storm, the creature he’s cobbled together from discarded limbs is brought to life.

It is, of course, a scene that most viewers will find at least passingly familiar. Because if there is one image that Shelley’s Frankenstein, and countless adaptations and derivative works since, has planted firmly in the public consciousness, it is that of an unsavory pile of meat getting jolted to life.

But what is less well appreciated is that this unholy awakening was inspired by real scientific experiments of the 18th and 19th centuries that attempted to elucidate the connection between electricity and life.

To some, humans appeared on the cusp of being able to create life using little more than a spark. It was an idea that raised difficult ethical questions that remain relevant in an age of genetic engineering and machine intelligence. But at the time, the morality of electricity science was less of a concern than the threat this knowledge posed to Britain’s religious and political elites.

“The Church of England is one of the pillars of the early 19th-century state,” Iwan Morus, an expert on Victorian era science at Aberystwyth University in Wales, told The Science of Fiction. “If you can generate life by means of electricity, then there’s no soul. If there’s no soul, there’s no God. If there’s no God, what’s the Church doing?”

Early on in the history of electrical experimentation, natural philosophers — the forerunners of modern scientists — grew interested in the relationship between electricity and life. Isaac Newton speculated about a potential connection between the two in the early 18th century. In the 1830s, the experimenter Stephen Gray ran a public demonstration called “The Flying Boy,” in which he suspended a boy from a ceiling on silk cords, rubbed his feet with a glass rod or globe to transfer a charge to them, and mesmerized audiences by showing how the boy’s hands attracted objects such as a gold leaf. 

By the mid-18th century, another experimenter, Jean Antoine Nollet, was entertaining the French king by lining up a row of guardsmen in front of an electrical machine called a Leyden jar. When one of the soldiers touched the machine, the guardsmen, who were holding hands to create a circuit, were all jolted upwards at once. 

These early demonstrations, Morus says, were intended to be subversive. “We have experiments being carried out in front of an absolutist monarch showing how people can be treated as puppets,” he says. “The political connection was there very early on.”

But the truly radical experiments—those suggesting that electricity could not just affect life, but bring back the dead—were still to come.

In the late 18th century, Italian physician Luigi Galvani witnessed a frog leg twitch after an exposed nerve was touched with metal.

He went on to spend years studying how electricity can cause muscular spasms. Ultimately, Galvani concluded that there is innate electricity inside bodies, and that this “animal electricity” is the spark of life itself.

In 1803, shortly after Galvani died, his nephew Giovanni Aldini performed a shocking demonstration of his uncle’s ideas. After receiving the body of George Foster, a man recently hanged for murder, Aldini attempted to reanimate the corpse in front of London’s Royal College of Surgeons. As Aldini flooded the body with electricity, Foster’s corpse raised its hand and moved its legs. It was scandalous—and sensational.

“You get these very, very lurid accounts of the corpse twitching, the corpse moving,” Morus said. “Lots of satire about how silly these philosophers are imagining they can recreate life. And that’s the context of Frankenstein.”

Mary Shelley (née Godwin) was a small child when Aldini’s spectacle took place. But Morus says that as a member of the English intelligentsia—her father was a political philosopher; her mother a prominent women's rights advocate—she would have been “perfectly familiar” with these sorts of experiments when she wrote the novel beginning in the summer of 1816. 

“It’s part of fashionable, political, literary culture during this period,” Morus said.

Morus noted that Percy Shelley, whom Mary Shelley married in 1816, conducted his own electrical experiments while he was at school, and that William Lawrence, the Shelley family doctor, was engaged in a “vitriolic debate” with the English surgeon John Abernathy over the nature of life. Abernathy, Morus said, believed that something like electricity was needed to animate matter; Lawrence, a materialist, insisted that life is simply an organization of matter and that no additional spark is required.

Mary Shelley’s own view on the matter is unknown. But Frankenstein, first published in 1818, ponders these exact issues—the nature of life, the existence of the soul, and what it might mean to live without one. “That’s the conundrum of the creature,” Morus said. “The creature has been brought to life, but what exactly does that life entail? Does it have a soul? Is it spiritual? It’s a question readers are being invited to think about.”

It’s not a question the political and religious elites of Shelley’s world welcomed.

The ideas espoused in Frankenstein—and by others interested in the connection between electricity and life—were “distinctly heterodox and dangerous,” Morus said. “This is attacking the fabric of civilized, decent life.”

But while many readers found Frankenstein shocking, and literary critics described it using terms like “horrible” and “disgusting,” the book was widely read. By 1823, the first Frankenstein play was being performed at the English Opera House in London. Successive editions of the book were published, along with more theatrical adaptations. 

Our fascination with Frankenstein has never faded.

Shelley’s novel has seen dozens of film adaptations since the early 20th century, including not just horror flicks but comedies like Mel Brooks and Gene Wilder’s Young Frankenstein and even a musical parody, The Rocky Horror Picture Show. Frankenstein’s creature has appeared in countless comic books and video games. Few horror fiction icons rival his celebrity.

The popularity of Del Toro’s latest adaptation is a testament not just to his brilliance as a filmmaker and Shelley’s masterful storytelling, but to the continued relevance of the questions at the heart of Frankenstein. As we continue bringing new forms of life into the world—whether that’s genetically engineered crops, babies whose genomes have been modified with CRISPR, or perhaps one day soon, sentient machines—our morality and responsibility, as the creators, remain on trial.

“The 19th century started thinking of technology as a way of transforming the world completely,” Morus said. “That’s the world we still inhabit. And ethically, if that’s the world we inhabit, then we’re obliged by being human to think about what that does to us; to the people around us. What does that do to the world? And Shelley was one of the first to pose that question — at the beginning of the process.”