One night in the late 1700s, Luigi Galvani, an anatomy professor at the University of Bologna, strung up butchered frog legs on his balcony. This in itself was not unusual – they were, in all likelihood, awaiting the dinner plate. But on this night, with the air crackling with electricity from a storm, Galvani noticed something odd: when he touched the legs with a pair of scissors, they twitched. The professor’s curiosity was piqued. Soon thereafter, he hung some dissected frogs legs in his laboratory – where, as it happened, he also kept a newfangled machine that captured static electricity, known as a Leyden jar. Anytime the jar was on and someone touched the legs with a metal scalpel, they jumped. It was almost as if they were possessed.
Galvani wondered if this strange phenomenon could be related to electrical currents. Perhaps the limbs contained some sort of charge, an “animal electricity” essential for life. He thought that this charge was undiscovered biological juice, and, while he was wrong, Galvani was perhaps the first person to purposefully stimulate exposed nerve cells with electricity. Years later, he noted his achievement in a book that recounted more than a decade of such research: “And still we could never suppose that fortune were to be so friend to us, such as to allow us to be perhaps the first in handling, as it were, the electricity concealed in nerves, in extracting it from nerves, and, in some way, in putting it under everyone’s eyes.”
In the years that followed, Giovanni Aldini, Galvani’s nephew and former assistant, went further. In 1802, he connected a primitive battery to a recently severed ox head. It was as if the animal came back to life: its eyes flew open; its ears wriggled; its tongue jerked. Aldini attempted a similar experiment on the corpse of a murderer who’d been hanged in London’s infamous Newgate Prison. The effects were much the same: “The jaw began to quiver, the adjoining muscles were horrible contorted, and the left eye actually opened.”