twitching frog legs experiment

How Twitching Frog Legs Helped Inspire ‘Frankenstein’

Galvanism sought to reanimate the dead—and in doing so provided the impetus for one of literature’s most famously frightful books

Erin Blakemore

Correspondent

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.

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.

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Erin Blakemore | | READ MORE

Erin Blakemore is a Boulder, Colorado-based journalist. Her work has appeared in publications like The Washington Post , TIME , mental_floss , Popular Science and JSTOR Daily . Learn more at erinblakemore.com .

CONNECTING SCIENCE TO YOU

THE EXPERIMENT THAT SHOCKED THE WORLD

By: Andrew Lai

A Galvanized corpse. Published in 1836, this cartoon depicts Galvani’s nephew electrifying a criminal’s corpse.

Established pillars were under attack across the Western world. It was the late 1700s, and the United States had just declared independence. France was rapidly heading towards a bloody revolution. Industrialization was beginning to reshape society. And, amidst the chaos, an obscure Italian physiologist stepped outside to do a science experiment.

In his back garden, all of his equipment lay ready. The lightning rod was installed. A frog corpse lay on the table. A storm was coming. All that remained was the final touch: connecting the lightning rod to the frog. Then, after making the connection, it was time to wait.

At long last, the storm came. Whenever lightning flashed nearby, energy coursed down the rod and the frog’s leg twitched!

The scientist, Luigi Galvani, must have been ecstatic. Over the past several years, he had come to believe that electricity was linked to movement. He had already shown that his static electricity generator made frog legs twitch in controlled laboratory conditions. Here was a piece of evidence to improve his theory: a connection between naturally occurring electricity and movement. In those moments, Galvani must have felt like he was on to something. Maybe this was the key to movement, the key to life!

Figure 1. T he original print from Galvani’s 1791 publication . An illustration of Galvani’s setup, depicting a dead frog connected to a lightning rod.

In the years that followed, the lightning experiment became a piece of Galvani’s magnum opus: the theory that animals generate electricity – and they use this intrinsic electricity to make their body move. This theory of “animal electricity” sent shockwaves throughout the scientific community, medical community, and the communities of everyday people.

The first reverberations hit the community of scientists studying movement. Up until Galvani’s time, the field of movement studies was a chaotic scientific wilderness. In the 18th century, scientists held many different beliefs regarding the impetus that caused muscles to contract, many of them mystical in nature. Many scientists and doctors still believed in a theory harking back to the Ancient Greeks. They believed the body was governed by pneuma, a psychic fluid that was said to control all movements.

As a result, the scientific climate was replete with superstition and tribal alliances. As one member of the Royal Society of London observed (a mere three years before Galvani published his results), “ No argument from fact has been employed to prove any [theory of muscular movements]: I shall therefore leave them as mere chimeras of the brain ” (emphasis mine).

Galvani’s theory provided the “argument from fact” that was so badly needed. With animal electricity theory, scientists were able to verify their scientific hypotheses using electrical equipment. Armed with this new way to think about movement, the study of human physiology became increasingly grounded in physics, and less grounded in mystical beliefs. And, if only a little bit, movement scientists pushed the scientific frontier further into the distance.

Galvani’s work also sent shockwaves far beyond the small community of muscle movement scientists. The ripples of animal electricity were felt by many, but the theory was most transformative in the life of Allenssandro Volta. At the time, Volta was a Professor of Physics in Pavia, Italy. After reading Galvani’s work, Volta felt so inspired that he performed his own animal electricity experiments. But, Volta gradually became concerned that one of Galvani’s experiments had led to a false conclusion.

In the disputed experiment, Galvani had connected a frog’s leg to its spinal cord using two different pieces of metal (these metals were usually iron and bronze or iron and silver). Upon touching the metals to complete the circuit, the frog’s leg twitched. Galvani concluded that electricity was intrinsic to the frog and the metals simply acted as a conduit.

Figure 2. This animated figure shows Galvani’s understanding of animal electricity. When the bronze (yellow wire) is connected to iron (silver wire), charges flow between the frog’s positively-charged outside and the frog’s negatively-charged inside. This circuit completion causes the frog’s muscles to contract. (Figure credit: Andrew Lai)

But Volta identified a flaw in Galvani’s logic. What if the mere connection of two different metals could create electrical current? Volta set to work, trying many different combinations of metals. Silver touching copper? Electrical current. Iron touching zinc? Electrical current. With this evidence, Volta argued that the two metals created an electrical current; thus, the metals alone were responsible for the twitches. Bi-metal electricity left no room for intrinsic animal electricity.

Figure 3. This animated figure shows Volta’s understanding of animal electricity. When the bronze (yellow wire) is connected to iron (silver wire), the two metals create electrical current. This causes the frog’s muscles to contract. (Figure credit: Andrew Lai)

The ensuing debate over animal electricity led Volta to publish his theory of bi-metal electricity in 1800. In it, he described how contact between dissimilar metals creates electrical current. He also described a grand new invention based off this principle: the Voltaic pile (better known today as the battery).

In the early 19th century, the Voltaic pile was revolutionary. With the device, scientists could create a steady source of electricity for the very first time. Harnessing electricity led directly to advances in chemistry, physics, and physiology. Even today, we continue to reap the benefits of the battery – a battery is probably even powering the digital display of this article! This invention would prove one of the most important and impactful inventions in history. And, as a testament to that impact, the standard unit of electric potential still bears Volta’s name: the Volt.

While scientists like Volta were busy debating the merits of Galvani’s theory, a third shockwave crashed into lives of non-scientists. As the theory spread, the concept of animal electricity was seized upon by private citizens.

Around the turn of the 19th century, demonstrations of Galvanism became fashionable in high society. Wealthy socialites hosted experiments to see the results firsthand, often to the amazement of their guests. At one memorable dinner party in Turin during the spring of 1792, one guest, the English Baroness Elizabeth Lady Holland, found the electrification of a dead frog so disturbing that  she wrote about it her diary .

Even outside of the social elite, stories of electrified bodies spread through newspapers and media. Public demonstrations took place in town squares and city centers. These demonstrations were made typically made on dismembered animals, until Galvani’s own nephew, Aldini, outdid his fellow scientists by publicly electrocuting a recently executed criminal. His demonstration showed that the dead could be “reanimated” by applying electric shocks to the corpse (1803).

Figure 4. A Galvanized corpse. Published in 1836, this cartoon depicts Galvani’s nephew electrifying a criminal’s corpse.

The macabre scenes of electrified bodies and the idea of reanimation invaded the public zeitgeist. The public fervor even swept up artists and poets like Gothic novelist Mary Shelley. After a summer in Italy discussing Galvani’s work and other scientific discoveries with her husband, poet Percy Bysshe Shelley, and their friend Lord Byron, Mary Shelley invoked similar experiments in her most famous novel, Frankenstein, “ Perhaps a corpse would be re-animated; galvanism had given a token of such things.”  To Shelley and others, animal electricity brought on philosophical and religious questions as well as scientific. Could the dead be brought back to life? What would it mean for the nature of the soul, if humans were nothing more than electrical generators?

Unfortunately for the man who brought animal electricity to the world, Galvani would not have long to contemplate its widely felt implications. In 1798, only seven years after Galvani’s ground breaking publication, Napoleon marched through Italy. Napoleon’s conquest presented Galvani with a choice: swear allegiance to the Emperor’s newly created Cisalpine Republic or be removed from his academic post. Galvani refused. As a religious man, he could not declare allegiance to Napoleon’s atheistic government. With his refusal, Galvani lost his job and died within the year. Largely discredited due to the scientific battle with Volta, Galvani died poor and obscure. But today we know that he catalyzed change in medical and physical science.

Galvani’s story is one of interactions: metal and frogs, scientists and other scientists, geopolitics and a lone professor, science and people’s imaginations. These complex interactions gave rise to an incredible array of new ideas: an understanding of the body’s electrical signaling, entire new fields of study, batteries, and even a timeless monster. Like many great discoveries, the story of Galvani and animal electricity defies easy categorization. It is more than a story about science; it is the story of many fields, from technology to literature. It is a story of excitement and inspiration. It is a story of scientifically-minded people, of religious people, of everyday people.

And, at its core, it is a story of far-reaching connections. print

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Galvani Discovers ‘Animal Electricity’

Luigi Galvani discovered that the spinal cords of a frog carried an electric charge on 20 September 1786.

Would Mary Shelley have conceived of her novel of 1818, Frankenstein , without the work of the Italian scientist Luigi Galvani? Looking back at its creation, she recalled long conversations with Lord Byron and her husband, the poet Percy Bysshe Shelley, about Galvani’s ideas. ‘Perhaps a corpse would be re animated’, she wrote. ‘Galvanism had given token of such things.’

Galvani’s great breakthrough had come on 20 September 1786, when he had discovered – quite by accident – that the spinal cords of a frog carried an electric charge. Galvani believed he had found proof of what he called ‘animal electricity’, an innate force in the body’s nerves. He compared the frog’s muscle fibres to a Leyden jar, an electrical component which stores a high-voltage charge between electrical conductors.

But it’s likely that Shelley had in mind Galvani’s nephew, Giovanni Aldini, who took up his uncle’s work after he died in 1798, defending his reputation and publicising – some might say vulgarising – the concept of galvanism. It was Aldini who, with much fanfare and not a little theatre, tried to use galvanism to resurrect a newly hanged man.

Despite the fact that Galvani himself tried his process on an amputated arm and foot, he seems a more self-effacing man. ‘But let there be a limit to conjectures!’ he writes at the close of the treatise announcing his discovery. His call went unheeded.

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The Real Scientific Revolution Behind ‘Frankenstein’

Mary Shelley’s classic novel was written in a world where the dead twitched.

Italian scientist Luigi Galvani (left) and the steps of a suspended reanimation experiment on frog legs and a sheep. The manicules (pointing hands) illustrate to the reader how the steps should be performed. From “De viribus electricitatis in motu musculari commentarius” by Luigi Galvani, 1792. Courtesy of The New York Academy of Medicine Library

This story is part of our winter Book Club conversation about Mary Shelley’s 1818 novel Frankenstein. Want to participate? Sign up for our newsletter or call our special voicemail at 567-243-2456.

It was an early September evening in 1786. An Italian physician and physicist, Luigi Galvani, lined frog specimens one by one along a parapet, each dangling by the spinal cord from a metal hook.  Then by chance , one of the hooks touched an iron plate, and much to the scientist’s surprise, the frog’s legs began to mysteriously twitch—the dead animal seemingly reanimated with life.

“Behold! A variety of not infrequent spontaneous movements in the frog,” Galvani wrote later in 1792 in his book about his experiments.

Galvani had been conducting a series of experiments on muscular motion in dissected animals when he first observed the contractions and spasms of the frogs’ legs that were stimulated by an electric current. Although Galvani would describe it as “animal electricity,” the phenomenon would later be named “galvanism,” after him. He and others repeated and performed variations of his famous frog experiment and even applied electric stimulation to the human body, both dead and alive. Scientists began to wonder if Galvani had discovered an innate vital force that powered life.

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Demystifying the workings of the human body and living organisms—distinguishing living from dead—was just one of the areas of research that swept across Europe during the Enlightenment, the period of scientific discovery from the late 1700s to the early 1800s. Chemists competed to identify new elements; physicians began to focus on pathological changes from disease; physicists studied the nature of electricity. It created the perfect setting for Mary Shelley’s 1818 novel, Frankenstein , says Thomas Broman, a recently retired science historian specializing in the Enlightenment at the University of Wisconsin, Madison.

The literary movement Romanticism, “itself is a culture that fetishizes genius and the brilliance of young people making a new world,” Broman says. “So there’s such a huge buzz about the genius of scientists and I’m sure [Shelley] is playing on some of this idea, too.”

Shelley was no stranger to current research. She would listen to philosophical and scientific discussions among her circle of intellectual friends. She even journaled about attending a public lecture on the medicinal uses of electricity in London—one form of the many science shows for entertainment and education that was in vogue. Nowhere in the original Frankenstein does she mention the word “electricity,” however, she reveals in the introduction of her 1831 edition that the popular galvanism experiments were a potential impetus for bringing the creature to life.

“It’s very easy to imagine that these kinds of experiments were in her mind, that really informed the way she was thinking about creating artificial life,” says Paola Bertucci, an associate professor of history of medicine at Yale University.

The experiments of Shelley’s time laid down the necessary fundamental research for modern medicine and the technologies of Industrial Revolution, says Broman. Pathological anatomy helped reconceptualize the treatment of disease, while new ideas of atomic combinations led to deeper understandings of chemical compounds.

Galvani’s research and those famous twitching frog legs were the beginning of electricity as we know it, Bertucci explains. The popularity of electric experiments eventually gave way to Alessandro Volta’s invention of the voltaic pile—the early electric battery, she says. And despite being a centuries-years-old experiment, dissected frog legs still kick on laboratory tables—students in physiology labs perform iterations of the electrical experiments that likely influenced the world of Frankenstein .

To dive into the scientific world that Shelley lived in, Science Friday took a peek at the experiments tucked between the pages of late 18th- and early 19th-century texts at the rare book room of the New York Academy of Medicine in New York City with historical collections librarian Arlene Shaner. Books written by scientists like Galvani and his nephew Giovanni Aldini contain electric medical instruments, practices on how to revive the apparent dead, procedures of early skin grafting, and galvanic experiments on human corpses. The vivid and rather macabre depictions are easily reminiscent of Frankenstein .

Historical collections librarian Arlene Shaner. Credit: Daniel Peterschmidt

Table I from Luigi Galvani’s book depicting his various frog reanimation experiments. From “De viribus electricitatis in motu musculari commentarius” by Luigi Galvani, 1792. Credit: Daniel Peterschmidt

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From “General views on the application of galvanism to medical purposes; principally in cases of suspended animation” by Giovanni Aldini, 1819. Courtesy of The New York Academy of Medicine Library

After Galvani’s initial experiments on frogs, scientists took galvanism a step further—Galvani’s nephew, Italian physicist Giovanni Aldini, started sending electric stimuli into the bodies of dead humans.

Aldini noted, “various contractions, sometimes of the fingers, sometimes of the hand, and sometimes even of the whole arm. The fingers bend and unbend very visibly, and sometimes the whole fore-arm is carried towards the chest.”

From “General views on the application of galvanism to medical purposes; principally in cases of suspended animation” by Giovanni Aldini, 1819. Credit: Daniel Peterschmidt

Aldini also conducted a variety of galvanic experiments on large bodied animals like oxen, as depicted above in his 1819 book.

“The size and vigour of the English oxen, generally so well marked, increased the effects of the galvanism,” Aldini writes about an 1803 experiment on an ox in London. “The irritation of the organs was so great, that the whole head was put into most violent agitation.”

From “An Essay on Electricity, Explaining The Principles of that Useful Science; and Describing The Instruments” by George Adams, 1799. Credit: Daniel Peterschmidt.

Electricity was one of the hottest items of discussion throughout the 18th century. Scientists would hold public science shows and lectures at the Royal Society in London as a form of both entertainment and knowledge. “It was very fun for salons, parties, and tricks, and there were a lot of lecturers who would display very vivid phenomena of electricity,” says Thomas Broman. Often, a lecturer would make the hairs on a volunteer’s arm stand on end with electricity, he says. In the illustration above, a scientist demonstrates an electric experiment on a young girl.

From “An Essay on Electricity, Explaining The Principles of that Useful Science; and Describing The Instruments” by George Adams, 1799. Credit: Daniel Peterschmidt

Many medical texts often served dual purposes, containing both information on practices and treatments as well as a catalog of instruments for sale, explains Shaner. George Adam’s essays on electricity, for instance, includes various electrical instruments, from optical to chemical devices.

From “The accidents of human life : with hints for their prevention, or the removal of their consequences” by Newton Bosworth, 1813. Courtesy of the New York Academy of Medicine

In the same vein of searching for the force that powers life, scientists and society troubled over distinguishing states of life and death—especially in victims of drowning. Doctors published manuals on signs of human death, while societies popped up across Europe that disseminated information about how to resurrect those who drowned, such as the Society for the Recovery of Persons Apparently Drowned . A device such as the bellows and pipes depicted above were used for resuscitation.

From “An account of two successful operations for restoring a lost nose from the integuments of the forehead, in the cases of two officers of His Majesty's Army; to which are prefixed, historical and physiological remarks on the nasal operation; including descriptions of the Indian and Italian methods” by J.C. Carpue, 1816. Courtesy of the New York Academy of Medicine

The illustrations above shows a kind of skin grafting, reconstruction procedure of a soldier who had lost his nose. Performed by English surgeon J.C. Carpue, skin from the forehead is sliced and turned down over the nose to restore the lost tissue. The three pages show the different steps and healing process of the operation.

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A surgical medical kit from the 19th century. Some of the tools are actually similar to what might be found in today’s surgical rooms, says Arlene Shaner. Credit: Daniel Peterschmidt

In human anatomy, “more and more specific knowledge of the body’s structure was really beginning to inform the way that people were thinking of causes of disease,” says Thomas Broman. Doctors took notice to the “different pathological changes that the body could undergo when falling ill.” These ideas propelled modern medicine forward.

Credit: Daniel Peterschmidt

Special thanks to Arlene Shaner and the New York Academy of Medicine.

Meet the Writer

About lauren j. young.

Lauren J. Young was Science Friday’s digital producer. When she’s not shelving books as a library assistant, she’s adding to her impressive Pez dispenser collection.

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In the late 18th century, frogs were the talk of the Italian scientific establishment. Two prominent experimentalists, Luigi Galvani and Alessandro Volta, presented novel theories of animal and chemical electricity that they attempted to defend by reference to scientific instruments. At issue was the nature of nervous response and muscular motion in the frog. The Whipple Museum's voltaic piles, Leyden jars, and electro-galvanic machine embody distinct interpretations of the frog's ambiguous body.

In the 1780s, the Bolognese physician Luigi Galvani (1737-1798) conducted a vast range of experiments on electricity's effect on "prepared" frog specimens - that is, frog legs severed at the base of the spine, with nerves exposed. These studies culminated in his Commentary on the electrical force of muscular motion of 1791, which quickly seized the attention of the physical scientist and Galvani's eventual rival, Alessandro Volta (1745-1827).

Galvani's first crucial result in his frog experiments was the product of good fortune: while investigating the effect of atmospheric electricity on "prepared" specimens, Galvani and his assistants hung frog legs from an iron railing, with brass hooks dangling from their spinal nerves. One hook touched the railing, and the attached frog's leg kicked. Placing the legs and hooks on other metals and doing the same had a similar effect, but nothing happened when they placed the frog on non-conducting materials like wood, glass, or resin.

Instruments as Frogs: the Leyden Jar and Voltaic Pile

By the late 18th century, natural philosophers knew that electricity could stimulate muscular motion. What kind of electricity was it, though, and how was it produced? To answer this question, Galvani and Volta each pointed to an instrument used for storing or producing electric current whose operation was more convincingly understood than the frog's kick: Galvani said the frog's leg works like a Leyden jar, and Volta compared it to his own, new invention, the battery pile.

When Galvani hung a frog's leg over his iron banister and saw it kick, a familiar electrical instrument came to mind:

"These results surprised us greatly and led us to suspect that the electricity was inherent in the animal itself. An observation that a kind of circuit of a delicate nerve fluid is made from the nerves to the muscles when the phenomenon of contractions is produced, similar to the electric circuit which is completed in a Leyden jar, strengthened this suspicion and our surprise." (1)

The twitching leg reminded Galvani of the Leyden jar. The Leyden jar was one of the first and most important electrical tools to spread throughout Europe. Pieter van Musschenbroek invented it around 1745 in the Dutch town of Leiden, from which the jar derives its name. Another 'electrician' named Ewald Georg von Kleist, however, invented a jar with the same capabilities independently, and roughly simultaneously.

By filling the jar with water, then directing an electrical current into that water via a metal cap, one can store or 'condense' current within the jar. The water's charge in turn produces the opposite electrical charge in the outer metal plate. 'Electricians' would perform stunning displays of electrical power by establishing a circuit between the water and the outer plate. We now call this a 'capacitor' or 'condenser.'

In his experiments on electricity and frogs, Luigi Galvani imagined that the frog's muscle and nerve acted like the two sides of a Leyden jar. Establishing a circuit between them allows the discharge of 'animal electricity' analogous to the artificial electricity of the jar. Animal motion resulted from distributions of charges in nerves that would, when sufficiently strong, discharge relative to muscles and cause them to contract. To Galvani, the frog comprised an ensemble of capacitors. Electricity created and used by animal bodies for this purpose constituted 'animal electricity.'

Physicians later applied this idea to medicine by creating machines for administering therapeutic shocks - see The Electo-galvanic machine, below .

Volta took Galvani's brass hook experiment to demonstrate an opposing claim: the frog's body does not produce its own electrical current, which is merely conducted by the brass and iron through an imbalance of charges. Instead, the brass and iron in contact with the moist, conducting frog body produce 'artificial' electricity that makes the frog kick. This reinterpretation amounted to the entirely new theory of 'contact electricity,' which Volta mobilised in the invention of his battery pile.

Volta first created the pile in 1799 to demonstrate the capacity of moistened metals to produce electric current through contact alone. Little is known about the many voltaic piles owned by the Whipple Museum, in part because it was such a common and generic scientific tool. Many were produced in early 19th century England according to Volta's general design. This example consists of alternating copper and zinc plates separated by 'cells', or cloth pads moistened with saltwater or acid.

Electro-galvanic machine

The electrical nature of muscular motion that Galvani and Volta investigated did not only spur further physiological research, but also provided foundations for innovative medical therapies.19th century physicians and scientists applied Galvani's model of the frog's muscular motion, which he considered the product of carefully balanced and imbalanced electrical currents, to new forms of medical therapy, which they called "Galvanism." Electrical medicine gave rise to new machines and new types of treatment.

The Whipple Museum's Electro-Galvanic Machine was built in the late 19th century (likely between 1886 and 1893) by Horne, Thornwaite, and Wood at 123 Newgate Street London, where they ran an instrument company. Ironically, perhaps, given their inventors' disagreements, the Galvanometer was powered by a voltaic pile. Metal electrodes channelled current through specific contact points on the body, each selected for a precise medical purpose.

Covering the lid's inside surface is a pamphlet on "Administering Medical Galvanism". Scientific studies on the medical uses of Galvanism proliferated in the second half of the 19th century. They claimed, for its uses, the healing of paralysis and other disorders related to the nervous stimulation of muscles. Some used Galvanian stimuli to treat hoarseness, ocular distortions apparently due to anemia, asthma, and constipation. Several obstetricians tried to induce and facilitate labour by administering shocks to pregnant women, which usually met with tragic results.

• A. Mauro, 'The Role of the Voltaic Pile in the Galvani-Volta Controversy Concerning Animal vs. Metallic Electricity', Journal of the History of Medicine and Allied Sciences (Oxford: Oxford University Press, 1969).

Henry Schmidt

Henry Schmidt, 'Frogs and Animal Electricity', Explore Whipple Collections, Whipple Museum of the History of Science, University of Cambridge.

Next Article: Frogs and Physiological Instruments in 20th Century Cambridge

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• September 2011
• Foundations

Animal Electricity, circa 1781

How an italian scientist doing frankenstein-like experiments on dead frogs discovered that the body is powered by electrical impulses..

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How Luigi Galvani Invented The Battery And Made A Dead Frog Jump

How did a Galvani make a dead frog jump?  And how did that lead to the battery?  And, hey, didn’t Volta invent the first battery?  Well, I’ll tell you and along the way I will talk about professional misconduct, a surprising accident, the inspiration for Frankenstein and the building block of life.

Table Of Contents

Why galvani was playing with electricity, galvani and the shocked dead frog, galvani and atmospheric electricity, galvani and the first battery, video script download.

Sometime in 1790 or 1791 an Italian professor of anatomy named Luigi Galvani was playing with electricity machines and hoping to find something interesting to publish. 

See, Galvani was a member of the Academy of Sciences of the Institute of Bologna and he needed to submit a research paper every year.  For the previous four years he had published work on the hearing of various animals. 

However, that year his work was “poached” from a rival so Galvani needed a new topic – and quickly.

Galvani thus turned to the “newish” field of electricity and got several assistants to help him. 

He had static electricity machines that you could spin to produce large static charges and jars called Leyden jars that could store the charge and give it in a terrifying jolt when you connected them in a circuit. 

One day, unrelated to his electricity experiments, he happened to put a dissected headless frog on the table while his assistants were running these electrical experiments. 

He never said why he why he was cutting up frogs in the first place. 

A popular myth is that he was making frog soup for his sick wife.  However, it seems much more likely that he was dissecting the frog for an anatomy lecture (he was an anatomy professor!) 

Anyway, a frog was on a table near an electric machine. 

This is how Galvani described what happened next, “I had dissected and prepared a frog and I had put it on a table where there was an electric machine.

As soon as one of my aides, by accident, touched the internal nerves of the frog with a scalpel, at once he saw all the muscles go into violent convulsions.” 

Galvani was deeply surprised by the frog “jumping” and did a series of bizarre and macabre experiments, like frogs in a jar and frogs in a circle to determine what would make the frog dance. 

He also moved on to other animals and found that all animals would display this behavior to some extent.

Galvani (or honestly his assistant) accidentally discovered two things with this. 

First, they found that frog legs are an extremely sensitive “machine” for detecting electricity – superior by a factor of five thousand to anything non-biological available at the time.  

Secondly, and more importantly, Galvani created the study of how electricity works in living systems.  He found that muscles contract with electricity and nerves send messages with electricity. 

In truth, electricity is the building block of living systems.  We think with electricity, we hear and see and smell with electricity, our hearts pump with electricity, and our muscles move with electricity. 

This is not just true for frogs, ALL animals’ living functions are electrically based.  

Galvani called it “animal electricity” and felt that all living beings had it inside them, especially in the nerves and muscles. 

Now it took a further 150 years to really understand the complex beauty of the organic system but Galvani started us on that path!

Galvani then decided to move his frog experiments outside to see if thunderclouds could make the frog jump as well as static electricity would. 

This was 38 years after Benjamin Franklin flew his kite in a storm so he was not surprised to find that the frog jumped theatrically in thunderstorms. 

However, something else happened that was truly unexpected, sometimes the frog legs would jump on clear days with no static electricity involved AT ALL. 

What was going on?  At first, Galvani wondered if the frog collected atmospheric electricity from past storms. 

However, Galvani was a very careful scientist and realized it had nothing to do with the weather it had to do with the outdoor gate!  See, he had iron railings surrounding the garden that he hooked his frogs on. 

He also used copper hooks to transport the frogs. 

It was this combination, the iron and the copper that caused the frog to convulse. 

When he took the frog inside he could make a frog dance with just a piece of copper and iron!  Crazy huh? 

This is a major find, putting both copper and iron into a frog’s body produces electricity – with no rubbing globes or thunderstorms in sight. 

Galvani decided that the frog produced electricity because it had been alive in the past – he thought he was reanimating the frog ala Frankenstein (whose author was inspired by Galvani’s research by the way)!

Galvani published his work in 1791 and it became an international sensation, especially among anatomists. 

Suddenly, there was a new way of examining how muscles move and nerves communicate. Galvani’s theory of “animal electricity” created a link between electricity and what makes things alive. 

Galvani made the spark of life literal.

Galvani didn’t know it, but he had also inadvertently invented the first battery – the acid of the frog’s leg reacted with the copper to add electrons and reacted with the iron to remove electrons. 

The electrons then flowed through the frog’s leg from the copper to the iron making the frog leg jump.  In terms of physics, it was a completely useless battery as it discharged inside itself. 

This is why most people do not consider Galvani’s “invention” a battery.  

However, there was a man named Alessandra Volta who was supposed to be Italy’s leader in electricity who became obsessed with jealousy over Galvani’s fame. 

Volta started a war with Galvani, which led to him building the first non-biological battery. 

This is the battery that changed the world, which is why electromotive power is measured in Volts. 

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Electricity & Life

Luigi Galvani (1737-1798) was a physician from Bologna, Italy, whose research into the anatomy and physiology led him to the observation that electrical stimulation caused a dead frog’s leg to twitch. Galvani claimed that this unexpected result demonstrated that muscles and nerves contained animal electricity. Physicist Alessandro Volta proposed an alternative explanation for the twitch, and in the process of disproving Galvani, discovered electrical current.

Galvani began his research in 1766, when he was appointed by the Senate of Bologna to curate the city’s anatomical museum. He was also a lecturer on medicine at the University of Bologna, where he had received his medical training and was expected to give an annual researcher paper. His early research was on the hearing of birds and humans. In the 1770s, he began documenting the physiology of the nerves and muscles of the frog. He offered papers on the effects of stimulation and opiates on the nerves of frogs.

In 1780, Galvani attempted to standardize his research methods by preparing carefully dissected frogs for study. He wanted to understand how static electricity generated responses in the specimens. Galvani and his assistants dissected each frog’s spinal cord, crural nerves, and lower limbs and removed the skin to expose nerves and muscles. As they prepared these experiments, Galvani’s team began noticing strange phenomenon. According to one story, an assistant was applying a scalpel to a frog’s crural nerve when a nearby electrical generator sparked. The frog’s leg twitched.

Galvani found that he could produce a muscle contraction if he put a frog’s legs on a sheet of glass, touched a crural nerve to a ground conductor, and then drew a spark from an electrostatic generator. This occurred even though the spark did not directly touch the frog’s legs. In fact, it worked even when the frog’s legs were far from the machine.

Along with his experiments using electrical generators, Galvani tested the application of lightning to the frog’s legs. He attached brass hooks to the spinal cords of frogs and hung them on iron rails. Contractions occurred, as expected, during flashes of lightning, but they also happened when the weather was good. Galvani also determined that these contractions could be produced in the laboratory by putting a brass hook through the frog’s spinal column, putting the leg on an iron plate, and pressing the brass hook against the iron plate.

As he witnessed biological matter come to life with a spark, Galvani interpreted the results through the theory of animal electricity. Like many other eighteenth century scientists, he believed that animals possessed a fluid in their nerves and muscles similar to ordinary electricity. The muscles, he concluded, were like a Leyden jar that held electricity and the nerves were conductors. Within the body, this animal electrical fluid was positively charged as circulated from brain to muscle through the nerves. Outside electricity had a negative charge that upset the body’s internal balance, causing a twitch. Galvani published these startling findings beginning in the mid-1780s, and released a major study, “Notes on the electrical forces in the movement of muscles,” in 1791.

Alessandro Volta of the University of Pavia took an early interest in Galvani’s work, but soon began to doubt the theory of animal electricity. He argued that electricity could be produced without the intervention of animal tissue, such as through the contact of two metals in a moist environment. Galvani’s frogs, he discovered, were not vessels of electrical current, but instead held the potential for a reaction when exposed to metal: they were conductors of electricity, not its source.

Galvani and Volta’s competing positions produced a decade of experiments that led to Volta’s development of the first battery in 1800. Scientists recognize Galvani as the discoverer of bioelectricity, even as his rival Volta’s discovery of electrical current remains the lasting legacy of their experiments.

Further Reading

Galvani and the Frankenstein Story

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The Early History of the Oscilloscope: Amber and Frog Legs

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Here is the first part in a series of the history of the oscilloscope, building up from the discovery electricity to the first rudimentary measuring tools using frog legs.

The oscilloscope is one of the most useful tools in the engineer or hobbyist’s repertoire—it takes measurements of voltage and displays it in a waveform over time to convey information on frequency, amplitude, and noise from just a quick glance.

Found in nearly every any workshop or lab where electrons are being used, many may take for granted all that transpired to bring the oscilloscope into existence. The journey is interesting and took the culmination of many accidental discoveries and strange observations. 

Here is the first part in a series of the history of the oscilloscope, building up from the discovery electricity to the first rudimentary measuring tools using frog legs.

Hopefully, the next time you are observing a crisp, smooth sine wave, you can appreciate the oscilloscope’s journey.

If you'd like to jump ahead to further in history, you can see the other two parts of this series here:

• Oersted’s Laws and Hand Drawn Waveforms
• Visualizing with Light, the CRT, to the Modern Oscilloscope

Electricity: An Intellectual Curiosity

Electricity is a natural phenomenon (think lightning, or electric eels), but it’s early manipulation by humans looks quite different than what we have today. Before the oscilloscope could even be needed as a tool, ancient cultures were aware of the existence of static electricity when rubbing a material such as amber against fur. Although, at this time it was believed that the static electricity buildup was actually magnetism. 

In the 1600s, a more systematic investigation of static electricity was performed by William Gilbert, an Englishman who was all at once a philosopher, a physician, and a physicist. He is most famous for his book, de Magnete , in which he differentiated the magnetizing effects of lodestone from the static charge attraction by rubbing amber. He called this latter phenomenon "electricus", rooted in the Greek word for amber, "elektron".  

Lodestone is a naturally occurring, magnetic mineral. Magnetism and static electricity, while related in some ways, were mistaken to be the same thing. Image courtesy of Mira Images .

In subsequent centuries many other scientists would begin to build upon knowledge of electricity. One of the most well-known being Benjamin Franklin who theorized the positive and negative elements of electricity, and performed the kite experiment: tying a key to a kite during a lightning storm to prove that it was flowing electricity. 

The 19th century would prove to be particularly enlightening—the era of Thomas Edison, Nikola Tesla, Alexander Graham Bell, among others, would create an explosion of electronic inventions that would become an essential part of daily life for the average person, such as the lightbulb, alternating-current, and the telephone. It’s during this time that tools to measure electricity became more important to the innovation that was occurring at the time. 

Jumping Frog Legs: the Frog Galvonoscope

In the 18th century, frogs were a commonly used animal in scientific experimentation. Their muscular, vascular, and neural systems were easy to observe, they were readily available, and reproduced quickly. 

In 1781, while dissecting a frog for an unrelated experiment, an electric discharge from a scalpel caused the legs of a frog to twitch when it was in contact with a nerve. Luigi Galvani, an Italian physicist, physician, and biologist, then discovered that creating an electrical connection between the nerve and the muscle of the frog’s legs would cause the leg to twitch when voltage was applied. This lead to the « Frog Galvanoscope », a tool that sounds a little macabre but proved to be useful for future experiments using electricity.

The frog galvanometer was gruesomely constructed by removing a frog’s leg with it’s sciatic nerve, skinning the leg, and then creating a connection between the nerve and the foot of the frog with wire. The leg was then inserted into a glass tube with the nerve protruding. The frog galvanometer would twitch when a circuit is created and broken, and was very sensitive, which is part of why it remained in use well after the electromechanical galvanometer was invented in1820. The drawback was that obviously the leg would need to be regularly replaced, and that it’s sensitivity was directly linked to how recently the frog had been alive. Interestingly, frog legs that were more stale were able to convey the direction of a current: from nerve to foot, the leg would only twitch when a circuit was created, and from foot to nerve, the leg would twitch only when a circuit was broken. 

A frog leg galvanoscope which twitched when a circuit was created or broken. Image belongs to the public domain and sourced from Elements of Experimental and Natural Philosophy, fig. 348, London: Henry G. Bohn, 1861.

Galvani theorized that the frog galvanometer was proof of electricity as a vital force in living things. However, the eventual invention of the voltaic pile demonstrated that electricity could be produced using non-biological materials. 

As a summary, our early measurements of electricity involved fairly rudimentary methods: we first knew it existed when amber was rubbed against fur and was able to attract other objects like feathers. Then, by accident it was discovered that frog legs could be used to detect electrical connections with high sensitivity. While these tools told us a little bit about electricity, it still doesn't go into the sort of detail we can get today with the modern oscilloscope, but were among the first steps towards it. 

In part 2, we’ll cover the invention of the electromechanical galvanoscope, and the oscillogram.

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Thank you for what promises to be an interesting and useful article. Should the work of Ampere, Voltaire and (especially) Faraday be mentioned / acknowledged? Cheers, Mark

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Science News

‘we are electric’ delivers the shocking story of bioelectricity.

The book chronicles an underexplored area of science and how it could advance medicine

Bioelectricity has profound implications for health, but the history of this emerging field is charged with skeptisism.

lekkyjustdoit/istock

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By Meghan Rosen

March 2, 2023 at 8:00 am

We Are Electric Sally Adee Hachette Books, $30

It took just a 9-volt battery and a little brain zapping to turn science writer Sally Adee into a stone-cold sharpshooter.

She had flown out to California to test an experimental DARPA technology that used electric jolts to speed soldiers’ sniper training. When the juice was flowing, Adee could tell. In a desert simulation that pit her against virtual bad guys, she hit every one.

“Getting my neurons slapped around by an electric field instantly sharpened my ability to focus,” Adee writes in her new book, We Are Electric . That brain-stimulating experience ignited her 10-year quest to understand how electricity and biology intertwine. And she’s not just talking neurons.

Bioelectricity, Adee makes the case, is a shockingly under­explored area of science that spans all parts of the body. Its story is one of missed opportunity, scientific threads exposed and abandoned, tantalizing clues and claims, “electroquacks” and unproven medical devices — and frogs. Oh so many frogs.

Adee takes us back to the 18th century lab of Luigi Galvani, an Italian scientist hunting for what gives animals the spark of life. His gruesome experiments on twitching frog legs offered proof that animal bodies generate their own electricity, an idea that was hotly debated at the time. (So many scientists repeated Galvani’s experiments, in fact, that Europe began to run out of frogs.)

But around the same time, Galvani critic Alessandro Volta, another Italian scientist, invented the electric battery. It was the kind of razzle-dazzle, history-shaking device that stole the spotlight from animal electricity, and the fledgling field fizzled. “The idea had been set,” Adee writes. “Electricity was not for biology. It was for machines, and telegraphs, and chemical reactions.”

It took decades for scientists to pick up Galvani’s experimental threads and get the study of bioelectricity back on track. Since then, we’ve learned just how much electricity orchestrates our lives, and how much more remains to be discovered. Electricity zips through our neurons, makes our hearts tick and flows in every cell of the body. We’re made up of 40 trillion tiny rechargeable batteries, Adee writes.

She describes how cells use ion channels to usher charged molecules in and out. One thing readers might not expect from a book that illustrates the intricacies of ion channels: It’s surprisingly funny.

Chloride ions, for example, are “perpetually low-key ashamed” because they carry a measly -1 charge. Bogus medical contraptions (here’s looking at you, electric penis belts) were “electro-foolery.” In her acknowledgements, Adee jokes about the “life-saving powers of Voltron” and thanks people for enduring her caffeine jitters. That energy thrums through the book, charging her storytelling like a staticky balloon.

Adee is especially electrifying in a chapter about spinal nerve regeneration and why initial experiments juddered to a halt. Decades ago, scientists tried coaxing severed nerves to link up again by applying an electric field. The controversial technique sparked scientific drama, but the idea of using electricity to heal may have been ahead of its time. Fast-forward to 2020, and DARPA has awarded $16 million to researchers with a similar concept: a bio­electric bandage that speeds wound healing.

Along with zingy Band-Aids of the future, Adee describes other sci-fi–sounding devices in the works. One day, for example, surgeons may sprinkle your brain with neurograins, neural lace or neural dust , tiny electronic implants that could help scientists monitor brain activity or even help people control robotic arms or other devices ( SN: 9/3/16, p. 10 ).

Such implants bring many challenges — like how to marry electronics to living tissue — but Adee’s book leaves readers with a sense of excitement. Not only could bioelectricity inspire new and improved medical devices, it could also reveal a current of unexpected truths about the body.

As Adee writes: “We are electrical machines whose full dimensions we have not even yet dreamed of.”

Buy  We Are Electric   from Bookshop.org.  Science News  is a Bookshop.org affiliate and will earn a commission on purchases made from links in this article.

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Neuroscience for Everyone!

• Experiments

Microstimulation of Neurons and Muscles

It's the 1780's all over again. Investigate excitability of nervous and muscle tissue with this experiment.

In this lab you will:

• Learn how to prepare a cockroach leg for micro stimulation.
• Test how different stimulations cause spikes in motor neurons.
• Observe the difference between sensory and motor spiking patterns.
• Investigate how different types of stimulations affect the generation of action potentials in a cockroach leg preparation.

Before doing this lab you should understand:

• How neurons communicate with muscle cells
• How electrical stimulation can cause a muscle contraction

After doing this lab you should be able to:

• Explain how a nervous system controls muscle movement.
• Describe how distinct movements are caused by specific spiking patterns.
• Design an experiment to map ideal frequencies for stimulation.

Educational Standards

Next generation science standards.

Common Core Standards for Science and Technology (Grades 6-8)

Common Core Standards - Science and Technology

Middle school (grades 9-10).

High School (Grades 11-12)

PLTW Objectives

Introduction.

Long before scientists were able to record spikes, they were able to stimulate the nervous system using primitive batteries called Leyden Jars. Since nerves use electricity to communicate, they can be manipulated with electricity as well. Luigi Galvani, an Italian scientist in the 1700's, discovered that electricity applied to the nerves of frog legs caused the large muscles to twitch.

Such discoveries led to debates at the time as to whether "animal electricity" was different from the electricity during lightning storms. Galvani decided to test this as well tested this by hanging frog legs off his back porch during thunderstorms and watching the legs twitch. By demonstrating that the electricity from lightening could also stimulate nerves, he showed that electricity was the same whether it flowed through a nerve, or was produced in a thunderstorm.

Luigi Galvani tested whether electrical energy from storms was the same electricity found in nerves in the body by running a wire up to the roof of his house and connecting it to nerves in frog legs. When lightening struck the wire, the electricity stimulated the frog nerves causing the legs to move. His experiments showed that the electricity found in nature and the electricity found in neural systems are the same.

"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 endured with vital warmth." -Mary Shelley, 1818

After demonstrating that electricity can indeed stimulate nervous system and muscle tissue, scientists went on to prove that neural tissue generates its own electricity. This led to the beginnings of contemporary neuroscience.

In another famous experiment, German medical scientists Eduard Hitzig and Gustav Fritsch in 1870 applied electric current to the exposed cerebral cortex (wrinkly part of brain) in dogs in their kitchens, which people thought was odd even back then. Hitzig showed that stimulation of different parts of the brain can cause different types of movements.

Today, such central-stimulation/motor-sensory-output techniques are used in patients with neurological disease, most notably those afflicted with Parkinson's disease. By inserting a small, long electrode into a specific part of the brain called the subthalamic nucleus, the shaking and tremors associated with the disease can be lessened. However, sometimes stimulating the brain can also cause side-effects, like increased gambling and other compulsive behaviors. Today, some advanced research groups are designing small chips that stimulate the nerves of the eye as a cure for blindness.

Different Synapses for Different Purposes

Earlier we learned about action potentials (APs) and the neuron-neuron synapses that exist in the central nervous system and allow us to process stimuli. However, if the neurons couldn’t also interact with other types of cells, they would be useless. The interface between neurons and muscle tissue takes place in special synapses, called neuromuscular junctions, that allow neurons to stimulate muscle cells. In the central nervous system, webs of interacting neurons (called convergent connections) stimulate each other and exchange information. However, a postsynaptic muscle cell is normally innervated (activated) by just a single presynaptic motor neuron (MN).

Motor neurons connect to muscles at a specialized region of the muscle membrane called the end-plate, and these specialized synapses between motor neurons and skeletal muscle cells are called neuromuscular junctions. Acetylcholine (ACh) is released by the axon terminal from the MN, which directly opens voltage-gated Ca+2 ion channels in the muscle membrane that allows Ca+2 to enter the terminal with each action potential. Motor neurons excite the muscle by opening ion channels at the end-plate, producing a large amplitude end-plate potential that rapidly activates voltage-gated Na+ channels and produces an action potential that propagates along the muscle fiber and generates movement.

We've also conducted our own research into this topic!

Dagda RK, Thalhauser RM, Dagda R, Marzullo TC, Gage GJ (2013) Using Crickets to Introduce Neurophysiology to Early Undergraduate Students . Journal of Undergraduate Neuroscience Education (JUNE), Fall 2013, 12(1):A66-A74.

Microstimulation Electrode

The microstimulation electrode will act as a conduit between your electrical signal generator and the cockroach. The electrode will consist of an audio cable that plugs into your signal generator as a means to deliver the stimulation to the cockroach. You can choose to solder either pins to your audio cable, similar to those used in Lab 1, or use alligator clips that can be attached to the electrodes that come with your SpikerBox.

Electrical Signal Generator (ESG)

There are many programs that can generate electrical stimuli ideal for this lab. If you are using an iPhone or iPad, these free apps can be found at the iTunes store at the following links:

If you are using a PC, you can use this online software:

Additionally, you can simply download various frequencies as MP3s and play them through any MP3 player. Here is a website from which you can download free frequencies appropriate for this exercise:

Exercise 1: Cockroach Leg Microstimulation Preparation

Trouble-Shooting your Cockroach Leg Set Up If your cockroach leg does not move in response to the audio stimulus, there are some simple checks you can to ensure that your experimental system is set up correctly. Check Your Signal Generator: Check to be sure that you have your electrode plugged into the audio out jack and that the tone is being produced. You should be able to hear a 200 Hz tone at half volume with EXTERNAL SPEAKERS. If you do not hear a tone, you may need to adjust your audio settings. Test Whether Your Cockroach Leg is Alive: If you can produce a tone with your ESG but the leg still does not move then check to see that your cockroach leg is alive. Using the protocol in Lab 1: Exercise 1, use your SpikerBox electrodes and speaker to ensure spikes are still being produced by the neurons in the leg. Check your Electrode Placement: Check to be sure that you have placed one electrode in the coxa and one in the femur (see diagram to the right). Get Extra Help: Consult with your teacher if you continue to have problems stimulating your cockroach leg.

After you have your cockroach leg apparatus working, please move on to exercise 2.

Alternate Version of Exercise 1

You can run a simplified version of this experiment using a small speaker and asking the students to whistle.

Exercise 2: Response of Cockroach MNs to Amplitude and Frequency

Below is an example with our results

Discussion Questions