The Cruel Animal Testing Behind Thomas Edison’s Quest to Show the Dangers of Alternating Current

This story originally appeared in our November/December 2021 issue as “Cruel Inventions.” Click here to subscribe to read more stories like this one.


The crowd in the auditorium had no idea what they were about to witness, but the appearance of the dog put them instantly on guard. It was July 1888, at Columbia College in New York, and an electrician named Harold Brown had dragged a 76-pound Newfoundland mix onstage and forced it into a wooden cage surrounded by wire mesh.

While the dog cowered, Brown read a paper about the merits of alternating current (AC) versus direct current (DC), with an emphasis on how alternating current was deadlier. Upon finishing, he proceeded to do what everyone present feared, wrapping wet cotton around the dog’s right forelimb and left hind limb, then wrapping the cotton with bare copper wire. The wire was connected to a generator, and when everything was ready, Brown flipped the switch.

After each pulse — some AC, some DC — the dog howled and quaked, and once slammed so hard against the cage that its head ripped through the wire mesh. Eventually, after an AC pulse, it died. One witness said the demonstration made a bullfight look like a petting zoo. Brown, meanwhile, was elated. He felt he’d proved his main point: that AC was deadlier than DC, since AC had killed. He knew this would be music to the ears of his benefactor, too, the man who’d sponsored the torture of the Newfoundland as well as several other animals — that American saint, Thomas Edison.

We all know the story. Despite less than three months of formal schooling, Thomas Alva Edison, through a mixture of gumption and genius, helped invent (or at least develop) dozens of innovative technologies — stock tickers, vote recorders, movie cameras, fire alarms, and more. And while Edison didn’t invent the lightbulb, he and his team of tinkerers did turn a dim, fragile, expensive fire hazard into a cheap, reliable device capable of illuminating the world.

(Credit: All Illustrations by Jay Smith)

That said, Edison could be a real bastard sometimes. He and his assistants all put in grueling hours, regularly working past midnight and sleeping in closets at the lab. But Edison alone hogged the glory for “his” inventions. He was a backstabbing businessman, too. Many people agreed with one executive who sneered that Edison “had a vacuum where his conscience ought to be.”

In the 1880s, Edison came up with his killer idea: wiring cities for electricity. Even at that time, the residents of most big cities walked around beneath a cat’s cradle of wires strung overhead. These were mostly telegraph and arc-lighting wires, specialized for one purpose and restricted to certain businesses. Edison proposed threading electrical wires into every business, and even into people’s homes. What’s more, Edison’s wires wouldn’t be restricted to one purpose, but would supply power for everything — motors, looms, lightbulbs, you name it.

He understood, as few contemporaries did, just how revolutionary electricity would be — and he wanted to be the man to power America. It was a grand vision. But scientists with delusions of grandeur like this often fall for the meansend fallacy. They convince themselves that their research will usher in a scientific utopia, and that the bliss of that utopia will supersede, by many orders of magnitude, any suffering they’re causing in the short term. That’s certainly the stance Edison took with electricity and animals. However, as history shows, when we sacrifice morals for scientific progress, we often end up with neither.

A Bright Idea

There was one big problem with Edison’s plan to wire cities: His patents relied on direct current. Direct current is like a river, a flow of electrons= in one direction only. Alternating current, in contrast, is like a fast tide: The electrons flow first one way, then another, alternating direction dozens of times per second.

Alternating current (AC) generators like this were used in public demonstrations involving dogs and horses to show that (allegedly) AC was deadlier than direct current.

The problem with direct current was that DC powerlines — which carried the electricity from power plants into homes and factories — needed fat, expensive copper wires, while AC systems didn’t. As a bonus, thanks to higher electrical voltage, AC systems didn’t need to have power plants every few blocks; a single plant could serve a whole city. All these factors put Edison’s plan to wire cities with DC at a big disadvantage.

Still, alternating current back then did have one major downside — poor equipment. Unlike with DC, no Edisons had invested their time and genius in making good, reliable AC motors, generators, and transmission gear. As a result, Edison believed that his superior machinery — coupled with his glittering public reputation — would overcome the high cost of plant construction and copper wires and give him a decisive edge in the marketplace. It all might have worked out that way, too, if not for a young Serbian immigrant named Nikola Tesla.

After studying electrical engineering in Europe, the 28-year-old Tesla traveled to the United States in 1884; he arrived with 4 cents, a book of poems, and a glowing letter recommending him to Edison. Impressed, the 37-yearold Edison hired Tesla as an engineer, but the two clashed over scientific differences. Edison favored DC, while Tesla believed the future belonged to AC. After quitting the job, Tesla landed with entrepreneur George Westinghouse, who was investing heavily in AC technology.

For Edison, what historians now call the War of the Currents was only partly about money. Yes, he wanted to fund his beloved research lab, but he’d also made his reputation as an electrical wizard, and the thought of being bested in this arena enraged him and threatened his scientific ego. Losing would threaten not only his bank account but his sense of self; the danger was personal. He therefore began slandering AC power in newspapers, claiming it would kill people left and right.

And Edison soon decided that smears weren’t enough. He needed to show people the dangers of AC — make them cringe. In short, in a dog-eat-dog world, he decided the best way to get ahead would be to kill some actual dogs.

Shocking Science

Brown, who led the demonstration at Columbia, was an electrician who more or less worshipped Edison, going so far as to write an incendiary letter to a newspaper denouncing AC. But his diatribe was criticized by several engineers, who maintained that he had too little evidence to support his claims about the dangers of AC. So despite having never met Edison, Brown wrote and asked whether he could use the labs there to generate more evidence — by helping Edison electrocute dogs.

To Brown’s surprise, Edison agreed. In truth, opening up his lab to strangers wasn’t unusual for Edison, who could be quite generous at times. In this case, he even loaned Brown his top assistant to help out. What was unusual here were the conditions Edison put on the work. Normally Edison encouraged collegiality and the open exchange of ideas — the scientific ideal. But he told Brown to keep mum about these experiments. He also restricted Brown to working at night, so that people wouldn’t hear the howls.

Someone posted a sign near Edison’s lab offering a quarter apiece for stray dogs, and local ruffians came through by capturing them in droves. Brown planned to electrocute the mutts systematically, but in reality, the work was haphazard. The dogs differed wildly in size — setters, terriers, Saint Bernards, bulldogs — and he zapped them with both DC and AC at anywhere from 300 to 1400 volts. The results were nevertheless consistent — an uninterrupted litany of suffering.

After a month of this, Brown felt confident enough to arrange for the demonstration described above, where he tormented a Newfoundland mix at Columbia. The newspaper coverage was outraged, and any normal man would have slunk away in shame. Brown, in contrast, staged another demo a few days later, killing three more dogs with alternating current and allowing doctors to dissect them afterward. All in all, he reported to Edison’s assistant, the experiments were a “fine exhibit” about the dangers of AC.

Others disagreed. Not only was Brown being cruel, they argued, but his experiments proved nothing. In shocking some of the dogs with DC first, he’d battered and weakened them, making it impossible to determine how much each type of current had contributed to their deaths. Furthermore, dogs were small animals. If humans were shocked with AC, there was no guarantee they’d react the same way.

In response to these criticisms, Brown held yet another demonstration in December 1888, at Edison’s lab. This time he electrocuted big animals, and used AC alone to do so. He started with a 124-pound calf, attaching an electrode between its eyes; 770 volts dropped it.

Thomas Edison (Credit: Everett Collection/Shutterstock)

Eventually, Edison’s team would kill 44 dogs, six calves, and two horses in their quest to discredit alternating current. But none of these deaths did any good — Westinghouse continued to crush Edison in the marketplace. By the end of 1888, Edison’s company was building and selling enough equipment to power 44,000 lightbulbs per year. Westinghouse sold enough equipment to power 48,000 lightbulbs in October 1888 alone.

Edison eventually conceded defeat in the War of the Currents. Few people in history can match his record of innovations, but his beloved direct current played almost no role in the 20th-century revolution in cheap electric power transmission. The real shame was that he didn’t bow out with grace, and spare those horses, calves, and dogs the pain and indignity of electrocution.

Animal Testing Today

It might be tempting to excuse Edison and Brown’s behavior on the grounds that theirs was a different era, a time when society simply didn’t treat animals well. But many people back then (such as Voltaire and Samuel Johnson) did protest cruel scientific research, and had been doing so long before Edison’s day.

Conditions have clearly improved since Edison’s time, but experiments involving animals remain controversial today, even among some scientists. This is partly due to the sheer number of animals that die. Medical research exploded in the second half of the 20th century, and by the year 2000, American scientists alone were going through half a billion mice, rats, and birds per year, plus dogs, cats, and monkeys on top of that. The scale is staggering.

The obvious rejoinder is that animal research saves human lives, through the development of drugs and other treatments. While that’s certainly true, there are caveats. However useful animal research was in the past, it often falls short of expectations nowadays. One survey of 26 known human carcinogens found that fewer than half also caused cancer in rodents; you might as well flip a coin to get the same result.

Things are even worse with new medicines. In 2007, the U.S. Secretary of Health and Human Services admitted that “nine out of ten experimental drugs fail in clinical studies because we cannot accurately predict how they will behave in people based on laboratory and animal studies.” Such failures are in fact so common they’re almost cliché. How many times have we heard about some amazing therapy that miraculously stops cancer or Alzheimer’s disease in mice — only to watch it flop in human beings?

Perhaps this shouldn’t surprise us. Evolutionarily, rodents and humans diverged 70 million years ago, back when dinosaurs still ruled the Earth, and we have notably different physiologies. Penicillin is actually fatal to that proverbial lab animal, the guinea pig; had scientists initially tested this drug on them, it never would have made it to market. Given these facts, some critics of animal testing have been scathing. One called animal research “an internally self-consistent universe with little contact with medical reality.”

In the past few decades, there’s been a movement to cut back on the number of animals used in labs and find alternatives. Possible alternatives include running tests on human organs grown in dishes (organoids) or using computer programs to estimate the efficacy of new chemicals by comparing them to known compounds.

In all, life is vastly better for research animals today compared to the 1880s. But reports of abuse still pop up in labs around the world, and outré experiments (like monkey head transplants) have not ceased. The howls of Edison’s dogs continue to echo today.


Sam Kean is a New York Times bestselling author whose works include The Icepick Surgeon and The Disappearing Spoon. His writing has appeared in The Best American Science and Nature Writing.

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