The 6 scariest science experiments in history

The Dark Side of Human Experiments / Date: 04-12-2025

The image of mad scientists has always been explored in literature and the film industry. Some of these characters are simply eccentric and, even with all their quirks and unusual attitudes, they end up surprising everyone in a positive way. This is the case of the young Dexter, for example, to whom we have already dedicated an infographic .

But others tend to have a dark side, capable of creating true atrocities. The professionals on the list below may not have a bad character, but the methods they used to prove their theories and achieve their achievements seem to have come straight out of the most fantastical pages of fiction. So, get to know the six most frightening scientific experiments in history.

1. Executed by justice and science

John W. Deering was killed in 1938 during a scientific experiment. But don't worry: the explosion didn't happen by accident. The fact is that Deering had already been sentenced to death for murdering a man during a robbery, and so he agreed to have doctors monitor his heartbeat while he was being shot.

Thus, on October 30, 1938, the convict had his last meal and, the following morning (31), he went to serve his sentence. After having electrocardiogram sensors positioned on his wrist, Deering was shot by five gunmen paid by the city of Salt Lake City. The exam recorded a 4-second spasm in the prisoner's heart. A while later, the heart had another spasm. And the rhythm gradually slowed down, until it stopped completely 15.6 seconds after the victim was shot.

According to the doctors who conducted the experiment, the results could be useful to heart disease experts, as they clearly showed the effect of fear on human beings. Just for fun, Deering's heart rate went from 72 bpm to 180 bpm when he was strapped to the execution chair. Despite the condemned man's apparent calm, the average number of beats per minute remained high until the end of the experiment.

2. The mischief of turkeys

Martin Schein and Edgar Hale, both from the University of Pennsylvania, were intrigued by a very pertinent question that could not go unanswered: what would be the minimum stimulus necessary to excite a turkey to the point that it tries to copulate? And before you think something stupid, let me clarify: we are actually talking about the bird, the one that goes “gluglu” and ends up, inevitably, being served as a dish at the end of the year dinner.

As surprising as the scientists' doubts were, the results they found were as follows. Using a realistic model of a turkey, the researchers gradually removed parts of its body. Even without wings, feet and a tail, the model continued to be attractive to the bird, which tried to mate anyway.

Not content with that, Schein and Hale went one step further: they simply placed the turkey's head on a wooden stick, and even then the turkey showed great interest in it. In fact, the study concluded that the bird preferred the head on the stick to a headless body. Now, try not to think about that next Christmas.

3. The terrible two-headed dog

In 1954, Vladimir Demikhov shocked the world when he presented the results of his experiment: a surgically created dog with two heads. But the monstrosity didn't stop there. The scientist implanted not just the head, but the entire front part of a puppy into the neck of an adult German Shepherd. Journalists could hardly believe what they were seeing, especially when the two heads began drinking milk simultaneously.

The Soviet Union hailed Demikhov's feat as proof of the superiority of its doctors, and over the course of 15 years, the Russian created 20 two-headed dogs, none of which lived very long. The record lifespan was one month, as there was a high rejection rate of the grafted tissue.

But Demikhov did not perform these procedures out of sadism. The doctor was a pioneer in the study of vital organ transplants and wanted to one day perform heart and lung transplants on humans. But the person who ended up transplanting the first human heart, in 1967, was the South African Christian Barnard, who visited the Soviet's laboratory twice and considered Demikhov to be a teacher.

4. Monkey head transplant

As expected, Vladimir Demikhov's feat ended up irritating another superpower of the time, the United States. So, in an attempt to show that its surgeons were better, the American government funded Robert White in a series of experimental surgeries that resulted in the world's first monkey head transplant, on March 14, 1970.

It took White and his assistants hours to perform the surgery, which required some choreographed movements to be successful. And they succeeded: they removed the head of a monkey and implanted it in a new body. When the monkey woke up in its new body, it began following the surgeon with its eyes and showing signs of anger, making it clear that it did not like what had happened. Unfortunately, the guinea pig survived for only a day and a half, before dying from surgical complications.

Unlike what happened to Demikhov, Robert White was not treated as a hero by the American people. The public, frightened by the experiment, vehemently condemned White's feat. But this did not stop the doctor from continuing his studies, even suggesting that the same experiment be carried out on human heads, which, for better or worse, never happened. The surgeon died in September 2010.

5. Electrification of human bodies

In 1780, anatomy professor Luigi Galvani discovered that a little electricity caused the limbs of a dead frog to twitch. Other European scientists soon began to replicate the experiment. It wasn't long before they decided to do something a little more terrifying: shocking human corpses.

It was then that Giovani Aldini, grandson of Professor Galvani, went on tour throughout Europe presenting one of the strangest shows the world has ever seen. The peak of his performances came in 1803, when he applied the poles of a 120-volt battery to the body of an executed murderer.

When Aldini placed the electrical wires in the corpse's mouth and one of its ears, the dead man's jaw muscles twitched, and it was as if the former killer was in great pain. His left eye even opened, as if he were staring at his torturer. To top it off, Aldini placed the wires in the dead man's ear and rectum, causing the entire corpse to shake, as if it were coming back to life.

It is believed that it was one of these experiences that influenced Mary Shelley to write “Frankenstein”, an 1816 novel that became one of the most famous books in the world.

6. Experimenting with vomiting in the name of science

During the early 19th century, Dr. Stubbins Ffirth decided to go a little too far in proving his theory. Noting that yellow fever was very common in the summer and disappeared in the winter, Ffirth concluded that the disease was not contagious and was instead caused by a series of stimulating factors.

To prove his case, the Pennsylvania doctor needed to expose himself to yellow fever as much as possible and show that he had not been infected. So Ffirth made small cuts in his arm and poured the vomit and blood of the sick over them. The result: he did not get sick.