To put it in the illustrious words of Bill Nye, “science rules.” But sometimes scientists are so eager to prove their hypothesis that they go a little crazy with their methods. Just bear in mind as you read this that many of the scientists on this list didn’t have to submit their research plans to any sort of ethics committee for review before proceeding, so it’s pretty unlikely you’d find any mad scientists like these roaming the halls of research buildings and university campuses today.

**Warning: Some of these “experiments” are pretty gruesome**

12. Paracelsus (1493 – 1541)

Paracelsus was a 16th-century, Swiss-German scientist who made a number of advancements in the fields of biology, chemistry and medicine. Many professionals accept him as the founder of toxicology for correctly concluding that toxic substances, in small doeses, could be used beneficially. But even though his mind for medicine was centuries ahead of its time, he was still a bit of an occultist and performed his fair share of bizarre personal experiments.

In 1537, Paracelsus wrote a treatise addressed to his brother where he described some of the alchemical secrets he had acquired over the years. Of particular note was his recipe for making a homunculus (a small humanoid created through alchemy). According to Paracelsus’ instructions, first you take some sperm and let it decay in a pile of horse manure for about 40 days. By that point, the sperm should come to life and begin resembling a tiny transparent human without a fully-formed body. Then, all you need to do is keep it in horse manure and feed it human blood every day. After 40 weeks of blood meals, you should have yourself a genuine homunculus.

11. Johann Conrad Dippel (1673 – 1734)

If a person’s birthplace has any bearing on their adult profession, then Johann Conrad Dippel was always destined to be a mad scientist. Born at Castle Frankenstein in Germany, Dippel was a 17th century physician and theologian. Like any good mad scientist, he liked to dabble in alchemy and was interested in finding the perfect “cure-all” remedy. Eventually, his efforts resulted in the creation of “Dippel’s oil,” a putrid concoction made by distilling animal bones. Dippel claimed it could be used for a wide range of ailments.

There were a lot of rumors surrounding Dippel’s work. The horrible stench that often came from his lab made people think he was experimenting with cadavers and trying to bring them back to life. Perhaps he really was the inspiration for Mary Shelley’s Frankenstein.

10. Giovanni Aldini (1762 – 1834)

Speaking of people who might have inspired the novel Frankenstein, here’s another candidate. Giovanni Aldini was a 19th century physicist who traveled Europe with what can best be described as a freak show circus of science. During one show in London in 1802, Aldini electrocuted the severed heads and bodies of dogs, horses, sheep and cows with high-powered batteries. The dead animals began to move and twitch as if they were alive, prompting one reporter in the audience to refer to Aldini’s spectacle as “Satan’s Puppet Show.” But Aldini’s most famous experiment came the next year, in 1803, when he was given the body of a hanged criminal who had been executed for the murder of his wife and child. After applying conducting rods to the dead man’s rectum, the corpse began to punch and kick the air violently. Rods applied to the face also seemed to make it come alive. When one of the eyes popped open several people in the audience feared the man had come back to life. Had that been the case, he would have, of course, been immediately executed again.

9. Andrew Ure (1778 – 1857)

While Giovanni Aldini became famous for electrocuting of the body of a deceased criminal and making it appear alive, it was a Scottish doctor named Andrew Ure who took that experiment to the next level. Like Aldini, Ure was given the body of a hanged killer. However, Ure believed that electricity could be used to actually bring the corpse back to life. After inserting rods into different parts of the dead man’s body and sending a current through them, the corpse began to convulse violently. And by stimulating the supraorbital nerve, he was able to make the cadaver’s face display a range of emotions including anger, horror, despair, anguish, and most disturbing of all hideous, contorted smiles. The expressions scared viewers so badly that even doctors who were known to have strong stomachs passed out at the sight.

In the end, Ure didn’t succeed in bringing the dead back to life. He believed the reason for his failure was because the body had been drained of blood which prevented the heart from sustaining a pulse when it was shocked.

8. Barry Marshall (1951 – Present)

In the 1980s, Barry Marshall, an Australian doctor, was conducting research on bacteria to support his hypothesis that certain bacteria are linked to ailments like ulcers and gastric cancer. Marshall felt certain that bacteria caused ulcers because he had watched his patients make full recoveries after going through antibiotic therapy. But when he tried to publish his findings, the medical community told him there was just no way that bacteria could survive in stomach acid. So, to prove them wrong, Marshall ingested some of the bacteria he was studying. In just days, the crippling symptoms of gastroenteritis began to kick in, confirming his assumptions. To save himself, Marshall then biopsied his own stomach, isolated the bacteria, and took the necessary antibiotics to counteract the effects.

In 2005, Marshall and his collaborator Robin Warren were awarded the Nobel Prize in Medicine for their discovery.

7. Werner Forssmann (1904 – 1979)

In 1929, heart surgery was still in its infancy and many doctors experienced great difficulty when performing invasive cardiac surgery on patients. Werner Forssmann proposed that he could reach the heart by inserting a hollow tube through his patients’ veins. However, other physicians in Germany told him that his procedure would surely kill anyone who underwent it. Frossmann strongly disagreed and planned to test his method on himself to prove it could be done.

Concerned for his safety, a nurse agreed to secretly bring Forssmann sterile medical supplies as long as he promised to perform the procedure on her instead of on himself. Forssmann agreed and anesthetized his nurse. But instead of using her as the subject, he made an incision in his own arm and blindly guided the catheter into his heart. Still very much alive, Forssmann then walked down to the X-Ray lab so he could show his handiwork.

Years later, in 1956, Forssmann would receive the Nobel Prize in Medicine for his accomplishments.

6. Alexander Bogdanov (1873 – 1928)

Dedicating much of his career to the search for eternal youth, Alexander Bogdanov’s research focused primarily on the study of blood tissue. After becoming convinced that blood transfusions could be used to rejuvenate the human body, he founded the Institute of Blood Transfusion in 1926. According to him, blood was the key to a longer life and perhaps even immortality.

Bogdanov used himself as a test subject and, after multiple transfusions, he claimed that his balding had stopped and his eyesight had improved. Ironically, rather than extending his life, a blood transfusion is actually what resulted in Bogdanov’s death. In 1928, he died of a hemolytic transfusion reaction after unwittingly transfusing himself with blood from a person who had contracted malaria.

5. Jose Delgado (1915 – 2011)

Dr. Jose Delgado was a Spanish professor of physiology at Yale University who was famous for investigating the possibility of mind control through electrical stimulation of certain regions in the brain. To conduct his research, Delgado invented the stimoceiver, a device which acted as a wireless brain stimulator/monitor when implanted in the head of a test subject. The stimoceiver worked by sending electrical signals to evoke responses in the brain. Delgado conducted his first tests on cats, but later moved on to monkeys and eventually human beings.

Through the stimoceiver, Delgado found he could basically control behavior and stimulate any emotion he wanted, even elicit strange visions. To prove his device worked flawlessly, Delgado went out and stood in front of an angry charging bull. Having previously installed a stimoceiver in its head, once activated the ferocious animal stopped in its tracks and calmed right down.

When human test subjects were concerned, his device only impacted people’s aggression. However, he kept looking for a way to achieve genuine mind control, and once publicly shared his disturbing vision of the future, stating: “We must electronically control the brain. Someday armies and generals will be controlled by electric stimulation of the brain.”

4. Jack Parsons (1914 – 1952)

As an engineer, chemist, inventor and co-founder of the Jet Propulsion Laboratory (JPL), Jack Parsons was a brilliant rocket scientist. He created the very first rocket engine and helped pioneer the advancement of both liquid-fuel and solid-fuel rockets. However, the truth of the Caltech researcher’s bizarre personal life is well-documented. In 1939, Parsons converted to Thelema, which was a sort of spiritual philosophy on life established by English occultist Aleister Crowley. Parsons became one of Crowley’s most devoted students, even to the point that he would invoke the name of the Greek god Pan before every rocket test. Later, he joined up with Scientology founder L. Ron Hubbard and together the two engaged in many strange practices including something called the Babalon Working, in which a series of magic rituals were performed over several months in an attempt to summon a living goddess. Too bad Parsons didn’t live long enough to see Hubbard grow to become a spiritual leader in his own right. He was inadvertently killed in an explosion caused by some volatile chemicals he kept lying around.

3. Stubbins Ffirth (1784 – 1820)

In the early 1800s a doctor-in-training named Stubbins Ffirth formulated the hypothesis that yellow fever was not an infectious disease. Ffirth came from Philadelphia, which had recently fallen victim to a yellow fever epidemic, and noticed that yellow fever cases were much more prevalent in the summer than in the winter. He concluded that the reason for the discrepancy must be because the disease was not contagious. In order to prove his assumption, he collected saliva, sweat, blood, urine and vomit from a number of yellow fever patients. Ffirth then proceeded to excessively expose himself to these fluids by pouring them into open wounds, rubbing them in his eyes, even drinking some of them straight. Throughout all of this, he stayed perfectly healthy and he took this as evidence to support his hypothesis. Unfortunately, it was eventually discovered that the patients who supplied him with all of those bodily fluids were actually late-stage and no longer contagious. It was later discovered that yellow fever must be injected directly into the bloodstream, typically through a mosquito bite, in order to be contracted. The reason why the disease is more prevalent in the summer months is because there are generally more mosquitos around at that time.

2. Ilya Ivanov (1870 – 1932)

Ilya Ivanov was a Russian biologist whose work was primarily devoted to artificial insemination and the creation of interspecies hybrids. In the 1920s, the Soviet government granted Ivanov permission to leave the country for the express purpose of breeding hybrid ape-humans. While in Paris, he grafted a woman’s ovary into a chimp named Nora and tried to fertilize her with human sperm. He then travelled to Africa and inseminated three chimps with some more human sperm. But when none of the chimps became pregnant, he altered his approach and began looking for Soviet women who might be willing to be inseminated with chimpanzee sperm. Amazingly, he found several volunteers, but, unfortunately for the Bolsheviks hoping to raise a slave army of ape-men, a Stalinist removal of scientists resulted in Ivanov being sent away to Kazakhstan where he died two years after his arrival.

1. Sergei Brukhonenko (1890 – 1960)

A Soviet scientist during the Stalin era, Dr. Brukhonenko is credited as the inventor of the first primitive heart-lung machine, what he referred to as the autojektor. While the machine did prove invaluable in performing the first Soviet open-heart surgery, Brukhonenko would use it primarily for a number of grisly experiments involving dogs. Essentially, by using the autojektor, Brukhonenko was able to keep the decapitated heads of dogs alive.

In 1928, he displayed this amazing technique to the public. To prove it was real, he banged a hammer on the table. The severed dog head flinched. When a bright light was directed in its eyes, the eyes blinked. And when it was fed a piece of cheese, the remnant promptly dropped out of the esophageal tube, much to the displeasure of the repulsed onlookers.

Though his experiments were undoubtedly macabre, all of Brukhonenko’s research was very well-documented, resulting in him posthumously being awarded the Lenin Prize—one of the most prestigious prizes of the Soviet Union.