14. August Bier
German surgeon, August Bier was the first person to invent spinal anesthesia in 1898 thanks to mishaps with self-experimentation and using his assistant as a guinea pig. His treatment involved using a small dose of cocaine that would be injected into the cerebrospinal fluid that surrounds the spinal cord, which he felt was much more effective than the methods at the time.
In order to test his treatment, Bier let his assistant Hildebrandt administer the treatment, unfortunately he mixed up the equipment leaving Bier with a hole in his neck. This did not sway Bier, who then administered the treatment to Hildebrandt instead. Once he had been successfully treated, Bier hammered, burned and stabbed his assistant to test the anesthesia effects. He even went as far to pull out his pubic hair and crush his testicles. Of course, the next day this did not go over well with Hildebrandt and the two eventually had a falling out. Hildebrandt would go on to be one of Bier’s most outspoken critics. Honestly, can you blame him?