All great discoveries have one thing in common: they all started as theories. Doctors and scientists all over the world are constantly putting their time, resources and efforts into coming up with and testing out theories. It comes as no shock that there are wrong (and some quite insane) theories floating around in those history books.

Stubbins Ffirth was an American trainee doctor. Stubbins was born in 1784 and is most recognized for his unusual theory about what caused the spike of yellow fever during summers.

Ffirth theorized that since there was a drop in cases of yellow fever during winter, the heat and stress of summer must be the cause of the disease. This would mean that the disease was not contagious. The theory seemed harmless enough to begin with, it wasn’t until Stubbins tried to prove his theory that things became interesting.

Ffirth was determined to prove that the disease wasn’t contagious. Ffirth experimented with the vomit of people who were ill with yellow fever. He would make small incisions on his body and smear the vomit onto the cuts. Ffirth did not get sick from this first experiment which led him to take even more drastic measures. Ffirth then tried to inhale the fumes of the vomit which yet again did not get him sick.

His final and most desperate attempt to prove that it would be impossible to contract the disease was to actually ingest the vomit. When he did not get sick, Ffirth thought this was solid evidence to prove his theory was correct. It wasn’t discovered until later on that Ffirth had been using the vomit of late-stage patients who were no longer contagious with yellow fever.

The cause of yellow fever was later discovered by Carlos Finlay, a Cuban scientist, who discovered that mosquitoes carried the deadly disease. Unfortunately for Ffirth this discovery didn’t come until six years after his death.

During the second half of the 19th century Dr. Silas Weir Mitchell was using a new form of treatment that would supposedly cure those who were seen as hysterical. This treatment was exclusively used for women.

Mitchell’s treatment involved blocking out all the senses of the women who were seen as ill. This included no talking and no movement. Although Mitchell didn’t just want the women to stop all physical movements he also insisted that the women didn’t read, think or even use their imagination during the supposed treatment.

Mitchell’s suggested this insane treatment to women who were seen as ill in any way. This of course led women who were looking to detach themselves from the patriarchal society to be shocked by such a suggestion. Thankfully Dr. Mitchell’s theory and proposed solution didn’t seem to catch on.

Dr. Galen, a Roman doctor, believed that when a person consumed food that it ultimately turned into blood. Galen knew that food first had to be digested but after that he believed that is was taken to the liver and ultimately made into blood.

Galen had produced many other correct theories throughout his time, but this theory definitely didn’t make his top 10 greatest theories list. Galen wasn’t entirely to blame since he had to come up with these theories without being able to dissect and learn from the human body. Dissection during the time was prohibited by the Roman Empire which led to a lack of understanding about the body. This produced the incorrect theory about blood production.

This theory of blood production in the liver actually didn’t come into the hot seat until the 16th century when Andreas Vesalius, a Flemish doctor, began to question the validity of Galen’s theory. It was discovered long after Galen was gone that blood cells were produced from bone marrow.

In today’s society our doctors and scientists are well-equipped with better tools and education to help them produce their theories. Thankfully the days of boiling vomit are gone and the medical field is constantly changing and improving.