10 Crazy Things Scientists Used To Believe


With each advancement of science, our knowledge of this world and the worlds outside it is increasing by leaps and bounds. Today we take much scientific knowledge for granted. But actually, they are the results of centuries of interpretations and experiments. For a long time common people, physicians, and even scientists based their theories more on beliefs rather than on scientific proofs. Those theories might make us laugh today, but at one time they were an integral part of people’s life. Keep reading this list to discover 10 crazy things scientists used to believe in.

1. Prior to the germ theory of disease, doctors believed the “miasma” theory according to which disease was spread through poisonous air rising up from the ground as a result of decaying organic matter carried by wind from stagnant swamps and cemeteries.

Image credit: Sebastian Petrycy/wikimedia,  U.S. National Library of Medicine

For many centuries, doctors and scientists debated over the possible cause of diseases such as chlamydia, cholera. or the black death. One of the most widely accepted theories in those times was the “miasma” theory. According to this theory, these epidemics were caused by miasma, i.e., bad air, emanating from rotting organic matter.

Since the ancient times, the miasma theory was accepted in Europe, China, and Southeast Asia. Miasma, the poisonous vapor or mist, was thought to be filled with particles from decomposed matter. During the 1850s, the miasma theory was challenged by physicians such as John Snow and Filippo Pacini. The definitive end of this theory came after 1876 when Robert Koch proved that the bacterium Bacillus anthracis caused anthrax, and then the germ theory started gaining a foothold. (1,2,3)

2. Before the widespread acceptance of the theory of plate tectonics, scientists believed that there existed large, prehistoric, intercontinental “land bridges” spanning thousands of miles of deep ocean.

Image Credit: USGS/Wikimedia

At the present time, geologists and scientists all over the world agree to the fact that the surface of Earth is not a single, solid mass. It is rather made up of many plates that are residing and sliding on top of Earth’s mantle. But before the theory of plate tectonics came into existence, it was thought that the continents were joined through land bridges which are now submerged under water.

The theory of land bridges was formed when geologists noticed that some fossils and geological features of one continent matched with those of another even though both are separated by great oceans. They found fossils of many similar organisms and terrestrial plants in two or more continents. To explain such similarities, the orthodox science at that time put forward the theory that a long time ago land bridges, now sunken, connected these far-flung continents together. (12)

3. Prior to 1860s, doctors did not wash their hands before attending to patients, and the doctor that proposed medical professionals should wash their hands before handling patients was so mocked by his peers that he suffered from a nervous breakdown.

Image Credit: Welcome Collection

In 1865, a Hungarian physician, Ignaz Philipp Semmelweis, was committed to an asylum as he suffered a nervous breakdown. The reason: he suggested that doctors should wash their hands after examining a patient. In those times, the germ theory of disease was not widely accepted. Hence, doctors didn’t wash their hands after performing an autopsy and even after examining a patient. The bed linens and laboratory coats were not washed. Surgical instruments were cleaned only when they were put away for storage.

Also, in those times, it was a common notion that a gentleman’s hands are always clean. Since doctors were gentlemen, they refrained from washing their hands. So, when Semmelweis suggested that doctors should wash their hands, he was mocked and ridiculed. After his death, the germ theory came into existence, and by 1875, scrubbing of hands and sterilization of instruments were widely practiced. (1,2)

4. Mercury was once considered safe and used as a disinfectant, laxative, cure for syphilis, and even as a pill for immortality.

Image credit: Bionerd/WikimediaInternetarchivebookimages/Flickr

Today, we are well aware that mercury is extremely toxic and a harmful, environmental pollutant. But in earlier times, common people, as well as scientists and physicians, used this “liquid silver” extensively. They believed it to be a miraculous substance capable of eradicating most diseases. Its popularity can be understood by the fact that when in 210 BC a Chinese emperor, Qin Shi Huang Di, wanted to become immortal, he was given potion or pills containing mercury by his court scientist. It ultimately led to his death.

In the sixteenth century, mercury was extensively used in medicine. For the next four centuries, mercuric compounds were an essential ingredient in drugs in both Asian and European pharmacopeias. As a result, more people died of mercury poisoning than from the maladies they were actually suffering. Even in the 1990s, mercury was used as a spermicide. It is still used in dental amalgams, cosmetics, saline solutions, and eye drops. (1,2,3,4)

5. Before the invention of railways, it was believed that people would suffocate if they traveled faster than 30 mph as they would not be able to breathe due to the surrounding air rushing past them.

Image Credit: Pixabay

Can you imagine a world without trains? Probably not. It is one of the cheapest and extensively used modes of land transportation. But before the invention of railways, people had very negative and rather funny notions about anything that travels faster than 30 mph. A train journey was believed to be harmful to the brain. It was believed that the jarring motion of train could drive a normal person insane and the noise could shatter nerves.

During the 1860s and ’70s, many cases of “railway madmen” were reported. The media took up the topic, and bizarre behavior of passengers on trains became common news. Physicians and psychologists wrote extensively about this topic. Even medical journals contained articles that contained information as to how railway madmen can be detected. Eventually, the railway-madmen hype ran out and the problem faded out as inexplicably as it had appeared. (1,2)

6. Prior to discovering oxygen and its role in combustion, scientists proposed that a substance called “phlogiston” did exactly the opposite—was released by burning fuel, squelched fire when it saturated airtight spaces, and was even expelled from the body through breathing.

Image credit: Mariiapulido/Wikimedia

More than 100 years ago when oxygen hadn’t been discovered, scientists and philosophers believed that fire was an element. All combustible objects contained a fire-like element which was released into the atmosphere during combustion. This element was called “phlogiston.” The phlogiston theory was first stated by Johann Joachim Becher in 1667. This theory was used to understand processes such as combustion and rusting.

Until the 1770s, the phlogiston theory was the most widely accepted theory. Its popularity can be understood by the fact that when Joseph Priestley discovered oxygen in 1774, he called it “dephlogisticated air.” (12)

7. Before the concept of vacuum came into existence, physicists believed that there was no empty space in the universe, and light traveled through a medium called “aether.” It was considered a fifth element along with earth, wind, fire, and water.

Image credit: Cronholm144/Wikimedia

According to the ancient and medieval science, the space above earth’s terrestrial sphere was filled with a material called “aether”, also known as “quintessence” and now referred to as “ether.” It was believed to fill the universe and act as a medium for the propagation of light. Until the 19th century, various physicists conducted numerous experiments but couldn’t find any physical evidence that could prove the existence of ether. Its end came after Einstein’s “Theory of Relativity” was published as it solved many theoretical problems related to ether. Since then, ether has been considered to be non-existent. (1,2,3)

8. In the 19th and early 20th centuries, benzene was used as an after-shave because it smelled nice. Also, it is one of the best organic solvents, so organic chemists used to wash their hands with benzene even though it is actually highly carcinogenic.

Image credit: RedditHaltopub/Wikimedia

In the days gone by, scientists didn’t know that benzene is carcinogenic (can cause cancer) in humans. That’s why it was used in various ways. Benzene was used as an after-shave lotion in the 19th and early 20th century. In 1903, benzene became popular in industries as it was used to decaffeinate coffee. Before the 1920s, it was used as an industrial solvent.

Historically, benzene was a significant component of many consumer products such as rubber cement, paint strippers, spot removers, and liquid wrench. It was even used by chemists to wash their hands. But, as the toxicity of benzene became obvious, its use was slowly discontinued. (12)

9. Until recently, it was a popular scientific belief that different sections of your tongue react to different tastes.

Image credit: MesserWoland/Wikimedia

Almost everyone who had attended their biology class had at one time or another seen the tongue diagram, also known as the “taste map.” It contains the image of a pink tongue with regions marked for various tastes. It shows that there are particular regions in our tongue which can detect a particular taste only. In reality, the tongue diagram is completely wrong. Chemosensory scientists have debunked the myth, yet it is still taught in some schools.

The tongue diagram originated from a paper published in 1901 by a German scientist, David P Hanig. He found that different parts of the tongue have a lower threshold for perceiving certain tastes. But the differences are extremely minute. The diagram sketched by him was the artistic interpretation of his measurements. The diagram was wrongly interpreted and later accepted by the world as the taste map. (123)

10. Up until the mid-19th century, it was commonly believed that placing dirty underwear in a bucket with wheat grains would “generate” mice. This was called “spontaneous generation,” the idea that life could be created from nonliving objects.

Image credit: Fsk-goto/Wikiemdia

Many centuries ago, it was a common “knowledge” that non-living objects can give rise to living organisms by “spontaneous generation.” This theory materialized from daily observations of people and scientists. Farmers noticed that an otherwise empty barn would be brimming with rats and mice when grains were stored in it. So, they thought that rats and mice generate from grains. Similar observations gave rise to beliefs such as rotten meat creates maggots and flies, and muddy soil gave rise to frogs, worms beetles etc.

The theory of spontaneous generation held its ground firmly until the 18th century. After that, various experiments by scientists suggested that higher organisms could not be produced by nonliving objects. The end of this theory came later in the 19th century when Louis Pasteur showed the world that microorganisms such as bacteria can reproduce. (12)

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