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The role of a scientist is to make observations, do experiments, and form hypotheses about how and why things happen.
Sometimes, thousands of years of evidence can support ideas, like the geometry of the Earth.
But many people have struggled to understand things in the past and present for a lot of
reasons — from preconceived notions about a field of research, to technological limitations.
So it’s fun to look back at whose ideas were ruled out by their contemporaries, even
though we now know these 5 scientists were onto something.
Born in 1862, William B. Coley was a bone cancer surgeon in New York.
He had seen many a patient die even after a tumor was removed or an entire limb was amputated.
Physicians knew that rapidly-dividing cancer cells could spread.
But the mechanics behind metastasis, where cells hitch a ride in blood or other fluid
and start growing somewhere else, weren’t well understood.
So Coley was determined to find a more effective way to stop cancer from taking lives.
He began looking through records at the New York Hospital, where he worked.
And he came across a patient from 1883, who had a cancerous tumor in his neck that couldn’t be removed through surgery.
That tumor seemed to vanish after the patient developed a skin infection called erysipelas,
usually caused by Streptococcal bacteria.
Coley tracked that patient down and found that, 7 years later, the tumor hadn’t regrown.
And he found dozens of papers describing infections somehow reducing cancerous cells.
So in 1891, Coley injected Streptococcal bacteria into a patient dying of bone cancer, who made
what seemed like a miraculous recovery.
Now, keep in mind that the ethics of many medical treatments at the time were super
questionable or nonexistent.
And this was no exception.
After this first success, Coley kept trying.
And while his next few patients had tumor shrinkage, they died from bacterial infection.
Coley published those findings.
And then he tried to make his technique less dangerous using a combination of a heat-killed
Strep species with another bacterium.
The mixture became generally known as Coley’s Toxin.
He treated nearly 1,000 cancer patients over the next 40 years with it, and published more
than 150 papers about his work.
Although Coley was often reportedly successful, his tests were inconsistent.
For instance, he switched up the bacteria he injected and the injection sites, and he
didn’t reliably follow up with treated patients.
Needless to say, this led to a great deal of skepticism from other physicians.
Which totally makes sense.
In 1894, the Journal of the American Medical Association released a statement that deemed
Coley’s work a failure.
It reported that “no well-authenticated case of recovery” had been reported because
of toxic injections.
But Coley continued to practice with his toxins until the end of his career in 1933.
And by then, other doctors had started using them too.
Even Journal of the American Medical Association changed its tune.
In 1934, they agreed that these toxins may have some medical value in treating persistent
cancer.
Once radiation and chemotherapy came around in the mid-1900s, Coley’s Toxin all but
disappeared.
In 1962, the FDA refused to back it as a legitimate way to treat cancer.
It wasn’t until the 1980s that researchers started looking into the idea of cancer immunotherapy.
We started to understand ways the immune system could be activated to recognize and kill rapidly
dividing cancer cells, and now scientists are working on all kinds of different treatments.
Just... not with a bunch of questionably harmful bacteria, and with patients’ consent.
[2.
Francis Peyton Rous]
From 1909 to 1911, scientist Francis Peyton Rous made what is now thought of as a major
discovery in the field of virology.
At the time, though, his work didn’t gain much momentum.
Rous was working at The Rockefeller Institute in New York, when a woman came in carrying
a hen with a massive tumor.
Apparently that’s the kind of thing that just… happened when you were doing cancer
research back then?
Scientists were already starting to think that cancer could be transmitted between living
things, based on observations of cervical cancer in humans, lung cancer in sheep, and
avian leukemia.
These ideas weren’t given too much attention at the time.
But Rous was curious to see if material from the hen’s tumor could cause cancer in a
healthy chicken.
And it did.
To learn more, Rous passed more tumor material through a filter that strained out bacteria.
And he found the same thing: When he injected a healthy chicken with the filtered tumor
goop, it developed a tumor.
At the time, this was enough evidence to rule out bacteria as the perpetrator.
So it led Rous to hypothesize that a virus must be responsible.
Rous kept at this research, and found that other chicken tumors were transmissible too.
So this hen wasn’t just a strange case study.
Unfortunately, the scientific community’s lack of interest meant that this discovery
didn’t really make a splash.
And there were bigger fish to fry: the U.S. entered World War I in 1917 and Rous shifted
his focus to blood transfusions and making blood banks to help injured soldiers.
Over a decade after the war, Rous’s research into a connection between viruses and cancer
was reinvigorated.
And he was part of a team that discovered a virus that caused benign tumors in rabbits.
Still, progress was slow until the 1950s, when an enzyme called reverse transcriptase
was discovered by researchers.
Reverse transcriptase helps convert RNA carried by some viruses into DNA that can get into
the host’s genome to churn out more viruses.
Like how HIV works.
With more molecular mechanisms coming to light, viral oncology was picking up speed.
Scientists were studying how viruses can cause cancer, and discovering things like oncogenes
— the genes that can cause a normal cell to become cancerous.
And in 1966, at 87 years old, Rous was awarded the Nobel Prize in Physiology or Medicine,
marking the longest time between a discovery and a Nobel Prize being awarded.
[3.
Ignaz Semmelweis] Ignaz Semmelweis was a Hungarian-born physician
who began practicing in Vienna in 1844.
Semmelweis worked in obstetrics, delivering babies and working with parents before and
after birth.
And he observed that people who had midwives deliver their babies only had a mortality
rate of 2%, compared to the much higher 13–18% when physicians and medical students did it.
Those deaths were largely due to puerperal fever, a dangerous bacterial infection of
the reproductive tract, which set in one day to just over a week after giving birth.
Giving birth can cause quite a bit of bodily trauma, which makes people highly prone to
infection.
And this was back in the day when handling corpses and doing autopsies was routine for
medical students and physicians.
So Semmelweis hypothesized that people not washing their hands between handling corpses
and delivering babies caused this sickness and death.
Semmelweis instituted a hand washing policy for medical students and physicians with chloride
of lime solution, which killed bacteria and was used as a general disinfectant.
After that, the mortality rate dramatically fell to match when the midwives delivered
babies.
And eventually, Semmelweis disinfected the medical tools and even more people lived.
But Semmelweis’s superior was not a fan of his ideas.
He believed that the hospital’s new ventilation system was responsible for this lack of death.
That fit the popular miasma theory of disease at the time: that diseases were caused by
“bad air.”
So Semmelweis basically got shunned from the hospital in 1849, went back to Budapest, and
became head of obstetrics at a hospital there.
He instated hand washing for doctors and nurses and, just like in Vienna, this lowered mortality
rates.
In 1861, Semmelweis wrote a book about puerperal fever and his ideas about disinfectants, but
the medical community didn’t bat an eye.
And a few years later, he died in a mental institution.
Presumably, of frustration.
It took researchers like Joseph Lister, Louis Pasteur, and Robert Koch studying germ theory,
the idea that microbes like bacteria can cause disease, to have these ideas taken seriously.
So even though recognition came too late, Semmelweis was still considered a “savior
of mothers” because of his strong belief in disinfectants.
And he’s still being honored today.
Including by us, thank you.
[4.
Gregor Mendel]
Gregor Mendel was born in 1822.
He was an Augustinian friar living in what’s now the Czech Republic.
Mendel is best known for his experiments with pea plants.
He bred them and studied seven main traits, from plant height and flower position to seed
shape and color.
He didn’t know it at the time, but this was a lucky pick.
These pea plant traits were only determined by two alleles — or variations — of one
gene.
Usually genetics are much more complicated than that.
But because they were pretty straightforward, Mendel noticed some clear patterns.
For example, a tall pea plant bred with a short pea plant would produce tall offspring.
But if he bred those offspring, around a quarter of the next generation was short again.
Words like “allele,” and “gene” didn’t exist yet because these experiments were pretty
radical at the time.
So Mendel called these things that influenced traits factors.
Each parent had two of them, and passed one down at random.
And he came up with recessive and dominant to describe how some traits outweighed others
in offspring.
Plus, he proposed that different traits, like seed color or plant height, are controlled
by different genes that are passed down independently.
All these ideas were wildly different from the understanding at the time.
Scientists were all-in on blending inheritance, which is the idea that offspring are an average
of their parents.
Like, if one parent has dark brown hair and the other has blonde hair, their child will
have light brown hair.
So even though Mendel published his work on genetic inheritance in 1866, he didn’t get
recognition for it and just sort of… went on with his life.
Around 1900, over a decade after Mendel’s death, three scientists were studying plants
and discovered Mendel’s then-obscure paper and hypotheses along the way.
Two also worked with peas, one worked with evening primrose.
And they all saw Mendel’s work as validation for their own.
In the early 1900s, our understanding of cells and chromosomes sped forward.
And eventually Mendel became known as the “father of modern genetics.”
[5.
Alfred Wegener]
In the early 1900s, German geophysicist, meteorologist, and polar researcher Alfred Wegener proposed
the idea of continental displacement, now called continental drift.
Wegener came across a paper in 1911 that talked about identical plant and animal fossils on
either side of the Atlantic ocean.
At the time, things like that were explained by land bridges that supposedly connected
continents in the past and then sank into the ocean.
But Wegener did not buy it.
He also noticed that maps of coastlines of Africa and South America seemed to line up,
and so did geological features like mountain ranges.
There were also other weird fossils that suggested some sort of radical change, like tropical
fern fossils discovered on an Arctic island.
And all those observations planted a seed of an idea: maybe these continents were once
joined together but drifted apart.
In 1915, Wegener’s book, The Origin of Continents and Oceans, was published.
In it, he coined the term Urkontinent, meaning “original continent” in German.
This became Pangea, roughly meaning “all the Earth” in Greek.
Although Wegener wasn’t the first to suggest that continents were once connected, he did
so with more evidence than before.
But he was met with resistance, because there wasn’t enough.
One major flaw was that he couldn’t explain how the continents moved.
Wegener believed they just sort of plowed through the ocean floor.
Which, by the way, we now know was very very wrong.
So I guess you can’t really blame his contemporaries for being skeptical.
In the wake of this “meh” reaction, Wegener went back to doing more meteorology research
and died at a young age on an expedition to Greenland.
So he wasn’t around in the 1950s and 60s, when researchers began making more discoveries
about the ocean floor, Earth’s crust, and phenomena like earthquakes and volcanoes.
The idea of plate tectonics began to take shape, and Wegener’s hypothesis about continental
drift didn’t sound so controversial after all.
So science isn’t a straightforward path to answers about ourselves or the universe,
and sometimes hypotheses hold up decades after they were dismissed.
Thanks for learning about these scientists here with us on SciShow, and thanks especially
to our patreons on Patreon for helping us make these videos.
So if you want to join our community and support free education online, you can go to patreon.com/scishow.
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