[ ♪ INTRO ] 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. [ ♪ OUTRO ]
