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  • Have you ever saved someone’s life?

  • Maybe youve pulled a kid out of the street just in time, or fished a friend out of the

  • river, or did the Heimlich maneuver on the guy sitting next to you at the deli.

  • There’s a small group of people in history -- let’s just call them what they werenerds

  • whose scientific contributions have saved -- not that it’s a contest -- like, hundreds

  • of millions, if not billions, of people over time.

  • Including you, probably.

  • Now, this isn’t a comprehensive list or anything. Frankly, history is full of life-saving,

  • world-changing scientists. We just picked three of them.

  • And it’s important to remember that science is both collaborative and cumulative -- researchers

  • work with a whole team of people, and build on the work of those who came before them.

  • No scientist is an island.

  • But these are people who spearheaded both simple and revolutionary discoveries, from

  • proving that germs exist, to convincing doctors to start washing their hands, to creating

  • vaccines to stop common diseases.

  • First up, the guy whose name youll find on nearly every gallon of milk at the grocery

  • store: Louis Pasteur, the founder of germ theory and the father of microbiology.

  • Born in rural France in 1822, as a kid Pasteur was more interested in art than science, earning

  • a Bachelor of Arts before turning his focus to chemistry and physics.

  • He liked the idea of putting science to practical use in industry, and some of his early work

  • focused on figuring out how to better manufacture wine.

  • Hey, it was France.

  • Of course, people had been making alcoholic beverages since practically forever, but it

  • was Pasteur who gave us our modern understanding of the fermentation process -- he showed that

  • it’s the action of living, multiplying microorganisms, specifically yeast, that turns sugar into booze.

  • That might be common knowledge today, but back then, people didn’t know much -- if

  • anything -- about microbes.

  • There had been some speculation about what we now call germ theory -- the idea that microorganisms

  • might cause some diseases and make food spoil.

  • But the prevailing scientific theory of the time was something called spontaneous generation,

  • the notion that some organisms just sort of appeared out of thin air, or came to life

  • from decaying organic matter.

  • I’m not kidding, for a long time people thought baby mice came out of decaying hay,

  • and maggots were born from rotting meat.

  • Even after those specific things were disproven, people still believed that spontaneous generation

  • was a thing under certain circumstances.

  • But not Louis.

  • Building on the work of an 18th-century Italian physiologist named Lazzaro Spallanzani and

  • others, Pasteur conducted what ended up being one of the most important experiments of all time.

  • He boiled some broth in swan-necked flask, effectively sterilizing it -- so there were

  • definitely no breeding bacteria or anything.

  • The container allowed filtered air to enter the flask, but would catch any microbes in

  • the bend of the neck.

  • Then he waited, and nothing happened -- the broth never spoiled, meaning microbes weren’t

  • just appearing out of thin air.

  • But, if he tipped the glass so that the broth touched that filtering point in the neck that

  • was catching all the microbes from the incoming air, the broth quickly began to go bad.

  • That one simple experiment showed that life didn’t just spontaneously appear out of

  • nothing, but there were microbes in the air all around us.

  • Basically: he proved that germ theory was real.

  • With his new-found understanding of microbes in hand, Pasteur hit the bottles again, experimenting

  • with techniques to keep wine and milk from spoiling.

  • Then, in 1862, he found that heating up wine without actually boiling it would still kill

  • bacteria and keep it from spoiling.

  • That’s the process we now call pasteurization, and it’s still used today to protect and

  • preserve a number of foods, like milk and other dairy products.

  • By this point, Pasteur was in his mid-forties, and he wasn’t doing too well, health-wise.

  • He had a stroke and ended up partially paralyzed.

  • Even so, he continued his experiments, and went on to invent the first laboratory-developed

  • vaccine, for chicken cholera.

  • He then went on to create vaccines for more diseases, like anthrax and rabies.

  • The English doctor Edward Jenner, who died about a month after Pasteur was born, had

  • already discovered the smallpox vaccine in the late 1790s.

  • But it wasn’t until Pasteur proved germ theory that people really began to understand

  • how viruses and bacteria worked -- and with it, the real science behind vaccination.

  • You really can’t oversell the importance of getting the world on board with the idea

  • that microbes can spread, causing infection and disease, so the next time you crack open

  • a nice bottle of wine, don’t forget to raise a glass to Pasteur.

  • In fact, Pasteur greatly influenced our next legendary lifesaver, the British surgeon who

  • completely transformed surgical practices -- or, as I like to think of him, the guy

  • who finally got doctors to wash their hands.

  • Joseph Lister started life in Essex, England in 1827.

  • He was born into a wealthy Quaker family, and his father was an amateur scientist who

  • helped design microscope lenses in his spare time.

  • Lister was interested in science from a young age, and by college knew he wanted to both

  • work as a surgeon, and do research to help improve medical knowledge in general.

  • Which, as it turns out, was desperately needed at the time.

  • Let me paint a little picture for you:

  • Youre living in Europe in the mid 1800s. You fall off a ladder and break your leg.

  • Your friends throw you on a cart and wheel you to the hospital. The doctor says they

  • have to operate, and you don’t get any anesthesia because it’s not really a thing yet.

  • The surgeon walks in with dirty hands, unsterilized equipment, and an apron he likes to keep stained

  • and bloodied for the street cred.

  • You pass out from the pain, and when you wake up, your chances of surviving the coming infection

  • are less than 50-50 on a good day, in a decent hospital.

  • That’s the world Lister walked into after finishing his doctorate in the early 1850s.

  • But don’t be too hard on the surgeons -- this was before Pasteur proved germ theory, and

  • the common belief was that there wasn’t much they could do, since some wounds just

  • spontaneously generated infections.

  • But Lister wondered if there actually was a way to prevent those infections.

  • He started noticing that patients with simple fractures -- where a broken bone didn’t

  • pierce the skin -- were far more likely to recover than those with an open wound exposed

  • to the air.

  • This suggested that rather than springing from the wound itself, infection must somehow

  • get in from the outside, and he started washing his hands and clothes before operating.

  • Around that time, he became a professor of surgery in Glasgow and read about Pasteur’s

  • groundbreaking work on germ theory.

  • It made a lot of sense to Lister.

  • He figured that if outside germs were infecting wounds, then killing those germs should -- in

  • theory -- prevent infection.

  • Now, Pasteur stopped wine and milk from spoiling by heating them up, but it’s a lot harder

  • to do that to human flesh.

  • So Lister knew he needed to find the right chemical disinfectant.

  • He chose carbolic acid, otherwise known as phenol, which is a kind of acid that’s extracted

  • from coal tar. At the time, it was being used to disinfect sewers.

  • And in 1865, Lister began experimenting with a diluted form of phenol, using it to sterilize

  • his hands, instruments, wounds, and bandages. He even sprayed it into the surrounding air.

  • After collecting more than year’s worth of data, he published a paper explaining his

  • new antiseptic technique -- one that had led to a dramatic drop in post-operative patient deaths.

  • But, like so many discoveries, his new protocol was slow to gain traction -- some doctors

  • thought it was too slow and expensive, or tried it but didn’t clean properly, so it

  • didn’t work as well.

  • Others still just didn’t believe in germs.

  • But by 1880, after more than ten years of incredible results, his antiseptic principle

  • was nearly universally accepted.

  • Lister continued to improve surgical practices throughout his career -- for example, he introduced

  • stitches made from sterilized catgut, which would dissolve instead of having to be pulled out.

  • He went on to become Queen Victoria’s personal surgeon, and won a bushel of prestigious honors,

  • including a lordship, for his many contributions.

  • And maybe most prestigious of all...Listerine Mouthwash? That was named after him.

  • That Pasteur-Lister one-two punch has probably saved billions of lives over the last 150 years.

  • Which brings us to our next science hero, who took preventative life-saving to a whole

  • new level with an arsenal of modern vaccines, starting with the shots you probably got as a baby.

  • Maurice Hilleman was born the youngest of eight children on a Montana farm in 1919.

  • His life got off to a rough start when his mother and twin sister died during his birth,

  • and he was raised on his uncle’s farm, tending chickens and reading Charles Darwin.

  • Then he went on to do some scientific research of his own.

  • By his mid-twenties, Hilleman had already helped develop his first human vaccine, one

  • designed to help protect overseas soldiers from encephalitis.

  • Weve talked about how vaccines work before -- but in a nutshell, they trigger your immune

  • system to make antibodies against a particular disease, without actively making you ill with

  • that disease.

  • This creates a kind of memory for your immune system, so if you run into that disease in

  • the airport or lunchroom or whatever, your immune system will be like, hey, I know you

  • and start cranking out antibodies to fight it.

  • Generally, to make a vaccine, you first have to mass produce the virus or bacteria, by

  • infecting cells grown in cultures, or sometimes chicken eggs.

  • Then, once youve got a good working supply, you can work on weakening that pathogen to

  • turn it into a vaccine.

  • Basically you want to administer just enough virus or bacteria to get the antibodies flowing,

  • without getting anyone too sick.

  • Hilleman was like, the Superman of this process.

  • Through his research on the influenza virus, he found that people did often develop an

  • acquired immunity the the virus’s small -- but constantly evolving -- mutations.

  • They did that on their own, without a vaccine.

  • But every now and again, the virus made a major genetic leap -- one big enough to leave

  • people with no resistance, and putting the population at risk for a wide-scale pandemic.

  • For example, in 1957, Hilleman heard about a really bad influenza outbreak in Hong Kong,

  • and suspected a new strain was spreading.

  • Once he and his colleagues got their hands on a sample of the virus, they found that

  • most people did, in fact, lack the necessary antibodies to protect themselves from it.

  • So, fearing the worst, Hilleman got a bunch of manufacturers to immediately start cranking

  • out a vaccine.

  • Over the next two years, about two million people died worldwide from that Asian flu.

  • But the total would have been far higher without Hilleman’s foresight and emergency vaccine.

  • Around that time, Hilleman joined the Merck pharmaceutical company and started developing

  • new vaccines against common childhood diseases.

  • For example, an American virologist named John Enders had come up with a measles vaccine,

  • but it proved too toxic to use.

  • Hilleman developed an improved version by growing a weaker strain in chicken embryos

  • -- and that vaccination alone is estimated to save over a million lives every year.

  • Then, Hilleman developed a mumps vaccination by isolating the virus from a swab from his

  • own daughter’s throat, and following the same protocol he’d used on measles.

  • Later he combined the two with a third one for German measles, or rubella, creating the

  • still popular MMR vaccine you probably, hopefully got as a toddler.

  • His team went on to develop many more vaccines, including those for Hepatitis A and B, chickenpox,

  • meningitis, pneumonia, and others.

  • They also contributed to a bunch of other major scientific breakthroughs, including

  • isolating a new family of viruses -- the adenovirus, a common cause of upper respiratory infections

  • in children and adults.

  • And, like the work of Lister and Pasteur, his research has since influenced generations

  • of researchers, paving the way for more medical breakthroughs and saving more lives.

  • Thanks for watching this episode of SciShow, which was brought to you by our patrons on

  • Patreon. If you want to help support this show, just go to patreon.com/scishow. And

  • don’t forget to go to youtube.com/scishow and subscribe!

Have you ever saved someone’s life?

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おそらくあなたの人生を救った3人 (3 People Who Probably Saved Your Life)

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    Yu Sheng Chen   に公開 2021 年 01 月 14 日
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