They deliver babies. They help you when you’re sick. They’re the ones who examine…all the things.

Doctors keep our health in check. And they spend years of training to do it.

But that wasn’t always the case.

Medicine for most of the 19th century was completely different to how it is now. In America, there was virtually no regulation at all. Anybody could declare himself or herself to be a physician.

Most physicians graduated, never having practiced at the bedside, never having performed surgery, and they probably never even seen a laboratory.

This was not a lucrative profession. It didn't tend to attract people coming for money and very, very few people were willing to invest a lot of money in an education

So basically, it was a job no one really wanted to do. On top of that, medical science itself was still unsophisticated.

Many surgeons weren’t totally sure what even caused infections; so to treat some of them, they’d often just cut off a person’s limbs. No big deal.

They were also pretty “meh” about keeping their practice sterile.

if you were a surgeon in the 1860s, the 1870s, you might, well, try and keep your wards clean and the surgical table clean-ish…

Yep. “-ish”.

…but you're very likely to be operating in a leather apron which is stained and encrusted with blood and other bodily fluids which have accumulated over perhaps decades. In fact, many surgeons would wear their bloody leather apron as a badge of honor because it revealed to everybody just how many operations you'd performed.

It would take years before they learned how unsanitary this was and before they decided, “Hey, maybe we shouldn’t do that.”

Up until then, doctors and scientists slowly began to prove that illnesses and infections were caused by microscopic organisms. This idea, called the germ theory, was a big deal at the time – but a lot of people didn’t buy it.

People would say there's absolutely no way that a tiny microscopic organism could possibly kill an organism as big as we are.

Cue Ignaz Semmelweis.

Semmelweis was a Hungarian who was working in a maternity ward in Austria. In the 1840s he noticed, that women who gave birth in one particular ward. They were dying much more commonly than the mothers who were giving birth in a nearby ward.

There was a big difference between these two wards. In the first one, doctors and medical students would spend part of the day in the morgue and the rest of the day in deliveries. They were passing these germs from the corpses to the birthing women and leaving extraordinarily tragically high numbers of babies without a mother. The other ward was run by nurses who did not participate in autopsies, and that's why those mothers were far, far less often dying.

Semmelweis argues that some kind of living matter is killing these women and the doctors were transferring it from the dead to the living. Semmelweis installed a bowl of disinfectant in the ward and insisted that all of the carers wash their hands in it. The rates of death plummeted.

The sad thing is, people still didn’t get on board with Semmelweis’s argument about this “living matter”. But why?

There were a lot of reasons, but one of them is that it was absolutely intolerable for a large number of physicians and obstetricians to recognize that they had unwittingly caused the deaths of hundreds or even thousands of women. Many of them just simply couldn't accept this.]

But by the 1880s, after more and more scientific proof, a lot of surgeons started accepting the fact that germs caused illness. They even began to make some changes.

So they're starting to wash their hands.

They're also starting to use tools which don't have any spaces where bacteria could gather. You think of a classic scalpel, you'd have a wooden handle, and then you'd have the metal blade. Any number of places in which bacteria could secrete themselves and then cause infection.

By the early 1900s they're starting also to wear latex gloves and that's a huge improvement as well. So surgery becomes safer.

It was in less than a generation that surgery was becoming revolutionized in this way.]

And once physicians and scientists know which germs are causing certain illnesses, they develop the first vaccines to target specific diseases – and then antibiotics to treat infections (and save a lotta limbs…).

And Semmelweis?

It wasn't until germ theory was fully established that people looked back and rediscovered Semmelweis.

In the early 20th century, the late 19th century, statues to him are erected, all sorts of biographies are written. He's hailed as a great hero.

Once surgeons could guarantee a clean environment in which to operate the entire field of surgery just blossoms. And it becomes the most prestigious field of medicine.

You also see huge changes in the way doctors were trained. By the early the 20^th century, over a hundred medical schools were founded in the U.S. and training became more intensive. Medical students began to truly learn the science behind medicine.

it was the first time in human history that medical scientists really knew what caused people to die of infectious disease. Now, the immediate offspring of this: more public health, better public health, better cleaner surgery and so on, is already starting to save lives. It's quite a remarkable thing to see.