To swill or to smell: How John Snow determined the cause of cholera

26:13So the idea of contagious stuff was something that we could handle. Also, van Leeuwenhoek, whose name I will never say correctly. Let's have some Dutch listeners send in a correct pronunciation for comparison. Okay, great. And we'll send them to our audio engineer. And every time I have to say it in the future, he can just pick one of those and cover up my… That sounds great. My voice in the future. Okay. So in 1673, so like 200 years earlier, he had looked under the microscope and noted that there's a tiny microscopic world that, you know, none of us had seen before. But this connection between that tiny microscopic world could make us sick and kill us had not been made by a lot of people.

27:02There were some people out there who were maybe starting to think about it, but this idea that stinky air could make people sick was just really hard to shake and was much, much, much, much, much more popular. That's really fascinating. Do you think that revealing that microscopic world also connected with like existing ideas about reductionism, you know, that like our world at this scale is controlled by the behavior at a smaller scale? It's sort of in the same century as like atomic theory, which, you know, leads to reductionism in particle physics. But do you think that sort of thinking was widespread that we're like looking at the internal mechanisms of the world by seeing the microscopic view?

27:41No, I don't think that that had really taken hold with the biology folks yet, unfortunately. Like, you know, because the miasma theory was still so big. And it wouldn't be until like I think 1890 is when Cook's postulates came out and Lister's antiseptic technique doesn't come out until like something like a decade after Jon Snow does this experiments we're about to talk about. Like I think it took a while for those connections to be made. It seems so obvious to us now, but I think that's an example of how much modern philosophical assumptions we're carrying with us all the time. And so when we look back at what people were doing 200 years ago, like the connections and the conclusions seem obvious to us in hindsight.

28:22But at the time, like that's a big ingredient in understanding how the world works. So anyway, it's fascinating. So that means that in early days of cholera, we didn't really understand the germ-based mechanism for how this disease spread. I do think it's tempting to paint broad strokes, though, for an era and, you know, assume that everybody sort of had the same ideas. And there were some people in the era who were sort of thinking along the lines that Jon Snow would be thinking. So, for example, I'm going to jump ahead a little bit. In the same year Jon Snow does his experiments, there's an Italian guy named Filippo Pacini.

28:59My apologies to every Italian out there because I probably – That sounded correct. Oh, yeah. Nice. Okay. All right. At the University of Florence in 1854, he publishes a paper, Microscopal – and that's where I blow it. Oh, no. I'm not going to go back. I'm moving forward. Observations and Pathological Deductions on Cholera. He actually identifies the cholera bacteria and publishes on it. But the rest of the community was not ready to move past the miasma theory. And so for 30 years, his paper is essentially just totally ignored. So, like, there were other people out there. Like, this idea was in the air that, like, germs could be causing diseases.

29:40but like as a whole, the community was just not really ready to embrace this idea. But, you know, Jon Snow's paper is part of what helps turn the tide. Yeah, that's a really important point that there's a huge diversity of thinking and ideas, right? And sometimes you can go back and trace the origins of a modern idea on the fringes of academia or, you know, mainstream thought 200 years ago. Really cool. Yeah. All right, so tell us about Jon Doe and what he was doing. Jon Snow. Sorry, tell us about Jon Snow. That's what he was doing when he wasn't killing the White Walkers. Whatever that means.

30:16All right. So Jon Snow was, at the time of the outbreak we're going to be talking about, Jon Snow was a 42-year-old physician. He was a vegetarian and a teetotaler. So like some would say maybe not a ton of fun, but he seems like a cool guy to me. He had made his name by doing a bunch of experiments on ether and chloroform. So we did that episode on anesthesia and how anesthesia sort of came along in the 1830s, 1840s. So when it came out, there was this massive problem with like sometimes it worked, sometimes it didn't. And Jon Snow realized that that probably had a lot to do with like temperature and how it was being delivered.

30:55So he did a bunch of very careful experiments and created these like charts where like when the temperature is this, you should give them this much. And he created a device to try to standardize how much ether and chloroform people got so that they could always be anesthetized the right amount. And he actually became so famous for being great at anesthetizing people that he was able to give chloroform to the queen when she was giving birth to one of her kids. And so he became sort of famous for this. And despite being a teetotaler, he did a bunch of experiments on himself with chloroform and ether.

31:29So he wasn't drinking alcohol, but he was playing around with the chloroform quite a bit. And we think that this actually might have led to his somewhat early demise, unfortunately. But this is how he made a name for himself. Well, I've watched this show, Victoria, which is about the life and times of Queen Victoria. And Jon Snow makes an appearance in that series quite prominently about the cholera outbreak. But they also portray him in a very interesting manner. He's like awkward. I think he has a stutter. He's really not a very charismatic personality as portrayed by the BBC. I don't know if that's accurate.

32:06I don't get the sense that he's a super charismatic person, to be honest. But, you know, not all of us are super charismatic. Doesn't mean we're not making good contributions, Daniel. I'm just saying you sort of described him in a way that might make people think he was like, you know, swashbuckling or extravagant in some way. But no, I think he really was a data nerd, wasn't he? He was a massive nerd, yeah. Which is awesome. I mean that in the best possible way, right? It's my highest compliment. Yep. No, totally. Yeah, no, I don't think he was cool. I think this guy was a straight up nerd. But he's a straight up nerd that changed the world.

32:43So all hail the nerds. Yes, nerds can change the world. Thank you to all the nerds out there. Amen. All right. So he makes this observation in 1848. So cholera had spread through Europe, but then for a couple years it had sort of like disappeared from Europe. And then all of a sudden it shows up in Hamburg. And then this boat leaves Hamburg and shows up in London. And then suddenly cholera shows up in this hotel in one room that has a sailor that was on that ship from Hamburg. I got to ask, is Hamburg the German pronunciation or the Kelly pronunciation? because most Americans say Hamburg. I don't know.

33:25I can't be like Hamburg like hamburger, could it? Is it? That just seems too American. I don't know. I mean, that's what Americans usually say when they're talking to each other, but I wasn't sure if you were being all, you know, like correct German pronunciation. I think I'm overcompensating because I was in the Middle East recently and I kept saying Iran and everyone would be like, Iran, Americans. And I was like, oh, I guess you guys don't say Iran over here. But so you think it's Hamburg? I mean, I think Americans say Hamburg. I don't know what Germans say to each other. All right. Well, that German city.

33:59Okay. There was a German city that cholera popped up in. And a boat left with sailors from that German city. Yeah. Showed up in London. One of those sailors had rented a room, got cholera, died in that room. Before he could invent the hamburger. That's right. I know. What a tragedy. Thank goodness somebody else did because what would Americans be without their hamburgers? And then sometime later, somebody else ends up in that room and they get cholera and they die. And that's despite the fact that there hadn't been cholera in London for a really long time. Right. OK. And so Jon Snow thinks to himself, this is not good for the miasma theory.

34:39Right. Because why would cholera jump from that German city that I'm not going to say again ever and then all of a sudden end up in London in this one room where the German sailor was like he didn't bring the bad air with him. Right. Doesn't it seem much more likely that that there was some other way that the German brought the disease with him to London and then left it behind and gave it to somebody else? And he's like, I don't I don't necessarily know how he gave it to somebody else. And there was a doctor that visited both men and he didn't get it. And so that's a little concerning. I'm not really sure what happened there.

35:21But but also the doctor should have gotten it if it was bad air that happened to be in that hotel room. And so he's like, all right, I feel like the miasma theory isn't really explaining things. We need something else. So the thing I don't understand about the miasma theory is if it's just in the air and it's not like moving around, it's connected to the place. How in that theory does cholera ever spread from India or whatever to Europe? Right. Like doesn't that theory fundamentally conflict with their observations? Oh, man. OK, this could be a really long answer. I'll try to keep it short. So, all right.

35:55So it depends on the time and the place. So like way back, like when Hippocrates or like, you know, the many people who go by the name Hippocrates were like writing about disease. They would say something to the effect of like, if you want to understand disease, you need to understand which way the winds are blowing and how that changes seasonally because the winds were blowing diseases in from different places. And so understanding how the winds were blowing would impact what diseases people would get depending on what season. And so this idea sort of morphed over time and depending on where you were and when, the exact specifics would change.

36:30But I found a report from 1850, which was written by the health professionals living in London reporting on the epidemics in 1848 and 1849. So this is when Jon Snow was like starting to collect his data. And 1854 is when he really like collected the data, you know, the Broad Street pump data. And so this is like the time and place that's sort of relevant to your question. And they were saying that what mattered was that like the winds blowing out of India were like hot and moist. And so that's what was blowing the cholera and that it happened to be a time when, you know, first the winds that were blowing into Russia were hot and moist and then they were blowing into these other regions.

37:11So essentially they were saying hot, moist air was taking cholera on this journey. But, and this is kind of amazing, after doing this like long explanation of how the winds had brought cholera, you know, around the world, then they say, but also, you know, Scotland had cholera in January and it was really cold. Moving on. Outlier. And then they don't deal with it. And then they say, they start talking about how like it's complicated, right? So first you have to have the wind blowing cholera in, but then it needs to meet a population that has been impacted by something. And so like foul air could be the thing.

37:49So they talk about, for example, if people live in an area where there's lots of people for a few square feet. So, for example, if you have like 20 people in a small room, they're going to start breathing out bad air, like decaying matter, as they put it. and that is going to start to poison the air and the poison air that you're breathing in is going to make you more susceptible when cholera comes through. And it was really interesting. There's like this motivated reasoning that they find. So for example, there was a girl's school where the girls got sick and a boy's school where the boys didn't.

38:24And they claimed that that's because the boys kept breaking the windows in their school and they were getting better ventilation than the girls. And that's why they didn't get it because they weren't breathing in as much poison vapors as the girls were. So this is fascinating because I'm trying to understand the difference essentially in the two theories. Jon Snow is thinking it's basically transmitted from person to person by something created by the person and then transmitted through the water. And the contrasting theory is it's not really person to person. It's just like comes through the air.

38:55But now there's this other part of it where people can make it more likely that you get it from the air if you're also breathing out poison vapors. So in the miasma theory, it's not that they're breathing out cholera and passing it to each other in their breath. It's that they are making it more likely that the other girls are going to get it by being cooped up with their poisonous vapors. Right. That's so complicated. It's very complicated. I mean, you could also get those poisonous vapors by living above a cesspit or by living too close to a graveyard at a time when the graveyard is stinky. Like the graveyard has to be stinky.

39:32It can't be like a graveyard from 300 years ago where everybody has like long since skeletonized. It needs to be a stinky graveyard. Or a graveyard that smells wonderful. Yeah, right. Or a graveyard with lots of flowers or something. But, you know, it's interesting because then they'll say like, but, you know, there was this other recent cholera pandemic where it seemed to only hit healthy middle class people who weren't living in bad conditions. Moving on. Yeah. I guess this is like the epicycles of cholera, right? It's like you have this idea, you want to make it fit to the data, you keep adding bits and pieces to it and whirly gigs until eventually you just look, this isn't working and we have to tear it down and start from something else.

40:13Yeah, but so this report was written by Edwin Chadwick, who was like the guy in charge of like public health decisions in London at the time. And he for a long time, even after Jon Snow like came out with his big theory, would continue to push the miasma theory. There was even a section where the report noted that there were people who were sharing the same air and they differed in the water that they were drinking. And one group was drinking water that, you know, appeared to have given them cholera because that group got cholera. And another group drinking a different drinking water from a different source didn't get cholera.

40:45And it was as though he was trying to support Jon Snow's theory. And then he just moved on without, like, you know, digging into it anymore. And so there's all of these inconsistencies in the report. But at the end of the day, the guy who writes the report continues to be a miasma person making massive and important public health decisions in support of trying to get stinks out of the area, even if those decisions result in more sewage in the Thames, which is what is actually contributing to cholera. And so anyway, the miasma theory is sort of inconsistent, has to do with the wind and the stinks and maybe some other stuff that we can't explain.

41:24And so, yeah, the answer is it's not a very like internally consistent theory. Hmm. Yeah. And it's tempting to judge these folks and be like, how could you believe this when the data was saying the opposite? But it's so easy to do that in hindsight when we know the truth and it's clear. And, you know, they're at the forefront of human knowledge. They don't understand. They're doing their best to make sense of the data. Nobody's perfect. So it's easy to criticize. But who knows what we would say in their shoes. I mean, absolutely. And this was an era, you know, before the germ theory really was established.

41:53And, you know, you get a school where the windows were broken and the kids were fine and another where they weren't. Like, I can totally get thinking like, OK, maybe ventilation did matter. And I don't know. I don't judge them too harshly. But it is a bummer that they didn't listen to Jon Snow because people died. So then basically Jon Snow's big idea is that somehow the disease is moving with the person, right, that it's coming with him. He's carrying something with him and it can then go from person to person. And his hypothesis is maybe it's water-based. Yes. Cool. And he had also had a little bit of prior experience with cholera because he – in the prior pandemic, he had been training as a physician and he had worked with some coal miners.

42:34and they weren't experiencing the right kind of bad air that was popular as an idea for transmitting cholera at the time. And they happened to be working in an area where their food and their water was mixing with human waste while they were down in the coal mines. And that was getting his mind on this idea of like contamination as a way of transmitting cholera. And so at this point, he starts to get water on the brain. And so to follow up on this idea, he collects two sets of data in 1849 to start getting this waterborne idea rolling. I think this is a really important moment here, actually, because he doesn't have enough evidence to conclude that it's water-based or it's contaminated.

43:14He's just kind of got a hunch, right? And it turns out he's right and he does the experiments, which prove it. But your hunch doesn't have to be – but your hunch doesn't always have to be, like, based in evidence, right? Science is about taking these leaps and asking questions and then backing it up with data. But they're important moments of just kind of guesswork. Yeah. And this first moment was just him thinking, well, wait a minute. The prominent idea of the time right now just doesn't make sense with this observation. So what else might make sense? Very cool. And so these first two mini experiments that he does, we're not even talking about the big Broad Street pump experiment yet.

43:50These are just like little places where he dips his toe in to be like, could something else make sense? And so the first thing he did was he went to essentially like a slum in London in 1849. And he finds this row of cottages that are all connected and they all share a well. And there's like a crack and that allows essentially sewage to seep into the well when it gets too rainy. And everybody in those cottages had died of cholera. And then right nearby, he finds like the exact same setup of cottages, but their well is more sound. And when rain comes, they don't get sewage in their well. And only one person in that row of cottages got cholera.

44:33And so he's like, well, it looks like you get sewage in the well and then you drink from the well, you get cholera. And so he's – Solid theory. Poopy water kills you. Poopy water death. And so he's so he collects those data. And then the next set of data that he collects looks at the Thames. So the Thames is the big river that flows through London. Correctly pronounced by Kelly, by the way. I've been to London. Ding, ding, ding. Ding, ding, ding. I'm sure if I hadn't, I would have said Thames or something.

45:04If you had, we would make you famous for it. Oh, thanks. Yeah, no, I definitely saw it on a map and then heard someone say it and had a like. Like, I had a moment where I was like, I'm going to be quiet until I convince myself that these are the same things. And anyway, OK, so so based on where the sewage was being emptied into the Thames and the Thames ended up being the source of the great stink years later because so much sewage was emptied into it that it like killed the fisheries and stuff like that. So anyway, based on where the sewage was being emptied into the Thames, Jon Snow hypothesized that casualties from cholera should be much higher in the south part of the Thames for people that are getting the water from the south part of the Thames than if you're getting it from the north.

45:48And what he found was that if you are getting your water from the south part of the Thames, eight out of a thousand people are dying there. And if you get it from the north or the west, one out of a thousand people are dying. The idea being that the north has less poop in it because it's like upstream. Yep, exactly. But if you live on the east end of London, the east end is an area that was like super destitute and super stinky, right? So if you believe in the miasma theory, that's where most people should be dying. But they like should maybe have an intermediate amount of sewage in their water.

46:22And they only had four out of a thousand people dying from cholera. And so he's arguing that like this is actually pretty good data suggesting that this is the cholera is coming from the water and not coming from the air. Because the death rate follows the river. The more downstream you are, the more likely you are to die. Exactly right. So it follows the like the sewage gradient. So he publishes these results. The reviews are pretty positive, but they're also pretty skeptical. And so there are people who are saying like, look, you found a correlation, but you haven't actually found a cause. Good point.

46:57Solid critique. That's true. And the London Medical Gazette in particular says, you know what we'd really love to see? We would love to see you find a case where somebody takes water that's contaminated and goes way far away and then drinks it and then gets sick. Like way far away from what could have been the source of contaminated air and then gets sick and dies. And we'd also like to see some people who are in an area where there could be bad air, but they didn't drink the water. and they don't die. That kind of stuff might convince us that it's not miasma that happens to be in the same area that's actually causing the problem.

47:35I agree these are all incisive experiments, but they feel so unethical to me because we're talking about people dying. Right, but he's not doing these experiments. They're like, if you could get observational data that meet these criteria. And so Jon Snow is like, oh my gosh, where am I gonna get these observational data, right? This is gonna be really hard. And so, and this is amazing, this is like two geeks in the night meeting together and magic happening. So he goes to the London Registrar General. This is like the guy who keeps track of the birth and death stats. And this guy is a stats nerd.

48:07Another nerd, awesome. Another nerd. And his job was just to keep track of like when people are born and when people die. But he was like, you know what? These data could be so much more useful if I knew more stuff. And so he started encouraging doctors to not just tell him when someone died, but why they died, how old they are, what was their occupation, Where did they live? And after talking to Jon Snow, he starts also collecting information on where they were getting their water, which was amazingly useful because Londoners were getting their water from like a handful of different companies that had pipes that were like crisscrossing their way under London.

48:44And so, you know, you could live in a house and get your water from one company and next door could get their water from a totally different company. And these companies had very different standards for how they treated their water, where the water came from. But there were two main companies that were servicing an area that was kind of near where Snow lived. One of the companies had upgraded where they were sucking the water from so that it was less likely to be sucking in sewage. And the other one hadn't done that yet. And these companies also differed in how saline the water was. And so you could tell the difference between the water by doing a water test, and one of them was a little saltier than the other.

49:23And so it was possible to know who was getting what kind of water, either by asking, who do you pay your water bill to, or by taking a water sample and checking to see how much salt was in it. And with this setup, Jon Snow, five years later, when a massive outbreak came a couple blocks away from his home, he was prepared to collect the data that would show that cholera was a waterborne disease. And when we come back from break, we'll hear all about how nerds saved the world. Nerds!

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53:01All right, we're back and we're hearing the story of cholera, how it kills you, how it spreads and how nerds figured it all out. So is Jon Snow at this moment when he has his idea and he's waiting for his data, is he still like a real outlier in the community? Nobody's really taking it seriously because it feels like if this is a possibility, even then somebody should like do something about it. work hard on reducing the poopy water that people are drinking because we're talking about lots of lives. Yeah, he's still kind of an outlier. The main people who are in charge of the public health are much more concerned about the stinkiness.

53:37So at the moment, the way waste is sort of managed in London is a lot of people have what are called cess pits underneath their houses. And so you poop in a bowl and then you dump it in a pit underneath your house. And when that pit fills up, you pay somebody to come scoop it out and haul it away, which is part of why everything stinks a lot. And so to try to get rid of that stink, people are starting to create a sewage system that pipes it all into the Thames. And that if you believe that stink causes cholera, dumping the waste into the Thames sounds like a good idea. But if waterborne contamination causes cholera, you are killing people by pumping waste into the Thames.

54:23And so at the moment, they are changing the system and essentially dumping the waste into the Thames instead of using the cesspit system. So yes, snow is pushing against the tide at the moment. Fascinating. All right. All right. So it turns out that this giant outbreak happens at Broad Street Pump. So Broad Street Pump is this very popular source of water. It's well known because it's a very hot summer in 1854. And this pump produces cool water that is supposed to taste way better than the nearby pump. People really like it. So a lot of people come to this pump. An outbreak starts at this pump.

54:59And Jon Snow runs to his friend, the statistician. And he says, all right, you've got data on the people who are dying. Can I have that data? and his friend shares the data. And Jon Snow looks at the data and he says, all right, these people are like, they're near the Broad Street pump. And he starts knocking on their doors. He's like, where are you getting your water? Where are you getting your water? Where are you getting your water? And he realizes that the Broad Street pump seems to be the source of the death, the source of the cholera. And so he starts like following up on all of the deaths whenever he can, but sometimes he's too late and everyone in the family has passed away and he can't get the data that he needs.

55:35But by following up, he starts to find some sort of interesting situations that are interesting and that they help fulfill the criteria that folks had set forth for him previously, which is to say, we want you to give us examples where water was taken from the pump far away from the area where there might be stinky air and then consumed and then kill people. And so there were these brothers called the Eli brothers. They had a factory in town. The factory made percussion caps. These are caps that make it so that when you shoot a gun, if you shoot it even in the rain, it's going to go off anyway.

56:08So it essentially like protects the gun under wet conditions, which is important because the Crimean War was happening. They had brought Broad Street water pump to give to their factory workers. Because again, this is supposed to be like the best water around. And a bunch of their factory workers started dying. They also brought it to their mother who lived in a town farther out. And the mother then shared it with their niece and both their mother and their niece died. Oh my gosh. They're basically poisoning everybody they know. All these people that they love and care for. Right. And so that ended up being pretty good data for them, unfortunately.

56:43And why, again, is this water so famous and popular that they're carrying it across town to share with people? So the water, the other water in a nearby pump came from a different source, and it was notoriously kind of like stinky and gross and maybe a little bit warmer. But this Broad Street water must have had poop in it, right? That's why it's killing people. But it's also famously delicious. This is the thing I'm struggling to reconcile. Yeah, well, so, you know, probably at this time, Daniel, everything was gross. And this was just had a good reputation for being less gross. I see. And also, I think it came from a little bit deeper.

57:16So it was cooler during a particularly hot summer. And also, if it was the one that's like right in front of your house, you probably just, you know, go for it. No offense to all of our listeners in London. I was just curious, what flavor of poopy water Londoners preserve? Well, I hope that things have gotten better, you know. All right. Right. So he figures out that there's a cluster connected to this one pump. And then he finds this example of people carrying that water from that pump to places far away and those people also dying. Yes. And then he finds some exceptions to the rule. So he finds a workhouse that is very close to the pump.

57:50And so he would have expected a bunch of the people working at the workhouse to be dying of cholera. But pretty much no one is dying of cholera there. So he goes to the workhouse and he's like, what's going on here? And they're like, oh, actually, we have our own private supply of water and we have our own well. So we don't go to Broad Street Pump. They're in the same area breathing in the same bad air, but they're drinking different water. So they're fine. So the caller is following the water and not the air. Exactly. Yes. And then something similar is happening at a local brewery. Turns out the Broad Street Brewery guys are mostly just drinking malt liquor and not drinking Broad Street Pump water.

58:25So they're OK. So he's got this list of 83 people who had died. 73 of them are really close to the pump. And so he's thinking like, okay, probably these are people who drank from the pump because it's the closest pump. Why wouldn't they have drank from it? 61 of them, he's able to confirm that they definitely drink from Broad Street pump. So they almost certainly died from that. Six of them say they're definitely not Broad Street pump drinkers. So maybe they, you know, got it from somewhere else. Six were mysteries. He just couldn't track down any living members or anything like that. And then he had 10 cases that were far enough away from the Broad Street pump that he's like, well, you maybe went to a different – there was probably another pump that was a little bit closer.

59:08But he still ended up thinking that those people had probably drank from the Broad Street pump because, for example, it looked like they frequented a coffee house that used the Broad Street pump water to make a special thing that they called sherbet, where they had mixed Broad Street pump water with some other stuff. And then their customers had started dying. You say a special thing like sherbet as if nobody's heard of sherbet? They called it sherbet. It wasn't like sherbet like we would call it today. They were mixing like a effervescent. I don't remember exactly what it was. Maybe I even shouldn't have used the word sherbet.

59:41They called it sherbet, but it wasn't – the description wasn't any sherbet that I recognized. I see. All right. So he's essentially pulled together this list of people who have definitely died of cholera. A very high percent of them had drank from the pump. He's got an extra list of people who have like drank cholera far away from the area where it could have been explained by just bad air. and they also died from the water. You've got people who are close by the pump, were breathing in the air, but they didn't die. So he's pulling all these data together. But there's still some people who are missing that he can't really figure out.

1:00:16Like they left town. He wants to know if they died or not. And he's really trying to track down like the first case that started everything. But he just doesn't have the like knowledge of the town that he needs to do this. But he starts talking to this reverend, Reverend Whitehead. and this reverend knows this community intimately. This is his flock. He's been actually like in the houses with a bunch of these people as they've been passing away. He's been, you know, holding their hands. He knows everybody here really well. So he's able to track down a bunch of the cases that are missing and confusing because he knows everybody.

1:00:50He's like, oh, you know, yes, that person left and they went to, you know, this town and I know their grandma, so I'll try to figure out where they went. And by going through old records, he's able to figure out the first case that brought cholera in to town. And it turned out there was a baby that got cholera and the mom was washing the diapers out and she dumped the pails of dirty water into the cesspit in the bottom of their house. And then they had the cesspit examined and it turned out there was a crack and the water was seeping into the well that served Broad Street Pump. And so usually Broad Street Pump did have pristine water, But this one cesspit was leaking.

1:01:32And when cholera got dumped into it, for a very short period of time, cholera was introduced into the pump. But it was just this one case. And so actually the cases of cholera were starting to go down when Jon Snow went and talked to like the public health board and was like, you guys have to remove the handle to Broad Street pump because this is what's giving everybody cholera. And they listened and they took the handle off. And so usually this story goes, Jon Snow saved everybody by removing the Broad Street pump. At this point, the pandemic was already wrapping itself up because the baby had died and there wasn't more cholera being introduced.

1:02:07But the dad ends up getting cholera, and presumably his waste would have also been put into the cesspit, and that might have started up another round of cholera. So he could have saved the town from another round of cholera. But the rest of the people in the house – and this is disgusting – instead of throwing their waste into the cesspit, they were throwing it into the backyard because they didn't want to – like they didn't have access to the downstairs cesspit. London was super gross. so anyway with this information and the extra information that the reverend gave him by having this like amazing social network that he was able to use to like fill in the gaps that Jon Snow wasn't able to fill in on his own Jon Snow was able to publish this data and make a really good case that it's not foul air it's waterborne contamination and so what do you think Daniel do you think after that everybody was like, we will never speak of the miasma theory again.

1:03:06I think it takes a long time for a new idea to become mainstream, doesn't it? Yeah, it does. Yep. So it wasn't immediate. There was still pushback. There was, you know, even in the city of London, there were people like health officials who were like, it's miasma. You didn't really show anything at all. But by like 1866, which is about a decade later, The Lancet is final, which is a huge Medical Journal was finally saying something like, all right, yeah, Jon Snow, he was probably onto something with that theory. And it's getting broader acceptance. And in 1867, Lister is coming up with his antiseptic technique.

1:03:44So this is where you like, you know, if you're going to do an amputation, you should probably clean it off to make sure there's no bacteria in there before you close up the wounds so you don't kill people with infections. And then in 1876, Robert Koch does this amazing work showing that anthrax is caused by a bacteria, and then we're really off to the races with the germ theory of disease. Yeah, that's really fascinating to see how long it takes a new idea to be accepted. And, you know, some people hear this and then they say, well, academia is too slow and it takes forever. And that's probably true.

1:04:15But it doesn't mean that every idea that hasn't been adopted is valid and should be taken seriously, right? The lesson is to follow the data, right? The data should speak. The data will tell you the truth about the universe. And it's Sometimes it takes academics a while to come around to the data because they have other theories in their minds. But every new idea needs data to support it. And the other thing here is, you know, like, Jon Snow was able to get moderately convincing data in 1849 during one pandemic. And then he had to wait another five years for, like, the, you know, the right set of conditions to come about.

1:04:49And unfortunately, the right set of conditions was a lot of – was people dying. That baby killing all those people. Yeah. Babies. Shake my fist at babies. The other fascinating thing there is that the pandemics end on their own. Is that a feature of the thing we were talking about earlier, that cholera kills you so quickly that it's not optimized for spreading continuously? I don't think it's always self-limiting. So in this case, it was self-limiting because there was only one family that had access to the cesspit that could leak into the well that fed Broad Street Pump. I think if the entire community had their waste emptying into the Broad Street pump, maybe you would have figured it out faster because then it would have been really obvious that there was poop in the pump.

1:05:32But, I mean, in general, I think I read that when one person gets sick with cholera, they can produce a trillion cholera bacteria that can then get into the water. And so, you know, I think as long as cholera is getting into the water and people continue to drink that water and you've got more people who are, you know, contributing more bacteria, I think it can keep going for a while. All right. Well, tune in next week for more details on cholera. If you haven't had enough, 20 liters of cholera details is not satisfying you. We're going to learn more about how cholera works, how we can treat it, and the biological and chemical mechanisms underlying all that diarrhea.

1:06:12Yay, nerds. See you next time.

1:06:21Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We would love to hear from you. We really would. We want to know what questions you have about this extraordinary universe. We want to know your thoughts on recent shows, suggestions for future shows. If you contact us, we will get back to you. We really mean it. We answer every message. Email us at questions at danielandkelly.org. Or you can find us on social media. We have accounts on X, Instagram, Blue Sky, and on all of those platforms, you can find us at D &K Universe. Don't be shy. Write to us. When Kohler, global design leader in luxurious kitchen and bath products, asked me to be their ambassador for timeless, elegant, durable cast iron, I said, I'm in.

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