By late July and August, after a few months of summer, heat seems baked into the sidewalks streets and brick buildings of New York City. When you step outside, you can feel the warmth rising from the pavement, and the stale air, trapped by all the tall structures packed on each street, engulfs you. It feels like you're living in the interior of an oven that someone has left on, that never is opened, never gets any fresh air. And on summer mornings, before the garbage is collected from all these homes, offices, restaurants, and bars, the smell from the street can hit you like a crashing warm wave of awfulness.
It can be pretty bad. But you know what? That smell can't kill you. We know that now. In Victorian England, though, doctors and scientists were convinced that it could, and this belief distracted them from finding and understanding the true source of the horrific cholera epidemics that swept through the city in the middle of the 19th century. In Ghost Map: The Story of London's Most Terrifying Epidemic—and How It Changed Science, Cities, and the Modern World, Steven Johnson tells the story of how a few determined men turned the tide of this conventional wisdom and helped bring about the changes that now allow large numbers of people to live together in these lovely, horrible, wonderful things we call cities.
By the 19th century, London had around two million residents, an unheard of number of people to be packed into a small space of a few miles. A lot of people produce a lot of waste, the result being that daily life was typically lived not far from huge piles of human excrement. When cesspools in basements or courtyards filled up, "night soilers" came and shoveled them out (yes, the job did pay well…btw, I should point this out now—this is not a great book to read while eating. In fact, it's the kind of book that may have you wondering after a few chapters whether your next choice in reading material should be about cake decorating or apple blossoms or the history of lace and how fast can you get through this to get to one of those much nicer topics. Fortunately, you do become immune to the subject matter after a while. It probably helps if you've ever had to deal with something like a sick dog or, I would imagine, a baby).
The first cholera outbreaks struck England in the 1830s. It's a disease that attacks with horrifying swiftness and efficiency, basically forcing all the water out of a person's body (vomit, diarrhea, you name it—hey, I warned you this was yucky stuff); towards the end, so much liquid is gone that a victim's skin became blue and leathery. The worst part, as Johnson explains, is that the sufferer is brutally aware of all that is going on; this isn't a disease where fever produces merciful delusions or a coma helps the mind escape the pain. Cholera victims were painfully conscious of their bodies' self-destruction. The only good part, if there is such a thing, is that the course of the illness was relatively quick; in many cases, death came in a matter of hours.
Doctors and scientists argued in the editorial pages of newspapers about the cause of the disease and how it could be cured. Advertisements for quack remedies were common (just like today!). The one thing most people could agree on was that the disease was caused one of two ways: either by human to human contact, or through "miasma," that is bad air.
The miasmists were convinced that the air of London was killing people. After all, it smelled terrifically awful. And of course, the bad smell was the result of so many people jammed together--not to mention the livestock that lived side by side with humans. Certain businesses added to the stench—slaughterhouses, tanners, soap makers were needed, but scorned as professions because of the poisons they released into the air.
At its most basic level, the idea that bad smells are things we should keep away from isn't wrong—part of human and animal survival is that our noses tell us to stay away from certain things, most notably rotten food or liquids. But those things make us sick because we ingest them, not because we smell them. Nevertheless, the Victorian scientists clung to this idea that "smell kills." After all, the worst diseases were typically clustered around the poorest neighborhoods, which were also the dirtiest and the most crowded. The air in those places was worse than that of the wealthy neighborhoods. And if some people in a house in a poor neighborhood were killed by something like cholera and others were spared, they had an explanation for that too: the survivors had a stronger internal constitution. Now obviously some people are stronger than others, but cholera didn't seem to strike down the weak and sick more than the strong and healthy. But there was an explanation for that, too—the survivors or those who were never struck were "braver" or more morally upright, and of course it was a given that the slovenly poor were less morally upright than the middle and upper classes.
Edwin Chadwick, the commissioner of health in London, was one of the leading proponents of the "smell kills" theory. He decided that the best way to deal with the problem was to get all the waste out cesspools, cellars, and yards. He had a sewer system jerry-rigged together that transported waste into the Thames. Everyone noticed that the water supply was now a lot dirtier, but astonishingly, given the choice between dirty air and dirty water, the infested water was seen as the lesser of the evils.
John Snow was a doctor who had made a name for himself with his pioneering work in the field of anesthesiology. In the 1840s, doctors began to experiment with the use of ether during operations. No one doubted that ether made surgeries remarkably more bearable than the previous painkilling methods ("Here, have some wine. And scream all you want."). However, it was wildly unpredictable—some people never went to sleep, some woke up in the middle of procedures, and of course, some never woke up at all. Snow was the first to recognize that the problem was a matter of dosage and conditions (the temperature of the room had an effect on the concentration of the gas). After painstaking experimentation, he not only created a table of dosages that worked consistently, but also invented an inhaler that controlled the amount of ether given to a patient. Snow became so well-regarded that he was called in to administer ether to Queen Victoria during the birth of her eighth child.
It was exactly this understanding of how gases worked that made Snow question the miasma theory, especially in the case of cholera outbreaks. He noticed several facts that clearly indicated that cholera was not spread via the bad-smelling air. One was that sewer workers, night soilers, and others who worked with noxious waste were able to do their job without being struck down; if the noxious air caused cholera, shouldn't night soilers be struck down within hours of doing their work in cesspools? Snow's understanding of gases also told him that a poisonous substance that was released into the air would diffuse so much that a cloud hovering over a neighborhood, as many scientists believed was the cause of the disease, would be too weak to cause illness--at least immediate illness. Breathing air filled with soot and particles for a period of time of course would have a negative effect, but that led Snow to another point—if bad air, taken in either in a short period or even over a longer period of time caused illness, then wouldn't it be an illness of the respiratory system? Cholera affected the digestive system. That led Snow to believe that the disease had to be caused by something that was ingested, not inhaled.
Snow had previously investigated a cholera outbreak in 1848-49 and had become convinced that the disease was caused by bacteria in water. When the 1854 epidemic struck in an area of London known as Golden Square, he began the painstaking process of speaking to residents of the area and trying to find out where they had gotten their water. Most of the victims were from an area that got its water from a pump on Broad Street, but there were outliers—people from a few blocks further who should have been using the Broad Street pump were also felled, and even more peculiar, a woman who lived outside the city became sickened and died from cholera right at the same time the Golden Square epidemic erupted. Further interviews revealed that the Broad Street pump actually had a reputation for having some of the best water in the area. People walked from a few blocks away just to get water from Broad Street. The woman who lived outside the city had loved the Broad Street water so much that her sons always brought her some when they went to visit. They had just given her a fresh supply around the time everyone else became sick.
Two other things stood out that added to Snow's theory and punched holes in that of the miasmists. A brewery near Broad Street employed a number of workers, but none of them became ill. They never drank the water; the workers at the brewery drank their beer. A workhouse right near Broad Street and the epicenter of the epidemic had about 500 residents but none of them suffered from cholera either. Snow found out that the workhouse had a private well and they never used the Broad Street pump. If a miasmic cloud was spreading cholera, shouldn't these large groups have been struck? And if susceptibility to illness was based on things like morality and internal constitution, shouldn't the workhouse—the home of the poor, the frail, the indigent, the alcoholics—have been decimated?
Prevailing wisdom is a difficult wall to break down. Snow's theories were dismissed by the medical establishment, despite what one would think was his own good standing amongst them. Even when the board of health sent a committee to investigate the area and do their own study, the questions they were armed with were meant to gather evidence to support the bad air theory—questions about air pressure, humidity, direction and speed of the wind, clouds, ozone. None of the questions were about what the sick and the dead had drunk or even ate. The examiners thought they knew the source of the problem and any ideas that did not fit their beliefs were dismissed or jammed and reshaped until they fit. Science can take enormous giant leaps, but it also can change at a glacial pace when a bedrock belief is challenged, no matter how logical, rational or self-evident that belief is. Snow had an extraordinarily open mind that allowed him to dismiss all that everyone was telling him was true, and the patience to analyze all the evidence available without prejudice until only the logical conclusion remained.
Snow didn't do everything on his own, of course. He was immensely aided by the work of William Farr, the city's demographer, who urged doctors and priests to collect more than just names and dates of death, but also ages, neighborhoods, occupations, and lastly, where the dead had gotten their water. He actually was not a complete believer in Snow's waterborne theory, but was intrigued enough that he began to collect the water information. Another key player was Henry Whitehead, a minister, who at first also was not sold on Snow's theory. His local parish board had listened do Snow and found his evidence persuasive, voting to remove the pump handle. Whitehead was outraged (as were many locals fond of the water). He knew the reputation of the Broad Street pump and how well-regarded its water was. But after setting off on his own investigation to prove that the pump was not at fault, he began to believe Snow and turned from adversary to aid. Whitehead had something Snow didn't—an intimate knowledge of the neighborhood and its residents. The young minister knew more about the daily habits of people in the area and was able to find and talk to the right people. He even was able to to track down his parishioners who had fled the neighborhood when the illness began to spread and gather additional evidence from them. Snow had become convinced that it wasn't that the Broad Street pump was perpetually contaminated but rather that the cholera outbreak was due to some specific incident. Whitehead was the one who found it—a young mother whose baby had become sick with cholera right before the beginning of the epidemic had thrown the baby's soiled diapers into the cesspool behind her building. At the urging of a committee led by Whitehead and sponsored by his parish, the cesspool was excavated. An earlier excavation of the pump had shown it to be in good condition, but the investigation of this specific cesspool showed that it was in such poor condition that its dirty water was contaminating the well water at the Broad Street pump. The mystery of the epidemic that had devastated a neighborhood in an astonishingly short period of time seemed to have been solved.
Everything made sense except to the miasma true believers. It took years before they began to believe, but eventually the tide began to turn. One important incident was a terrible smell that hit the city in the summer of 1858. William Farr, the city demographer noted that the number of deaths in the areas most affected by the nasty cloud didn't go up. If a smell that was so bad it was nicknamed "the Great Stink," a stench so awful that even seemingly jaded Londoners took notice didn't kill people, then how could any smell kill? Further, the Great Stink proved to be the push needed for the city to build a sewer system that would carry sewage far from London. The system designed by engineer Joseph Bazalgette, was completed in an astoundingly short time; most of it was up and running by 1865, truly one of the great wonders of the Industrial Age. Snow's theory about cholera, that it was caused by a bacteria carried in water contaminated by human waste, was proved resoundingly again in the aftermath of the sewer building project. Another epidemic broke out in 1866, killing more than four thousand people. The now converted William Farr tracked the center of the epidemic down to an area whose water was supplied by a company that had only partially installed the new filtration system. All the areas with the new sewers and filtering process escaped the outbreak.
Snow hadn't lived to see this. He had died of a stroke in 1858, during the Great Stink, of all times. He had left something else, though, that validated his work: a map showing the pattern of deaths during the cholera outbreak and their location in relation to water supplies. His "ghost map" was widely reproduced and studied and played an important part in convincing people. It is one thing to read a scientific report, but quite another to see it all lain out in a clear, easy to understand pattern.
Johnson does an admirable job of taking the clues and weaving it into a creditable narrative that includes the lives of Snow, Whitehead, Farr, and the residents of a neighborhood now lost to history (the Broad Street area is now quite chic). He also includes fascinating detail about city life at that time, Victorian medicine, and more than you ever thought you'd want to know about waste treatment throughout history. He clearly takes great delight in his subject, as well as his main theme of the book—that it took a seeming incredible convergence of the right man in the right place at the right time with the right disease to help the world make a tremendous leap forward in medical understanding—the dismissal of the miasma theory as a cause of illness—that in turn led to technological advances that made city living possible not just for the two million Londoners of the time but in the cities of today that operate at many times that size. The last section of the book, in which Johnson extols the wonders of urban living (cities are better for the environment! They're centers of ideas and creativity! The web and systems such as New York's 311 number provide information that would help scientists stop an epidemic more quickly! And did we mention that they're better for the environment?) and then points out the dire consequences of the megacity (a biological attack or nuclear bomb would kill more people quickly than in an urban area, wiping out governments, thinkers, and cultural leaders that would lead to an end of civilization as we know it, for a while at least) is less enthralling. It's nice to theorize and speculate etc. but it's definitely an anticlimax to the rest of the book.
But the point of Johnson's book is still an important one—that in times of crisis or when problems seem intractable, it takes someone who is willing to be a clear, critical thinker, who can step outside of that famously clichéd box to see through the, well, miasma of misinformation. The only way to find an answer or create change is to believe what we really see, not what we want to see, and to trust what we think is right, not what others tell us is right.
And now, after all that, I think I'm going to go buy some pretty flowers.