The Ghost Map: The Story of London's Most Terrifying Epidemic--and How It Changed Science, Cities, and the Modern World

by Steven Johnson

but the smell it emitted was not a public-health risk. No one died of stench in Victorian London. But tens of thousands died because the fear of stench blinded them to the true perils of the city, and drove them to implement a series of wrongheaded reforms that only made the crisis worse.

How could so many intelligent people be so grievously wrong for such an extended period of time? How could they ignore so much overwhelming evidence that contradicted their most basic theories? These questions, too, deserve their own discipline—the sociology of error.

“New ideas need old buildings,”

Most world-historic events—great military battles, political revolutions—are self-consciously historic to the participants living through them. They act knowing that their decisions will be chronicled and dissected for decades or centuries to come. But epidemics create a kind of history from below: they can be world-changing, but the participants are almost inevitably ordinary folk, following their established routines, not thinking for a second about how their actions will be recorded for posterity. And of course, if they do recognize that they are living through a historical crisis, it’s often too late—because, like it or not, the primary way that ordinary people create this distinct genre of history is by dying.

England itself was spared, which led the pundits of the day to trot out an entire military parade of racist clichés about the superiority of the British way of life.

But a family dying together, slowly, agonizingly, with full awareness of their fate—that is a supremely dark chapter in the book of death. That it continues on as a regular occurrence in certain parts of the world today should be a scandal to us all.

Snow’s work was constantly building bridges between different disciplines, some of which barely existed as functional sciences in his day, using data on one scale of investigation to make predictions about behavior on other scales.

It was a kind of haunting, couched in the language of pseudoscience: the dead of one era’s epidemic returning, centuries later, to destroy the settlers who had dared erect homes above their graves.

Do not mistake these multiple trends—the energy flows of metropolitan growth, the new taste for tea, the nascent, half-formed awareness of mass behavior—for mere historical background. The clash of microbe and man that played out on Broad Street for ten days in 1854 was itself partly a consequence of each of these trends, though the chains of cause and effect played out on different scales of experience, both temporal and spatial.

To solve the riddle of cholera you had to zoom out, look for broader patterns in the disease’s itinerary through the city. When health matters are at stake, we now call this wide view epidemiology,

When you read through that endless stream of quack cholera cures published in the daily papers, what strikes you most is not that they are all, almost without exception, based on anecdotal evidence. What’s striking is that they never apologize for this shortcoming. They never pause to say, “Of course, this is all based on anecdotal evidence, but hear me out.” There’s no shame in these letters, no awareness of the imperfection of the method, precisely because it seemed eminently reasonable that local observation of a handful of cases might serve up the cure for cholera, if you looked hard enough.

Over generations, the gene pool of the first farmers became increasingly dominated by individuals who could drink beer on a regular basis. Most of the world’s population today is made up of descendants of those early beer drinkers, and we have largely inherited their genetic tolerance for alcohol.

The descendants of hunter-gatherers—like many Native Americans or Australian Aborigines—were never forced through this genetic bottleneck, and so today they show disproportionate rates of alcoholism.

You have to be a committed libertarian or anarchist to think that the government shouldn’t be building sewers or funding the Centers for Disease Control or monitoring the public water supply.

The first defining act of a modern, centralized public-health authority was to poison an entire urban population.

It’s not just that the authorities of the day were wrong about miasma; it’s the tenacious, unquestioning way they went about being wrong.

He was brilliant, no doubt, but one needed only to look to William Farr to see how easily brilliant minds could be drawn into error by orthodoxy and prejudice.

And so it was with the Broad Street well that the decision to remove the pump handle turned out to be more significant than the short-term effects of that decision.

But science rarely lands such decisive blows,

But as exacting as Cooper’s map was, it ultimately had too much detail to make sense of the story.

It was not the mapmaking technique that mattered; it was the underlying science that the map revealed.

But it is also a measure of continuity: how the very same issues that Snow and Whitehead confronted on the streets of London have returned to haunt us, this time on the scale of the globe and not the city.

It could be as infectious as the influenza bug that swept the globe in 1918, but several times more lethal. And it would find itself inhabiting a planet that was massively more interconnected and densely settled than it was in 1918.

But planning for its emergence makes sense, because if such a strain does appear and starts spreading around the globe, there won’t be the equivalent of a pump handle to remove.