Source: Wall Street Journal, October 21, 2006.

BOOK REVIEW

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

by Steven Johnson Riverhead Books, New York, 2006. ISBN: 1594489254.

Lost in a Time of Cholera

How a doctor's search solved the mystery of an epidemic in Victorian London

By Ferdinand Mount

Mr. Mount is the author of "Jem (and Sam)" and "Fairness." He was editor of the Times Literary Supplement 1991-2002.

The sociology of error is a wonderful subject. Some university ought to endow a chair in it -- and then make Steven Johnson the first professor. Mr. Johnson last provoked the public with his counterintuitive polemic "Everything Bad Is Good For You," in which he argued that TV and videogames actually improve our cognitive skills. In "The Ghost Map" he tells the story of how for 30 years and more the medical establishment in Victorian London refused to accept what was staring them in the face, namely that cholera was a waterborne disease.

Thousands of Londoners died while doctors and public-health officials stubbornly clung to the view that the plague was an airborne miasma that hung in the foul atmosphere of the slums and was inhaled by the wretched creatures who lived there. Every kind of cure was proposed: opium, linseed oil and hot compresses, smoke, castor oil, brandy -- everything but the simple, obvious remedy of rehydration, which reduces the otherwise fatal disease to a bad case of diarrhea.

The fact that the cholera toxin tricks the cells in the lining of the colon into expelling water at a terrifying rate (victims have been known to lose 30% of their body weight in a matter of hours) should surely have alerted someone to the possibility that putting this Niagara back into the body might be worth trying. Only one doctor, Thomas Latta, hit upon the answer, in 1832, just a few months after the first outbreak ever in Britain. His mistake was not to inject enough salty water, and his lone initiative was soon overwhelmed by the brainless babble of the quacks.

Chief among the villains of Mr. Johnson's unputdownable tale was the man whom we were brought up to revere as the father of public sanitation, Edwin Chadwick (see picture). This dour, tactless, unpopular reformer laid the foundations for all the government interventions in public health that we now take for granted. Yet in this story he labored under not one but two illusions that proved catastrophic.

The first was his belief that, since the mephitic odors of private cesspools posed such a clear and present danger to health, sewage ought instead to be discharged down public drains into the Thames, from which most Londoners took their drinking water. As the great builder Thomas Cubitt remarked: "The Thames is now made a great cesspool instead of each person having one of his own."

The consequences of this well-intentioned blunder were worse even than those of the decision of the Lord Mayor during the Great Plague of 1665-66 to exterminate all the city's dogs and cats because of the false rumor that they were spreading the plague, thus allowing an exponential increase in the population of the rats who were the real transmitters.

Having contaminated a large part of the population he was trying to protect, Chadwick committed his second mistake, sternly setting his face against the simple explanation that would bring about a cure. To his dying day -- which did not come until 1890 -- Chadwick remained an unrepentant miasmatist, as proponents of the airborne explanation for cholera were known. So was Florence Nightingale. The Lancet, the leading medical journal, venomously denounced the waterborne theory and its dogged proponent, John Snow (see picture).

With the austere teetotaller and vegetarian Dr. Snow and his devoted helper in the Soho slums, the Rev. Henry Whitehead, "The Ghost Map" gains not one but two heroes. Patiently they mapped the patterns of victims and survivors and narrowed down the most likely source of the cholera plague to the Broad Street pump. But even after the pump handle was removed so that Londoners could no longer fill their buckets there and the illness subsided, the miasmatists were not convinced. Snow then tramped the streets of Battersea and Vauxhall to demonstrate that those who had their water from higher up the Thames, above the reach of the tide, remained unharmed, while those who took it from the foul tidewater perished in the hundreds. This was no easy task, since the pattern of water pipes under London's houses was as tangled as the pattern of Internet service providers are today.

Why did it take so long? Because mapping epidemics was only in its infancy, though Snow's famous map was not quite the first. Because the questions that Chadwick's public-health board researched were self-fulfilling, all having to do with the smells and personal habits of the poor and not with the water they drank. The researchers mistook correlation for causation: Nobody died on the high ground of Hampstead, where the air was purer, therefore higher was safer -- or so it seemed until a Mrs. Eley, who had retired thither, arranged to receive a jugful of water from her beloved Broad Street pump and got cholera.

But above all Chadwick and his crew were certain of themselves because the stench of the slums was so utterly disgusting and because smell acts so powerfully on our imaginations. Only the most careful and dispassionate investigators were free of the obsession with stench. Henry Mayhew, for example, noted in his "London Labour and the London Poor" (1851) that sewer-hunters, who scavenged deep underground knee-deep in muck, lived to a ripe old age. The Great Stink of 1858, which finally persuaded the government to commission Sir Joseph Bazalgette to lay down the magnificent network of sewers that have lasted to this day, did not kill a single Londoner -- yet still Chadwick did not believe.

This is a marvelous little book, based to a large extent on the essays delivered to an academic colloquium, just as was Dava Sobel's "Longitude" (1996). Yet "The Ghost Map" is a far more ambitious and compelling work. What Mr. Johnson shows us is that the crucial test of a mega-city is whether it can digest its own waste. That whole vagabond London crew of scavengers, bone-pickers and rag-gatherers were not just pitiable victims of the System. In providing their unofficial janitorial services, as Mayhew perceived so well, they were "engaged on one of the most important of social operations" and deserved respect as well as sympathy. Victorian Londoners depended on them as utterly as they (and we) depend on the incessant operation of zillions of microbes.

Mayhew -- the third hero of this book -- saw clearly how our cities, like our bodies, are constantly decomposing and recomposing. The mega-city is in fact something like a natural organism, which begins to fail when one link in the chain breaks. In the case of London's cholera epidemic, the breakdown occurred when a certain class of cleaners, the sewage removers known as night-soil men, found that they could charge as much as one shilling for emptying each cesspit. The poor and their more unscrupulous landlords left the sewage to overflow into the cellars -- and ultimately to leak into the Broad Street well.

Snow had the precious gift of consilience -- "jumping together" (the term was invented by the Victorian historian of science William Whewell and revived by the biologist E.O. Wilson). That is, he could bring side by side techniques or theories from two different disciplines to make a further leap forward. His microscope was not powerful enough to see the comma-shaped cholera bacillus; his only instrument was statistical -- the analysis of the weekly bills of mortality. But his greatest asset of all was a clear head unclouded by preconceptions about the moral and physical squalor of the poor.

Steven Johnson ends by branching out into wider speculations. The density of cities is, he argues, a virtue rather than a defect, except when it comes to suicide bombers. New York is the greenest city on earth, because its jam-packed citizens consume so little energy per head. Mr. Johnson is never less than lively and beguiling in these closing chapters, but for me the image that lingers is that of the tireless Dr. Snow and the Rev. Whitehead padding round the streets of Soho night after night, asking every householder and passer-by the innocent but fateful question: "Where do you get your water from?"

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