The Ghost Map

by Steven Johnson

  Whatever the explanation, those few days at the very outset of the epidemic had been a kind of microbial lottery: a population of V. cholerae gathered together in a small pool of water, waiting to be propelled upward into the light of day, where untold possibilities for reproductive glory awaited them. Those that made it out of the pump would go on to generate trillions of offspring in the small intestines of their victims. Those that stayed behind would die.

  When Whitehead later retraced the week’s events, he found even more cases of survivors drinking copious amounts of Broad Street water. He tracked down one boy who had fallen ill and attributed his recovery to his drinking ten quarts; he found a girl who consumed seventeen during her (ultimately successful) attempt to fight off the disease. But he found something else as well in re-creating the outbreak’s chronology: almost all the survivors who had consumed large quantities of Broad Street water did their drinking after Saturday. It was much harder to find anyone who would report drinking the pump water earlier in the week—because most of those people were dead.

  So it is possible that V. cholerae had largely abandoned the pump by the weekend, dying in the dark, cool waters as the outbreak flamed twenty feet above. Perhaps another microbial organism had vanquished the killer on its own. Or perhaps the natural flow of groundwater had slowly cleansed the pump supply and the initial colony of V. cholerae had dispersed through the gravel and sand and clay beneath the streets of Soho.

  BY THE END OF THE DAY, SNOW HAD BUILT A CONVINCING statistical case against the pump. Of the eighty-three deaths recorded on Farr’s list, seventy-three were in houses that were closer to the Broad Street pump than to any other public water source. Of those seventy-three, Snow had learned, sixty-one were habitual drinkers of Broad Street water. Only six of the dead were definitively not Broad Street drinkers. The final six remained mysteries, “owing to the death or departure of every one connected with the deceased individuals,” as Snow would later write. The ten cases that fell outside the imagined boundary line surrounding the Broad Street pump were equally telling: eight appeared to have a connection to Broad Street. Snow had established new causal chains back to the pump water, beyond the list of Farr’s addresses: the proprietor of the coffeehouse who often sold sherbet mixed with Broad Street water told Snow that nine of her customers had died since the outbreak began. He had drawn the telling contrast between the Lion Brewery and the Eley Brothers factory; he had documented the unlikely safe haven of the Poland Street Workhouse. He even had his experimentum crucis in Hampstead.

  It was, on the face of it, a staggering display of investigative work, given the manic condition of the neighborhood itself. In the twenty-four hours since he’d received Farr’s early numbers, Snow had tracked down intimate details of behavior from the surviving family and neighbors of more than seventy people. The fearlessness of the act still astonishes: as the neighborhood emptied in terror from the most savage outbreak in the city’s history, Snow spent hour after hour visiting the houses that had suffered the worst—houses that were, in fact, still under assault. His friend and biographer Benjamin Ward Richardson later recalled: “No one but those who knew him intimately can conceive how he laboured, at what cost, and at what risk. Wherever cholera was visitant, there was he in the midst.”

  It’s unlikely that anyone in London that day had a better sense of the outbreak’s magnitude than John Snow and Henry Whitehead. But ironically, their local knowledge of Broad Street made it hard for them to gauge the true extent of the tragedy. There were at least twice as many Soho residents suffering in a local hospital as there were people dying in the shuttered dark of their own homes. In the three days after September 1, more than 120 cholera patients overwhelmed the staff at nearby Middlesex Hospital, where Florence Nightingale observed that a disproportionate number of the sufferers appeared to be prostitutes. The sick were stacked together in large, open rooms, and treated with saline and calomel. The air was thick with the smell of chlorine and sulfuric acid that the staff had scattered around the sickrooms in large dishes, ostensibly to purify the air. It was ultimately of little use: two-thirds of the patients died.

  When the number became too great to house at Middlesex, new arrivals were sent to the University College Hospital. Twenty-five cholera patients arrived in the first three days of September. Westminster Hospital had admitted eighty patients in the first few days of the outbreak. Other institutions saw notable influxes: by that Wednesday, more than fifty cholera patients had been admitted to Guy’s, St. Thomas’, and Charing Cross hospitals.

  St. Bartholomew’s Hospital had received the most cholera patients—almost two hundred in the first days of the outbreak. The physicians there experimented with multiple treatments, with varying degrees of success: castor oil, capsicum, even cold water. An intravenous injection of a saline solution designed to mirror the salinity of blood serum appeared to revive two patients, but they died hours later—most likely because, like Thomas Latta’s patients in 1832, they were not given multiple injections.

  And so the devastation in the streets above Golden Square was, in truth, only a fraction of the story. As Snow and Whitehead made their calculations that Wednesday, they were still thinking in double-digit figures. They would soon discover that those numbers were shockingly optimistic.

  IT IS POSSIBLE SNOW’S INTENSE ROUND OF QUESTIONING may have, on its own, diminished the spread of the epidemic. We know from Snow’s own account that he spoke with hundreds of people in the neighborhood over the course of the week, and that most of those conversations involved questions about the Broad Street pump. What we don’t know is whether Snow betrayed his theory of the cholera’s source in those conversations. Were they both interviews and warnings? Snow was a physician, after all, and the poor, frightened inhabitants of Soho were his patients. If he believed that the pump was spreading fatal disease, it seems unlikely that he would have kept that information to himself. Would a hundred separate warnings from an esteemed physician be enough to suppress the neighborhood’s taste for Broad Street water? The most dramatic drop in deaths had occurred on Tuesday and Wednesday—two days after Snow began exploring the neighborhood. Perhaps fewer people were dying because some portion of the population had heard a rumor that the pump was to blame.

  But if the epidemic was in decline, it was still at terrifying levels by any normal standard. Snow knew from his investigative rounds that at least a dozen new deaths had occurred that Wednesday—ten times the normal rate for the neighborhood. Given the exodus of the population, it was possible that the plague was still every bit as deadly, on a per capita basis. He knew his statistical account of the outbreak would be a convincing argument for his waterborne theory, particularly when it was accompanied by the final results from his South London waterworks study. His monograph on cholera would have to be revised, new articles submitted to The Lancet and the London Medical Gazette. But in the short term, there was a more pressing matter at hand. People were still dying in his neighborhood, and his survey of the outbreak clearly revealed the culprit.

  “DEATH’S DISPENSARY”

  Friday, September 8

  THE PUMP HANDLE

  ON THURSDAY NIGHT, THE BOARD OF GOVERNORS OF ST. James Parish had held an emergency meeting to discuss the ongoing outbreak and the neighborhood’s response. Halfway into the meeting, they received notice that a gentleman wished to address them. It was John Snow, armed with his survey of the past week’s devastation. He stood before them, and in his odd, husky voice told them that he knew the cause of the outbreak, and could prove convincingly that the great majority of cases in the neighborhood could be traced to its original source. It is unlikely that Snow went into the intricacies of his broader case against the miasma theory—better to go straight to the telling patterns of death and life, leave the philosophizing for another day. He explained the dismal ratios of survival among the people living near the pump, and the unusual exemptions granted to people who had not drunk the water. He told the Board of Governors of
deaths that had transpired far from Golden Square, connected to the area only by the consumption of Broad Street water. He may have told them of the brewery of the workhouse on Poland Street. Death after death after death had been linked to the water at the base of the Broad Street well. And yet the pump remained in active use.

  The members of the Board were skeptical. They knew as well as any other locals how highly regarded the Broad Street water was—particularly as compared to the other nearby pumps. But they also knew firsthand the smells and noxious fumes that were rampant in the neighborhood; surely these were more responsible for the outbreak than the reliable Broad Street water. Yet Snow’s argument was persuasive—and, besides, they had few other options. If Snow was wrong, the neighborhood might go thirsty for a few weeks. If he was right, who knew how many lives they might save? And so, after a quick internal consultation, the Board voted that the Broad Street well should be closed down.

  The following morning, Friday, September 8, exactly a week after the outbreak had first begun its awful rampage through Soho, the pump handle was removed. Whatever menace lay at the bottom of the well would stay there for the time being.

  The deaths in Soho would continue for still another week, and the final reckoning of the assault of the Broad Street well on the neighborhood would not be calculated for months. The removal of the pump handle was generally ignored by the newspapers. On Friday, the Globe had published an upbeat—and typically miasmatic—account of the present state of the neighborhood: “Owing to the favourable change in the weather, the pestilence which has raged with such frightful severity in this district has abated, and it may be hoped that the inhabitants have seen the worst of the visitation. Yesterday there were very few deaths, and this morning no new cases were reported.” On the following day, however, the news appeared to be less encouraging:

  We regret to announce that after the account was written which appeared in The Globe of yesterday, there were several severe and fatal cases of cholera, and that seven or eight were reported on Saturday morning, although the wisest precautions were adopted to arrest the progress of the disease. The neighbourhood of Golden-square presented… a most melancholy and heart-rending appearance. There was scarcely a street free from hearses and mourning coaches, and the inhabitants of the district, appalled by the calamity which has visited them, crowded the streets to witness the last sorrowing act of duty towards their neighbours and friends. A vast number of the tradespeople left their shops and fled from the place, the closed shutters bearing the announcement that business had been suspended for a few days. Messers Huggins, the brewers, with praiseworthy forethought, have issued an announcement that the poor… may obtain any quantity of hot water for cleansing their dwellings, or other purposes, at any hour of the day or night, an act of humanity and kindness of which a large number have availed themselves.

  Dozens would die over the next week, but clearly the worst was over. When the final numbers were tallied, the severity of the outbreak shocked even those who had lived through it. Nearly seven hundred people living within 250 yards of the Broad Street pump had died in a period of less than two weeks. Broad Street’s population had literally been decimated: ninety out of 896 residents had perished. Among the forty-five houses extending in all directions from the intersection of Broad and Cambridge streets, only four managed to survive the epidemic without losing a single inhabitant. “Such a mortality in so short a time is almost unparalleled in this country,” the Observer noted. Past epidemics had produced higher body counts citywide, but none had killed so many in such a small area with such devastating speed.

  THE REMOVAL OF THE PUMP HANDLE WAS A HISTORICAL turning point, and not just because it marked the end of London’s most explosive outbreak. History has its epic thresholds where the world is transformed in a matter of minutes—a leader is assassinated, a volcano erupts, a constitution is ratified. But there are other, smaller, turning points that are no less important. A hundred disparate historical trends converge on a single, modest act—some unknown person unscrews the handle of a pump on a side street in a bustling city—and in the years and decades that follow, a thousand changes ripple out from that simple act. It’s not that the world is changed instantly; the change itself takes many years to become visible. But the change is no less momentous for its quiet evolution.

  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. Yes, the Broad Street outbreak would burn itself out over the next few days, as the last victims died off and other, more fortunate, cases recovered. Yes, the neighborhood would slowly return to normalcy in the weeks and months that followed. These were real achievements that arose from that pump handle being removed, even if the water in the well had potentially been purged of V. cholerae by the time Snow made his case to the Board of Governors. But the pump handle stands for more than that local redemption. It marks a turning point in the battle between urban man and Vibrio cholerae, because for the first time a public institution had made an informed intervention into a cholera outbreak based on a scientifically sound theory of the disease. The decision to remove the handle was not based on meteorological charts or social prejudice or watered-down medieval humorology; it was based on a methodical survey of the actual social patterns of the epidemic, confirming predictions put forward by an underlying theory of the disease’s effect on the human body. It was based on information that the city’s own organization had made visible. For the first time, the V. cholerae’s growing dominion over the city would be challenged by reason, not superstition.

  But learning to listen to reason takes time, particularly among the general public of Broad Street, who had heard nothing but superstition from the authorities for as long as cholera had been in London. When the Board of Governors removed the handle on Friday morning, the act was met with open jeering and derision by the passersby who chanced to witness it. Their bafflement is not hard to understand. For many survivors, Broad Street water had been their primary medicine. And now the authorities were going to cut off the supply? Were they trying to wipe out the entire neighborhood?

  It was not just the Soho locals who were deaf to Snow’s reason. The very day that the local Board of Governors removed the handle, the president of the national Board of Health, Benjamin Hall, issued directives for the three-man committee he had formed to investigate the Broad Street outbreak. The inspectors were asked to perform a house-to-house survey through the entire neighborhood and report back on a long list of environmental conditions. It is worth quoting the directives in their entirety, since the list captures perfectly the miasmatic obsessions of the Board of Health:

  Structural peculiarities of the Streets as regards Ventilation.

  Nuisances, slaughter-houses, noxious trades, etc.

  Smells in the streets and their source, gully grates, gutters, etc; whether the gully grates trapped, whether cases and deaths more numerous in houses near gully grates.

  Smells in houses and their source, such smells worse during the night, or in the morning before the houses or shops were opened.

  Whether the house had privy, or water-closet or cesspool and the position of these; whether complaints of smells from them; whether they were in good condition; whether the water-closets were well supplied with water; whether the house drainage stopped.… This district has been lately drained. Ascertain how many of the houses have drains connected with the new sewers; whether the house drains pass under the house to reach the sewer; the structure of the house drains, pipe or brick drains, and their condition; whether subject to stoppage, or smells from them.

  Examine the basements as to the depth of the floor below the level of the street; whether there had been any accumulations of house refuse in these basements, or in the adjoining cellars before the outbreak. Consider the effect of these conditions on the general ventilation of the house, especially at night….

  Examine the houses as to their general clea
nliness and means of ventilation. Examine also the back yards, and inquire what was their condition before the epidemic. Note if they be flagged or filthy.

  Examine whether the disease occurred in the upper or lower flats. Get, if possible, the proportion of cases in the flats.

  Estimate as closely as you can the condition of the inhabitants as to overcrowding, personal cleanliness, habits, diet, etc.

  Get the number of cases in each house, and the number of deaths of persons who lived in each house.

  Examine the water supply as to its source, quality, amount, whether drawn from pipes or water-butts, and the condition of the butts.

  Note the general condition of the streets and courts, and inquire what was the state of the cleansing before the outbreak.

  Examine whether the disturbance of the ground in making a sewer through the old burial ground in Little Marlborough Street, or the filtrations from it into the sewer, or the drainage of any nuisance into the general sewerage of the district had had any effect, or whether the sewers had accumulations in them that might have been injurious.