The Blue Death

by Dr. Robert D. Morris

  At first John Snow was not sure how he would sort out this puzzle. He brought water from each supplier to his laboratory to test, hoping he could find an answer. He had already noticed that when he held the vials of water up to the light, that he could see fine particles swirling in the S&V water, but this was not enough. The particles might settle out if the water had sat in a cistern. On a given day, they might be less prevalent. Even the Lambeth water could become cloudy if it had sat in a dirty cistern or had run through dirty pipes. John Snow needed certainty.

  After five years of looking for the data that would prove water’s capacity to kill, he sensed he had found the critical evidence. He could not let himself be thwarted by something so simple as the incomplete knowledge of the study subjects. But if he could not find a way to distinguish between the different water supplies, the results of that experiment would remain unrecorded. Finally John Snow had an idea.

  That long tongue of seawater carried the answer to his problem. Salt. Snow took a gallon of water from each supplier to his laboratory. He pulled a bottle of silver nitrate solution from the shelf and added an equal amount to each sample. As he did so, a cloud formed in the water. The silver was combining with the chloride from the salt to form insoluble particles of silver chloride. Today high school students routinely perform this experiment, but in 1854 this was state-of-the-art analytical chemistry. When he dried the crystals from each sample, his problem evaporated as well. The S&V water, being closer to the mouth of the Thames and the tidal flows upstream, contained forty times as much salt as the Lambeth water from Thames Ditton. If he performed a similar test on his samples, he would know the source of their water with absolute certainty.

  Forty-four times John Snow knocked on the doors of cholera victims in Kennington. Forty-two times he obtained a receipt or a water sample. (Two homes relied on pump wells for their water.) As he tested each water sample for salt and began to accumulate data, the results were astonishing. Ninety percent of the cholera victims got their water from S&V.

  In the course of his walking tour from home to home, he had recognized something else remarkable. Nothing about the homes he visited allowed him to predict the water supply. There seemed to be no pattern to the distribution system. He had stumbled on a population that had received either water contaminated with sewage or pure water almost at random. The customers of the different water suppliers differed only with respect to the water they consumed. Otherwise they were as similar as two cages of laboratory guinea pigs. The war of the water companies had eliminated confounding. John Snow had found his experimentum crucis.

  But he had only looked at a part of the experiment. He had looked at two subdistricts over a few weeks of the epidemic. Chance had performed this experiment on more than 300,000 people and would continue to do so as the death toll mushroomed. Such an important experiment needed to be recorded in full, but such an undertaking was far beyond his means. He needed help, but where could he go?

  Snow could think of only one place. Only one group in England had the resources to gather this critical data. But that group was lead by an ardent sanitarian. He might well scoff at Dr. Snow and his wild ideas about water. Snow had to take that chance.

  John Snow rushed to the Office of the General Registrar to talk to William Farr. Farr had pioneered the collection and use of data on death and its causes and had given Great Britain the world’s best vital statistics registry. No one respected the power of these data more than Farr. Despite Farr’s belief that cholera emerged from low-lying miasmas rather than water, he saw in Snow a kindred spirit. The two men had helped found the London Epidemiological Society and saw each other regularly at its meetings. When he saw Snow’s data, he too was astonished.

  In response Farr himself suggested that the registrars of the south districts of London should determine the water supply for all homes in which a death occurred from cholera. After years of solitary research, Snow finally had an ally.

  Still Farr’s order would only cover deaths that occurred after August 26. Snow had studied deaths through August 12 and only in a portion of the subdistricts supplied by the two companies. Snow was determined to gather all possible data. He would need to expand his study to include all sixteen subdistricts and two additional weeks during which cholera mortality had risen explosively. That meant he would need to visit the homes of more than a thousand cholera victims. He would need help. And time.

  The earnings from his burgeoning medical practice allowed him to hire John Joseph Whiting, an apothecary, to assist in the study. For the first and only time in his career, John Snow had a research assistant. He assigned Whiting to visit homes in the districts served only by S&V. In that way Whiting would only need to determine whether or not the victim had used piped water, well water, or water from some other source such as tidal ditches. Snow would take on the more difficult task of determining the water supply used by victims in subdistricts served by both suppliers.

  He had set aside the first two weeks of September to complete his task. And so Dr. John Snow, anesthetist to the queen, prepared to walk the streets of South London, visiting hundreds of homes and collecting and analyzing vast numbers of water samples to determine the source of their drinking water. Just as he began this daunting task, cholera came to his doorstep.

  5

  THE DOCTOR, THE PRIEST, AND THE OUTBREAK AT GOLDEN SQUARE

  As an oppressive blast of late summer heat bore down on the estates of Hampstead, just north of London, Susannah Eley, a wealthy widow, was enjoying a visit from her niece. For almost the whole of August, England had baked under clear, motionless skies. What breeze there was carried in a blanket of thick, humid air laced with the fetid breath of London. As that last, cloudless day of the month wore on, the two ladies sipped from their water glasses in the sweltering heat.

  They found nothing disagreeable in the taste of the water. It gave off no foul odor, nothing to suggest the presence of a disease-causing miasma. If either of them had looked closely, she might have seen a few fine white particles drifting in her glass, but in 1854 this was no cause for alarm. What possible harm could come from particles they could barely see? They had no reason to believe that death could come in such a small package.

  The same heat that made the widow Eley and her niece uncomfortable made London’s inner city unbearable. Day after day the sun had slowly roasted the city’s noxious accumulation of human and animal waste. Each neighborhood had its own special topography of odor that rose and fell with the temperature. On a cool day, the terrain was challenging, but negotiable. In the heat of summer, the city’s residents struggled to find a path through these mountains of stench.

  For Londoners who lived or worked among the dense jumble of residence and commerce between Golden Square and Soho Square on London’s East End this assault on the senses was unrelenting. At the street level, every manner of business and industry from breweries to slaughterhouses produced a full spectrum of offense. To this mixture stables, decrepit privies, and ancient cesspools added their own offerings, sending an unrelenting stink steadily up toward the homes of the working poor who crowded into tiers of one-room apartments above the street.

  When the heat was less intense or the air less still, those who lived and worked on these dark and narrow streets might find a mouthful of untainted oxygen in the open expanse of Golden Square or on the few wide streets such as Marlborough or Broad, but they provided no such haven on that Thursday. As the heat grew on that last day of August, the vile reek of the privy outside the Newcastle-on-Tyne Pub at the corner of Cambridge and Broad laid siege to the four-story tenements next door. The residents crowded into the rooms above the boot tree maker on 40 Broad Street could either close their windows and swelter in the stultifying heat or open them and surrender to the putrid assault.

  In one of those rooms, Susan Lewis, the wife of a policeman, anxiously prepared a bottle of rice meal and milk. In a world that did not understand sanitation, bottle-feeding often meant disease and ev
en death for an infant, but Susan Lewis had no choice. An illness late in pregnancy had left her unable to breast-feed her infant daughter. The baby had now fallen seriously ill for the third time in her five short months of life. The attack of diarrhea, which had begun just four days earlier, had subsided, but it had left her weak with no appetite. Mrs. Lewis tried to stir her baby, offering the bottle and hoping she would eat. Instead the frail infant lay passively, taking nothing. Three years earlier Susan Lewis had lost her son before he reached his first birthday. Now the young mother feared the worst.

  Two doors down workers at the Eley Brothers percussion cap factory replenished two large cisterns with water from the pump just outside their doors on Broad Street. In the heat the owners made sure to refresh their workers’ water supply regularly. They had recently noticed that the water tended to develop an offensive odor after sitting for more than two days, so they were particularly diligent in this task.

  That morning workers at the factory had also filled a large bottle with water from the pump and packed it on a cart bound for the West End. For reasons lost to history, the Eley brothers’ mother preferred the water from the pump to that from wells far closer to her home. Perhaps she requested water from Broad Street out of some sort of affection for her late husband who had owned the factory until his death. Perhaps she simply preferred the taste of its water.

  Whatever the reason Susannah Eley’s sons sent a cart laden with drinking water from the Broad Street Pump on its routine trip. Several times each week, the cart would make its way through the crowded streets of London, past the farms that surrounded the great city and out to Hampstead, a distance of four miles, to deliver a large bottle of water and, in the late summer of 1854, cholera.

  As night fell on the lingering heat of that cloudless summer Thursday, the widow Eley and her niece drank the water from Broad Street, oblivious to the disaster that lay ahead. They could not have imagined that each of the minuscule particles suspended in the innocence of drinking water contained millions of deadly comma-shaped bacteria, the telltale form of Vibrio cholerae. That night the strong acids in the widow’s stomach destroyed almost all these microscopic invaders and might have saved her had they not been so numerous. The massive dose in each glass of water ensured that some of the bacteria would find their way through her stomach to the haven of her small intestine.

  The hydrochloric acid that had dissolved her evening meal packed the corrosive power of battery acid. In addition to destroying most of the bacteria, it would have eaten through the walls of her stomach were it not for the thick protective slime secreted from its lining. This coating worked well for the crude operations of the stomach. The small intestine had a far more intricate task. It would need to break down the nutrients in the slurry of food passing through its thirty-foot length and transport them molecule by molecule into the widow’s bloodstream. Any protective layer would make this impossible. Instead specialized cells released just enough bicarbonate to neutralize the acidic mixture flowing from her stomach to protect the delicate lining of her small intestine. That night the bicarbonate also granted a reprieve to the cholera.

  As the night wore on, the few surviving bacteria had already begun to reproduce inside her. When she awoke their numbers were still so small that Susannah Eley had no notion of the danger at hand. Back on Broad Street, however, disaster had already begun to rear its head.

  Homes throughout the neighborhood had spent a night in sheer terror as family members plummeted into the abyss of cholera. On the morning of Friday, September 1, as the people of Soho stepped outside, they found that a cooling breeze had arrived from the northeast, but something far worse than a heat wave had arrived in the dark of night. Word of the horror buzzed through the neighborhood. Almost everyone, it seemed, knew someone who was dying.

  No one understood the scope of the disaster better than Reverend Henry Whitehead, the priest of St. Luke’s Church, which stood just one block from Broad Street. Throughout the previous evening and into the night he had walked the streets of his parish in long, flowing robes ministering to the afflicted and their families. For many the appearance of his broad, friendly face gave them a moment of reassurance in an otherwise desperate night. When he finally made his way home through the dense mix of mist and coal smoke to the small apartment that he shared with his brother, he sensed he was facing a devil unlike any he had encountered in his twenty-nine years. He would spend much of the next day delivering last rites to the dying.

  Word of the emerging tragedy had yet to reach the affluent district just across Regent Street where John Snow had immersed himself in a study of the London water supply. His office was filled with maps, death records, and the data he had assembled over the preceding year on the relationship between water supply and cholera deaths in an area south of the Thames. He had recently cut back on his clinical work so he could devote even more time to his experimentum crucis. So as the morning of Friday, September 1, arrived, he was simply relieved that the heat wave had broken.

  After six years of struggling to convince the medical establishment that drinking water could spread cholera, John Snow felt he was finally closing in on the proof that might muffle his critics. The ground itself would need to shake to divert his attention from the task at hand. He would soon discover that an epidemiological earthquake like no other had its epicenter on the north side of the Thames, just a short walk from his front step.

  But as the sun rose on that Friday morning, John Snow had no notion of the horrifying turn of events so close to the desk where he sat piecing together the story of the London water supply. He could not see the first black, windowless carriage as it appeared from behind the curtain of fog that the cool air had draped across Broad Street. He could not hear the horses protest as its driver, also dressed in black, pulled at their reins, bringing the carriage to a stop in front of a four-story building. Two men climbed down and entered the front door with a stretcher. They climbed to an apartment marked by a row of shuttered windows. Minutes later they emerged carrying a draped, lifeless figure. Before they had finished loading the corpse into the back of their carriage, the sound of hoofbeats and steel-rimmed wheels signaled the arrival of another crew with the same grim mission.

  Over the course of that day, a fleet of hearses rolled steadily through the district. Again and again these faceless wagons came to collect their tragic cargo. More than sixty people living in the area around Broad Street died on that Friday. As each hearse arrived, neighbors watched, quietly registering the address of the deceased and wondering where the next would stop.

  But the worst was yet to come. Throughout the day the blue death roamed the district, visiting one home after another, selecting its next victims with an apparent randomness that was both cruel and terrifying. As word spread of each new case, fear grew palpable. Those who rented furnished rooms and did not have a friend or relative in need of their care packed up their belongings to seek refuge elsewhere. Before Friday found its end, 143 more people were fatally ill. Still the ravages of cholera were just beginning.

  Of those to whom cholera had laid siege on that Friday, all but two lived within a few blocks of the Broad Street pump. To reach these last victims, however, the disease had traveled to the comfortable homes of Hampstead. There, far from her deceased husband’s Broad Street factory, Susannah Eley began to feel a vague discomfort.

  The bacteria in her small intestine had spent much of the day doubling and redoubling. As the Vibrio cholerae multiplied, they busily manufactured a deadly poison. The toxin targeted the switches in the lining of the intestine that controlled the flow of bicarbonate, jamming them into the “on” position. Susannah Eley could not notice the initial trickle of fluid that seeped into her gut. But as the numbers of bacteria grew, vast quantities of bicarbonate began to flow into the widow’s small intestine.

  By hacking into the signal pathways of her digestive system, the bacteria created a surging torrent of acid-neutral fluid, full of nutrients in which they
could grow and reproduce. What had been the machinery of digestion became a factory for the production of billions upon billions of pathogens that rode the flood of bicarbonate out into the world in search of other victims. It was not the bacteria, but the river they created that would kill her.

  As the first day of September tumbled into darkness, cholera tightened its grip on Broad Street. Early on Saturday the parade of hearses began again. Throughout the day they arrived with increasing frequency, each one departing laden with its grim payload. Late in the afternoon, one arrived at 40 Broad Street. It carried off a tiny corpse and left Susan Lewis consumed with grief over the death of her second child.

  Even in a city that had learned to live with cholera, a disaster of this intensity attracted notice. By Sunday, September 3, word had spread through London. When the news reached the office on Sackville Street where John Snow was untangling London’s complex network of water supplies, it found the one person who could understand what had happened.

  In the mind of Snow, only drinking water could cause such a sudden explosion of cholera. He also knew that two water companies supplied piped water to the area affected by the outbreak; the Grand Junction Company supplied the western portion near Golden Square and the New River Company supplied the eastern portion near Soho Square. Not only did both companies have relatively clean sources of water, they drew from entirely different rivers. The simultaneous contamination of both sources defied probability. More important, Snow knew that anything involving these companies would have affected a much larger area than the highly localized disaster at hand.

  As he gathered his hat and stepped out into the fading heat of summer, John Snow felt certain that the “morbid matter” that caused cholera had made its way from a victim of the disease and into some single, common source of water. He reasoned that a contaminated public well must have given rise to the outbreak.