The Blue Death

by Dr. Robert D. Morris

  The medical orthodoxy held that diseases were either epidemic or contagious. The epidemic diseases that had ravaged Europe since the birth of nations included the black plague, typhus, yellow fever, and malaria. Although contagious diseases had the potential to pass from person to person, according to these theories, epidemic diseases did not. Among the most terrifying features of these epidemics was their apparent ability to attack people who had no exposure to the disease. Contagious diseases moved slowly from one person to the next and could be contained by isolation. Epidemic diseases, on the other hand, could move with explosive speed. Quarantine could not contain them.

  The dominant explanation for the cause of these epidemics held that they spread by a poison in the air, a miasma. Only an agent spread by the wind could move with such speed and defeat all efforts to stop it. Gaps in scientific knowledge with respect to the composition of the atmosphere allowed one to imagine the existence of an airborne poison. Malaria even took its name, which translates as “bad air,” from this misconception. More than half a century would pass before scientists understood that the plague, typhus, and malaria rode in on rats, fleas, and mosquitoes, not bad air.

  Cholera, with its demonstrated ability to devastate a wide area in short order, not to mention its apparent ability to slip through the most stringent quarantine, was, by definition, an epidemic disease. Classic medical wisdom held that, as an epidemic disease, cholera could not spread through contagion. In fact in the 1830s the Lancet, England’s leading medical journal, published a series of articles that derided the foolish notion that cholera was contagious.

  John Snow had a problem with this line of thinking. As a young man in Killingworth, he had watched cholera spread from miner to miner and then on to family members. He found nothing compelling in the arguments against contagion. However he had also seen the explosion of disease in Gateshead that occurred suddenly and simultaneously over a wide area. Cholera it seemed was both contagious and epidemic.

  Cholera roamed the streets of London through the fall of 1848, killing at will. During those months, Snow’s probing led him to a crack deep in the foundation of current medical thinking. As he burrowed deeper into that crack, the tired concrete of ancient beliefs began to crumble around him.

  If an airborne poison spread cholera, then that toxin should behave in a manner similar to the toxic anesthetic agents that Snow had been testing with such rigor in his home laboratory. Every gas he had ever tested showed a consistent, predictable dose-response relationship. Every person or animal exposed to a given dose of anesthetic had roughly the same response. But cholera selected its victims from among families living in the same buildings with no apparent regard for the fact that they all breathed the same air. Even when cholera did strike, its severity varied. Half its victims managed to survive the attack, while some died in a matter of hours. Cholera’s cause, whatever it was, acted unlike any gas he had ever seen.

  Advocates of airborne causes also pointed to the pathology of the disease to justify their case. Cholera’s victims, blue and breathless, appeared to have been asphyxiated. To many this seemed to provide clear evidence that cholera struck at the lungs. Snow looked not at how cholera ended, but how it began. In every case the disease attacked the gut first. What if cholera’s agent was not inhaled, but ingested?

  Here however Snow’s thinking hit a wall. Cholera’s choice of targets seemed to have even less to do with the food and drink its victims consumed than with the air they breathed. Some shunned mutton and others avoided vegetables. Some drank only brandy and others drank well water. If an ingested poison caused the disease, that poison had no consistent hiding place.

  Then, as the epidemic stretched toward the winter, John Snow happened on a radical solution. What if a tiny organism, one too small to be seen with the naked eye, caused the disease? Such an organism could hide in any manner of food or drink. More importantly, if an invisible bit of stool found its way into the mouth of a family member or visitor, the process could begin again and the outbreak could continue.

  In a world of stinking privies and foul cesspools, a world where the streets were crusted with manure, rotting garbage, and human excrement, a world filled with things vile, dangerous, and obvious, Snow’s notion that something undetectable could wreak such carnage was among his most radical.

  Snow was steeped in the science of his day and knew well that advances in microscopy had revealed an unseen world of strange creatures. However people seemed able to consume these mysterious “animalcules” with no effect. The medical establishment paid little attention to these insignificant, odorless curiosities. How could something so small have any consequence for humans?

  Snow followed a radical line of thought to counter this objection. He proposed that most of these animalcules were indeed harmless, but some specific types of organisms or at least one type was far from benign. If that specific organism were capable of replicating in the human gut, then perhaps, when its numbers were large enough, it could cause the explosive diarrhea that characterized cholera.

  But Snow’s carefully constructed explanation had a hole. Ingestion seemed to require close contact with a previous victim. This theory left unexplained the explosive outbreaks that struck suddenly over broad areas. Then, in the fall of 1848, John Snow had an idea.

  Few people in London paid as much attention to drinking water as did John Snow. That relationship began with a book. As an apprentice in Newcastle, he came across a copy of Return to Nature or A Defence of the Vegetable Regimen by John Frank Newton. This strange, rambling screed warns of “the dire effects on the human frame of animal food,” drawing on everything from the writings of Cicero to the science of Justus von Liebig to justify a vegetarian diet. As a teenage apprentice, Snow must have found something compelling in the book, for he spent much of the remainder of his life as a vegetarian. This was not a casual undertaking in the unrefrigerated world of Victorian England. The long and literally fruitless winters were bland at best and threatened malnutrition at worst. Still Snow persisted at a time when this peculiar habit made him an object of curiosity.

  Snow rarely did anything halfway and so he took on the book’s other essential dietary advice. Not only was he an ardent and active teetotaler but from the time he first assembled a still in his quarters in Newcastle until the day he died, he drank distilled water. Newton’s book asserted that even ordinary drinking water would undermine the benefits of a vegetarian regimen, primarily because of what he believed to be the routine presence of “animal oils” in drinking water. To Snow’s early mentors, this was the strange and annoying habit of a confused adolescent, but Snow never relented. When he arrived in London, one of his first acts was to set up a still for his drinking water.

  Snow’s use of purified water may have saved his life as he found himself again and again at the epicenter of the cholera epidemic in England. It also offered a rare perspective on the water consumption of his countrymen. Perhaps it was during one of his distillation runs that the idea occurred to him. What if a drinking water supply were contaminated with fecal matter from a cholera victim? The deadly water could spread through a network of pipes and reach the water pitchers of unsuspecting victims over a broad area in a single moment.

  His long string of cognitive leaps had landed on a solution. He did not have to decide if cholera was a contagious or an epidemic disease. It could be both. The dichotomy was a false one and now he had the mechanism to explain it.

  John Snow’s indictment of London’s drinking water was not radical in and of itself. The medical community recognized that dirty water could make you sick. Snow, however, parted ways with his colleagues when it came to how water could make you sick. They held that fermenting organic matter in drinking water could release the same foul-smelling miasmatic poisons that caused epidemics and that these poisons could kill. Certainly, they conceded, drinking straight from the reeking water of the Thames could cause disease and might even spread cholera. Snow’s theory required no s
uch miasma. If his ideas were correct, water with no smell or visible contamination could kill.

  John Snow had enough experience in the arena of ideas to know that a theory resting on so many untested suppositions would not carry much weight among his medical peers. He needed data. In the study of anesthesia, he had been able to conduct experiments to test his hypotheses. In his investigations of the cause of cholera, his superb skills in the laboratory could not give him the data he needed.

  Animal experiments were not an option. Efforts to find the cause of cholera during the first epidemic had included feeding the excretions of cholera victims to a variety of animals. None of them had developed cholera. This was taken as proof that the cause of cholera was not ingested. Snow did not believe this, but had to find a way to disprove it.

  Conducting human experiments was ethically impossible. To do so would have involved assembling two similar groups of people and exposing one group to contaminated water and one to pure water. If his theory was right, many of the subjects would have died in his quest for the truth. Snow could not conduct the trial, but he did have an alternative. He could wait for cholera to conduct the trial for him.

  So Snow had to watch and wait. Cholera’s experiment required a neighborhood with two water supplies. If it contaminated one and not the other, the resulting outbreak would point an accusatory finger at the contaminated drinking water. For Snow to begin to prove his theory, cholera needed to conduct the experiment. Unfortunately the deadly disease was not in the habit of publishing the results of its grim research. Instead, amidst the chaos of the epidemic, Snow would need to find the data.

  Month after month, John Snow sat on his revolutionary idea. He broke his silence only once, when he tested the theory on two trusted colleagues. They listened with interest, but remained unconvinced by Snow’s argument. Their skepticism did not discourage Snow, but it did convince him to wait until he could gather more data before presenting his theory to a wider audience.

  For almost a year Snow’s notion stayed within this small circle. During that year he developed a network of informants to help him track the disease’s every move. As it struck one neighborhood after another, he visited the site of each cluster, talking to the doctors involved and to the survivors. Through the winter and spring, his investigations came up empty. Then in the summer of 1849 cholera showed its hand.

  Cobbled together from pieces of London’s history, the systems that carried water and waste had emerged from the city’s agrarian past, evolving according to the expediency of the moment. There was no master plan and the architects of disaster rushed in to fill the void.

  London’s first residents had relied on the Thames and its tributaries for their water. As the city grew, many residents of London and the farms around it dug wells to find drinking water. Others built cisterns to capture rainwater. With further growth, water companies began to supply piped water, much of it drawn from the Thames. With the help of their friends in Parliament, the water companies carved up the city into districts over which they maintained exclusive control. By 1849 a Londoner might rely on wells, cisterns, piped water, or even buckets of river water. The choice depended on location, income, and personal preference. That choice would come to mean the difference between living and dying.

  London’s system for disposing of wastewater depended on the separation of waste. Feces and urine accumulated in the privies, which were placed at some distance from any residence. No amount of perfume or lime could make a trip to one of these Victorian outhouses palatable. One routinely emerged gasping for breath and praying for constipation. A nighttime trip was to be avoided at all costs, so a portion of the city’s urine was stored under its beds in chamber pots during the night and flung out the window in the morning accompanied by a cry of “Gardez loo!,” a bastardazation of the French “Gardez l’eau,” or “watch out for the water.” Wastewater from bathing, laundry, dishwashing, and household cleaning accumulated in the cesspools where water would seep into the ground and solids would slowly accumulate.

  The guild of night soil rakers not only cleaned the privies or ash pits (euphemistically called because of the practice of spreading fireplace ash on them in an attempt to control odor), but also paid for the privilege as they could resell the valuable fertilizer to farmers on the outskirts of the city. Periodically they also cleaned the waste that accumulated in the bottom of London’s cesspools. The rakers could never come often enough.

  Sewers were intended to drain the streets. As the streets were far from clean, the sewers carried far more than rainwater. Grant’s report on the outbreak at Albion Terrace concluded that the source of the problem was simply the miasma escaping from the rotting organic matter in the sewers.

  The Vibrio cholerae bacterium is a creature that thrives in the warmth and moisture of a human intestine. Once out in the world, it struggles to survive long enough to find another victim. The warm waters of India suited the microscopic killer, helping it to find refuge between pandemics. For most of the year, the cold water of southern England was far less hospitable. Then as the summer sun warmed the Thames, London came to look, from the perspective of cholera, more and more like Calcutta.

  The Surrey buildings, a cluster of small apartments in the dockside district of Horsleydown, drew their water from a well. During heavy rains, the well had a tendency to overflow. When it did the water would wash up onto the street before draining back down into the well. Whatever illness this caused before the summer of 1849 had drawn no notice. In late July of that year however, cholera was so widespread in this poor district on the Thames that two of the buildings’ residents had the disease. Their family members had dumped the wash water from the sheets into the gutter. As the rain fell, it scoured the gutters and Vibrio cholerae poured into the well.

  Eleven people in the Surrey buildings would die from cholera over the two weeks that followed. When Snow investigated and learned of the contamination of the well, he saw it as evidence of waterborne disease. But the residents of the Surrey building were poor; they were expected to die of cholera. The disease was easily found in the surrounding neighborhoods. Even though the rate of disease was far higher in the Surrey buildings, Snow suspected this evidence alone would not prove compelling.

  At almost the same time however, cholera had infiltrated Albion Terrace, a far different neighborhood about a mile upstream and far removed from the squalor of the river’s edge. When John Snow learned that cholera had killed twenty people from a row of seventeen upper-class homes in a matter of days, he rushed to the neighborhood to investigate. Albion Terrace was an island of devastation surrounded by a cholera-free sea.

  During the ten days of the Albion Terrace outbreak, 1,231 people had died of cholera in London, but this outbreak among the affluent had already attracted the attention of the General Board of Health. When Snow arrived, their emissary, an engineer by the name of Thomas Grant, had already begun his investigation.

  The residents had learned to live with flooded basements after each heavy rain. Mr. Grant’s excavations had revealed how cesspools, swollen with rainwater, had overflowed and contaminated the row of interconnected cisterns that served the buildings. He pointed the finger of blame at the resulting stench together with the emanations from an open sewer some four hundred feet away. A miasma, Grant concluded, had caused the disaster.

  When John Snow examined samples that Grant had provided him from two of the cisterns, he reached a far different conclusion. Even before he reached his laboratory, Snow sensed that he had the evidence he needed. As he picked through the foul sludge that Grant had scooped from a thick layer on the bottom of the tanks, he found the peel of a grape.

  Something more than mere wash water had found its way into the drinking water. Unless someone in the building was in the habit of peeling grapes, the empty peel that Snow found had first passed through a human digestive tract. This meant that a bit of privy soil had found its way into the cistern and with it the seeds of cholera.

 
Snow rushed to put his theory to paper. Night after long night, he assembled his case. As he wrote, the undigested bits of food in the specimens from Albion Terrace that sat in his office fermented with such ferocity that the corks would pop out of their bottles on the shelves above him.

  Less than a month after the outbreak, he walked into the office of John Churchill and Sons with a manuscript under his arm. By early September the Soho publisher had provided Snow with a stack of the thirty-one page monograph still smelling of fresh ink. Having conducted the research and paid for its publication, he set to work distributing copies of On the Mode of Communication of Cholera to colleagues and medical journals.

  If Snow had hoped for a quick acceptance of his theory, the response to his monograph was disappointing. Even though the notion that cholera was contagious had grown far more acceptable since 1831, London’s two leading medical journals seemed unimpressed by Snow’s efforts. The review in the Lancet was only two paragraphs long, one of which was simply a quote from the monograph. In this cursory treatment, the editors asserted that Snow’s arguments against an airborne cause were “not by any means decisive.” Recognizing that the review was too short to fully present and rebut Snow’s work, they suggested that their readers refer to the essay, but cautioned that it “must of course be received with great limitation.”

  The London Medical Gazette, London’s other leading medical publication, published a far more extensive, but no less dismissive, review. The review discarded Snow’s analysis of the Albion Terrace outbreak, stating:

  There is, in our view, an entire failure of proof that the occurrence of any one case could be clearly and unambiguously assigned to the use of the water…. Foul effluvia from the state of the drains [i.e., an airborne miasma from the sewers] afford a more satisfactory explanation of the diffusion of the disease.