Breakthrough!: How the 10 Greatest Discoveries in Medicine Saved Millions and Changed Our View of the World - Jon Queijo (2010)

Chapter 2. How Cholera Saved Civilization: The Discovery of Sanitation


The largest delta in the world is a vast labyrinth of swampy waterways, tall grasses, mangrove forests, and brackish water. Formed from the Ganges and Brahmaputra rivers, it drains through 40,000 square miles along southern Bangladesh and a small corner of India before emptying into the Bay of Bengal. But the Ganges Delta is not merely large: It is also one of the most fertile regions in the world, churning with an enormous variety of life, from microscopic plankton to walking cat fish, from parrots, pythons, and crocodiles to the endangered Bengal tiger. In 1816, two somewhat less exotic life forms intermingled and formed a relationship that would quickly explode into deadly and global proportions. Within 15 years, it would kill thousands of people as it marched through India, parts of China and Russia, and into Europe. In October, 1831, it arrived on the northeast coast of England and quickly began to spread...

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On December 25, 1832, John Barnes, an agricultural worker from a village 200 miles north of London, received what may be the worst Christmas present of all time. It was a box from his sister, who lived 22 miles away, in Leeds.

Barnes opened the box. It was not really a Christmas gift, and it’s not clear whether Barnes was expecting what he found inside: They were clothes that had belonged to his sister, who had died two weeks earlier. As she had no children, the clothes had been dutifully packaged and sent to Barnes. Perhaps Barnes picked up the clothes and contemplated them for a few minutes, fondly recalling when he last saw her wearing them at a family gathering. Perhaps his wife held them up to herself to see if they would fit. In any case, before sitting down to dinner, both noticed something odd about the clothes: They hadn’t been washed. By the time they had finished eating, nothing could stop what was to come next.

The next day, Barnes developed severe cramps and diarrhea. For two more days, the diarrhea was so severe that it did not let up. By the fourth day, Barnes was dead.

Shortly after Barnes had fallen ill, the same malady struck his wife. Her mother was notified, and she rushed to her daughter’s assistance from a nearby village. Although Barnes’ wife survived, her mother was not so lucky. After spending two days with her daughter and washing her linen, she left for home, just a few miles away. Somewhere along the road, she collapsed and was brought back to her village, where her husband and daughter were waiting.

Within two days, the mother, her husband, and her daughter were all dead.

In one sense, the deaths were no mystery. Local physicians recognized that the family had been stricken by cholera, the same disease that had broken out in England in the past 12 months. But in another sense, the deaths were nothing but a mystery. How could two families be stricken so suddenly and fatally when, until their deaths, no one in either of their villages had contracted the disease? Even the discovery that Barnes had received the unwashed clothes from his sister—who herself had died of cholera—shed little light on the mystery. After all, everyone knew at that time that cholera could not be transmitted in this way. With the discovery of pathogenic bacteria decades away, it was presumed—as it had been for centuries—that most disease was caused by inhaling miasma, the invisible particles released by decomposing organic matter, which might include anything from marshy waters and sodden ground, to garbage pits, open graves, and volcanic eruptions.

Yet one visionary doctor of the time did understand the significance of the Barnes story when he heard it. And though leading physicians would stubbornly reject the views of John Snow for the next half-century, he would ultimately not only be proven right, but would play a key role in the greatest medical breakthrough in history.

The Industrial Revolution: a new world of jobs, innovation—and spectacular filth

In 1832, the city of Leeds, like many cities in Europe and the United States, was beginning to experience everything both wonderful and terrible about the Industrial Revolution. In just a few decades, bucolic pastures, rolling hills, and woodlands had been transformed into brick-lined landscapes of textile mills and factories, their tall chimneys proudly puffing smoke into the newly urban skyline. But even as expanding industry generated new jobs and money, it also meant that more people—a lot more people—were flooding into cities to seek their fortunes. In just 30 years, the population of Leeds had more than doubled, creating housing problems never before seen on this scale: Thousands of workers and their families were literally being crammed into small rooms, overcrowded buildings, and jam-packed neighborhoods.

If it is unpleasant to imagine how such growth might strain a city’s infrastructure, try imagining the impact before urban infrastructure had even been invented. For centuries prior to the Industrial Revolution, human waste from households and businesses was commonly disposed of in backyard pits, nearby alleys, and streets. From there, it was periodically removed by “night soil” workmen or scavengers who sold it as fertilizer or for consumption by pigs, cows, and other domestic animals. But with the explosive urban growth of the early 1800s, supply quickly exceeded demand, and streets, alleys, and cesspools were soon overloaded, clogged, and overflowing with waste.

According to one concerned official investigating sanitary conditions in Leeds at the time, “The surface of these streets is considerably elevated by accumulated ashes and filth... stagnant water and channels so offensive that they lie under the doorways of the uncomplaining poor, and privies so laden with excrementitious matter as to be unusable...” In many cases, overflowing cesspools rose up through the floorboards of a house or drained into nearby water cisterns and private wells for drinking water.

The public water supply was no better. One report found that the River Aire, a source of drinking water for many inhabitants of Leeds, was “charged with the contents of about 200 water closets [toilets], a great number of common drains, dead leeches and poultices from the infirmary, soap, blue and black dye, pig manure, old urine wash, and all sorts of decomposed animal and vegetable substances...”

Such was the setting in May, 1832, when cholera arrived in Leeds and claimed its first victim—a two-year-old child of a weaver who lived in “a small and dirty cul de sac inhabited by poor families.” In six months—with no one understanding what it was or how it killed—cholera would take another 700 lives. Before subsiding later that year, more than 60,000 people in all of England would be dead of the disease. Although physicians and officials initiated frantic efforts to uncover and stop the culprit, over the next 35 years there would be three more epidemics that would claim more than 100,000 lives.

Nevertheless, well before the second epidemic, a prickly lawyer had begun to lay the groundwork for what would ultimately help end the ravaging epidemics and loss of human life. And although Edwin Chadwick was abrasive, brow-beating, and widely disliked, he, like John Snow, would play a key role in the greatest medical breakthrough in history.

* * *

When asked what the greatest medical advance is in the past two centuries, most people furrow their brows a moment and then give perfectly reasonable answers such as antibiotics, vaccines, x-rays, or even aspirin. When this question was recently posed to readers of the British Medical Journal, they came up with similar responses, along with some surprises, such as oral rehydration therapy, the iron bedstead, and salutogenesis. But when the BMJ tallied results from more than 11,000 readers across the globe, one medical advance beat out all others: Sanitation.

Sanitation broadly refers to the creation of a healthy environment through the provision of clean water, safe waste disposal, and other hygienic practices. Though it may not sound as technologically impressive as a polio vaccine or CAT scan, sanitation is arguably the most important of all medical breakthroughs because, once established, many diseases can be prevented in the first place. The principles of sanitation may seem obvious—most of us learn the basics of toilet training as toddlers—but at the dawn of the Industrial Age, the inability to provide sanitation on a large scale posed a genuine threat to the future of modern cities. It would take decades to even conceive of a reasonable solution, and decades more before the solution could be implemented.

While many individuals contributed to the development of sanitation, two people stand apart for their milestone insights and achievements. Although John Snow and Edwin Chadwick shared one thing in common—continuing battles with skeptical contemporaries—they could not have been more different in their personalities. Snow was described as “kindly in nature” and “always open and of sweet companionship,” while the barrister Edwin Chadwick was a man “no one ever accused of having a heart” and possibly “the most hated man in England.”

Nevertheless, from the 1830s to the 1850s, both were driven to solve the same mystery that had originated half-way across the world: What was killing tens of thousands of people and how could it be stopped?

* * *

It often begins with a sudden awakening at night—a roiling, squeezing urgency in the abdomen that sends one scrambling for the nearest toilet. Once there, relief is quickly replaced by the sickening depth of the purge. Though initially painless, the watery diarrhea is massive and alarming, the body discharging itself like fire hose. In a single day, more than five gallons of water may be lost. So intense is the purging that the intestinal lining is literally stripped and flushed away, the bits of tissue giving the diarrhea a characteristic “rice water” appearance. Before long, the first signs of dehydration—the final deadly blow—appear: muscle cramps, wrinkled and purplish blue skin, sunken eyes and pinched face, the voice reduced to a hoarse whisper. The disease strikes so suddenly that collapse and death can occur in hours. But even after death, the watery discharge itself continues to teem with life, seeking to infect others, wherever it may go...

Milestone #1 The first epidemic: a lesson from the depths of a coal mine

In the winter of 1831–1832, when John Snow was just 18 years old and barely underway with his medical apprenticeship, his surgeon-teacher sent him on unenviable mission: He was to go into the heart of a cholera epidemic, the Killingworth coal mine near Newcastle, to help the many miners who were suffering from a deadly disease for which there was no cure or treatment. Snow followed his instructions and, in the end, his tireless efforts to assist the miners were deemed a success. But perhaps more important, the experience left an indelible impression that would lead to his first milestone insight: If miasmas were truly the cause of cholera as everyone believed, how could the miners have contracted the disease while working in deep underground pits, where there were no sewers, swamps, or other miasmatic vapors to be inhaled?

As Snow later remarked in building his case that cholera was caused not by miasma but by poor sanitation:

“The pits are without any privies, and the excrement of the workmen lies about almost everywhere so that the hands are liable to be soiled with it. The pitmen remain underground eight or nine hours at a time, and invariably take food down with them into the pits, which they eat with unwashed hands... Therefore, as soon as a case of cholera occurs among any of the pitmen, the disease has unusual facilities of spreading...”

After the first epidemic ended, Snow made his way to London, where he completed his medical training and pursued an entirely different medical field—the use of ether as an anesthetic during surgery. While he would eventually receive worldwide acclaim for this work—the subject of another chapter in this book—he never abandoned his interest in cholera. In fact, his research into the properties of inhaled gases only increased his doubts that cholera was caused by miasma. But with the first epidemic over, he lacked sufficient evidence to elaborate further on his theory that cholera was transmitted by the watery intestinal discharges of sick people.

Snow did not have to wait long for a new opportunity to gather more evidence. But would it be enough?

Milestone #2 Casting aside miasma to envision a new kind of killer

When the second outbreak of cholera hit London in 1848, 35-year-old Snow was mature enough to recognize the intersection of fate and opportunity when he saw it. As people began to die from an epidemic that would eventually claim another 55,000 lives, Snow began tracking the killer with a passion that bordered on obsession. Starting from square one, he learned that the first victim of this outbreak was a merchant seaman who had arrived in London from Hamburg by ship on September 22, 1848. The man had rented a room and died a short time later of cholera. Questioning the victim’s physician, Snow learned that after the seaman died, a second person had the same room and died of cholera eight days later. Perhaps, Snow reasoned, something left behind by the first victim—for example, unwashed bed linen—had infected the second.

Snow continued his investigations and continued to turn up evidence that—contrary to the view of other medical authorities of the time—the disease was both contagious and could be transmitted by contaminated water. For example, he learned that in one section of London where two rows of houses faced each other, many of the residents in one row of houses developed cholera, while only one person in the other row became ill. Snow investigated and discovered that in the houses where people had been infected, “slops of dirty water, poured down by the inhabitants into a channel in front of the houses, got into the well from which they obtained their water...”

In another line of evidence, Snow noted that in every person stricken with cholera, just as he’d seen with the coal miners years before, the first symptoms were gastrointestinal—diarrhea, vomiting, and stomach pain. To Snow, the implication was clear: Whatever the “toxin” was, it must enter the body by swallowing contaminated food or water. If it were inhaled from some form of miasma, he reasoned, it would first enter the lungs and bloodstream, causing such symptoms as fever, chills, and headache.

Eventually, these and other observations enabled Snow to envision an invisible killer—an uncanny insight given that it would be decades before scientists would discover bacteria and viruses as causes of disease. But casting aside miasma theory, Snow concluded that cholera was caused by some kind of living agent that had “the property of reproducing its own kind” and “some sort of structure, mostly likely that of a cell.” He further proposed that it “becomes multiplied and increased in quantity on the interior surface of the alimentary canal.” Finally, he accounted for the incubation time before the first symptoms appeared by suggesting that “The period which intervenes between the time when [it] enters the system and the commencement of the illness which follows is a period of reproduction....”

In this way, Snow pushed the concept of germ theory further than anyone had prior to that time.

In 1849, hoping that his findings might lead to changes in policy and behavior that could end the outbreak, Snow published his views in a pamphlet, “On the Mode of Communication of Cholera.” Yet despite his insights, Snow’s colleagues were not impressed. While some grudgingly admitted that cholera might be transmitted from person to person “under favorable conditions,” most contended that cholera was not contagious and, though related to poor sanitation, could not be transmitted by water.

Despite this setback, Snow did not give up. When the second epidemic subsided in 1849, he continued investigating other lines of evidence to support his theory. So far, he’d seen that in isolated outbreaks, such as in the coal mines and the Barnes family incident, cholera could be spread by poor hygiene and person-to-person contact. And he’d seen that in larger community outbreaks, cholera could be tracked to local wells that had been polluted by nearby cesspools. But to explain the massive scale of outbreaks that killed thousands of people, his aimed his sights on a new target: the public water supply.

It did not escape Snow’s attention that at the time, the Thames River, a tidal river that flows through the center of London, served two contradictory public needs: sewage disposal and water supply. In fact, one of the city’s sewage outflows emptied untreated into an area of the river where even sewage that had been carried away could be washed back during high tide. Investigating municipal records, Snow found that two major water suppliers—the Southwark and Vauxhall Company, and Lambeth Waterworks—pumped water from the Thames River to residents without filtration or treatment. However, in 1849, only one of these companies—Lambeth—took its water from an area of the river almost directly opposite the sewage outfall. Snow began collecting data, and his suspicions were soon confirmed: Communities who received their water from Lambeth had higher rates of cholera than those whose water came from Southwark and Vauxhall.

Snow was now on the brink of his two final milestones—just as London was about to suffer its third major outbreak of cholera.

Milestone #3 The invention of epidemiology and the disabling of a deadly pump

Although the third cholera epidemic began in 1853, it was not until August 31, 1854, that it would explode into the now-famous “Broad Street pump incident.” In that incident, in less than two weeks, some 500 people who lived within 250 yards of the Golden Square area of Broad Street died of cholera. It was a mortality rate that, according to Snow, “equals any that was ever caused in this country, even by the plague.”

But even before Snow would play his famed role in the Broad Street outbreak, he was investigating the Southwark and Vauxhall and Lambeth water companies for their possible roles in this epidemic. Since the 1849 epidemic, Lambeth had moved to an upstream location above the sewer outlets and was now providing cleaner water than Southwark and Vauxhall. Snow was intrigued when he discovered that the two companies—who supplied water to at least 300,000 people—piped water down the same streets, but to different houses. This enabled him to conduct an investigation “on the grandest scale.” By determining which houses received which water supply, he could compare the numbers of people stricken with cholera against where they lived and whose water supply they received. Snow’s epidemiological research did not let him down: During the first four weeks of the summer outbreak, the rates of cholera were 14 times higher among those received Southwark and Vauxhall water compared to those who received the cleaner water from Lambeth. Once again, the evidence supported his theory that cholera could be transmitted by polluted water.

Snow was just beginning to sharpen his epidemiological tools. When the Broad Street epidemic broke out a few weeks later, on August 31, he immediately began new investigations. Over the course of several weeks, he visited numerous homes in the afflicted neighborhood and conducted interviews with sick people and their families. In this case, the water supply in question was from local wells, rather than the polluted Thames. Before long, Snow had identified all of the water pumps in the area, calculated their distances to the houses of the people who contracted cholera, and made a startling discovery: In one section, 73 of the 83 cholera deaths occurred in homes that were closer to a pump located on Broad Street than to any other pump, and 61 of the 73 victims had drunk water from that one pump.

This was strong evidence, and when Snow presented it to local officials, they agreed to shut down the Broad Street pump by removing its handle. But though this apparently ended the epidemic, it was not quite the victory Snow hoped for or is sometimes presented in popular accounts. For local officials, the idea that cholera had been transmitted by polluted water was still impossible to accept. Other factors could be found to explain why the outbreak ended and why water from the Broad Street pump might not have been the cause. For example, the outbreak may have ended not because the pump was disabled, but because the epidemic had already peaked, or because so many people fled the area when the outbreak began, and no one was left to be infected. But perhaps the most damning evidence against Snow’s theory came when subsequent investigations found that the Broad Street pump water was notpolluted.

Nevertheless, Snow remained convinced that the local outbreak was caused by contaminated water from the Broad Street pump. And in March 1855, in an extraordinary epilogue to the story, he would be vindicated by an unlikely hero...

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Reverend Henry Whitehead was a deacon at St. Luke’s Church who had no medical training and did not even believe Snow’s theory that cholera could be transmitted by water. Nevertheless, impressed by Snow’s investigations of the 1849 epidemic and compelled by the mystery of why the Broad Street outbreak had ended so quickly, Whitehead began his own investigations. Reviewing reports of the cholera deaths during the first week of the outbreak, Whitehead made a dramatic discovery: A five-month-old infant living at 40 Broad Street had died on Sept. 2, but her symptoms had begun several days earlier, before Aug. 31, when the massive outbreak began. Whitehead immediately recognized the significance of two key facts. The infant had to have been the first victim of the Broad Street outbreak, and she lived in a house at 40 Broad Street—which was directly in front of the Broad Street pump.

The rest of the story came together quickly. Whitehead interviewed the infant’s mother, who recalled that at the time of her infant’s illness, just prior to the full-scale outbreak, she had cleaned her child’s diarrhea-soaked diapers in a pail of water. She then emptied the dirty water into a cesspool opening in front of the house. When inspectors were called in to examine the cesspool, they not only found that it was located less than three feet from the Broad Street well, but that the cesspool had been leaking steadily into the pump’s well. With this discovery, Whitehead’s original question was answered, and the mystery of the outbreak was solved: The first days of the outbreak coincided with the time when the diaper water was being emptied into the leaking cesspool; the epidemic subsided rapidly after the infant died and the diaper water was no longer being poured into the cesspool.

Yet although officials initially agreed with Whitehead and Snow that the new findings linked the contaminated pump water with the outbreak, they later rejected the evidence, convinced that some unknown miasmatic source must have been the cause.

* * *

When John Snow died of a stroke a few years later at the age of 45, the medical community still rejected his theory that cholera was caused by contaminated water. Yet it is satisfying to know that when the fourth and final outbreak of cholera hit London in 1866—ultimately claiming another 14,000 lives—it was Henry Whitehead who tracked the outbreak to a water company that had been supplying its customers with unfiltered water from a polluted river. And until he died in 1870, Whitehead kept a picture of Snow on his desk.

Physicians would continue to reject Snow’s theory for several more decades. Finally, around the end of the nineteenth century, as bacterial theory began to displace the misconception of miasma, Snow began to be recognized for the achievements he made decades before the world was ready to believe him. Today, he is revered not only as the man who solved the mystery of cholera, but the father of modern epidemiology.

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The true identity of cholera was first discovered in the very year that officials were rejecting John Snow’s evidence for the cause of the Broad Street pump outbreak. In a separate outbreak in Florence, Italy, scientist Filippo Pacini had been studying intestinal tissue from cholera victims under a microscope and described what he saw in a paper published in 1854: tiny, rod-shaped organisms whose slight bend gave them a “comma-shape” and whose busy movement he described as “vibrio.” Convinced the tiny organisms were responsible for causing cholera, Pacini published several more papers on the topic. Although John Snow never learned of Pacini’s discovery, the two shared one thing in common: No one believed Pacini, either. His findings were ignored for the next 30 years. Even when Robert Koch, the founder of the science of bacteriology, “rediscovered” the bacteria in 1884, the best German scientists at the time rejected his conclusions in favor of a miasmatic explanation. Pacini eventually did receive credit—only a century late—when in 1965 the bacterium was officially named Vibrio Cholerae Pacini 1854.

Milestone #4 A new “Poor Law” raises hackles—and awareness

In the early 1830s, as John Snow was being duly praised for his first career milestone of helping cholera-stricken coal miners, a young lawyer named Edwin Chadwick also achieved his first career milestone—and was being duly despised. It’s not surprising that Chadwick was hated for his role in creating the 1834 Poor Law Amendment Act: A key principle of the law was to make public relief so miserable to poor people that they would avoid it altogether. And from there, Chadwick’s reputation only grew worse. Apart from being called an “oppressor of the poor” and possibly “the most hated man in England,” he later became famous for battling officials, physicians, and engineers, for his overbearing and insensitive personality, and for being a man who did not so much converse with others as browbeat them into submission.

It’s a good thing he turned out to be right.

In the end, Chadwick’s bull-headed efforts would ultimately not only help improve the living conditions of the poor, but lead to the greatest medical breakthrough in history. The significance of Chadwick’s first milestone was not the Poor Law itself, but what he achieved in his research to write the law. In fact, Chadwick did not oppose the poor so much as the deplorable conditions in which they lived. Like most people of the time, Chadwick realized that the growing unsanitary conditions in England’s cities was somehow responsible for disease and the recent outbreak of cholera. Also, like most others, he was completely wrong about miasma causing cholera, to the extreme of publicly stating at one point, “All smell is disease.”

Yet though technically wrong about the cause of cholera, Chadwick was right in principle, and in researching the Poor Law, he gathered an abundance of evidence linking unsanitary conditions with the living conditions of the poor. In fact, his documentation was so comprehensive—so much more thorough than anything done by his predecessors—that in designing the law he transformed policy analysis and drew widespread attention from his peers. Thus, even as he drew severe criticism for the Poor Law, Chadwick’s research marked a key milestone that would soon lead to a reversal of fortune.

That reversal came in 1839. With sanitary conditions worsening, and in the wake of a two-year influenza epidemic, government officials decided it was time to take action. Impressed by Chadwick’s thoroughness in writing the Poor Law, they asked him to report on the sanitary conditions and diseases in England and Wales and to provide recommendations for policy and technology solutions.

Chadwick accepted the new assignment, to the delight of the co-workers he was leaving behind: They’d found him impossible to work with.

Milestone #5 A grand report creates a wealth of ideas and a will to act

In 1842, after several years of research and writing, Chadwick released his report, On the Sanitary Condition of the Labouring Population of Great Britain. The fact that it was an immediate best-seller—selling more copies than any previous government publication—indicates how concerned people were about the sanitation problem. Compiled with the help of physicians and officials who described the conditions in their own towns and cities, the report presented an accurate image of the disease-causing filth plaguing many cities of England. At one point, referring to an epidemiological map of Leeds during the 1831–32 epidemic, Chadwick noted the clear link between unsanitary conditions and cholera. “In the badly cleansed and badly drained wards,” he wrote, “[the cholera rate] is nearly double that which prevails in the better conditioned districts...”

But more than a roll-call of England’s sanitary failures, the 1842 report was a milestone in several ways. First, it emphasized that the cause of poverty and disease, rather than a curse of God’s will as many believed at the time, was due to environmental factors. Second, the report represented a culmination of a new public health movement that blamed poor sanitation on the industrial slums. Finally, and perhaps most impressive, it described Chadwick’s groundbreaking ideas for an engineering and governmental solution—in short, the invention of modern sanitation.

A major part of Chadwick’s grand vision was his proposal for an “arterial-venous” system. The first time anyone had viewed water and sewage as an interlocking problem, this “hydraulic” or “water carriage” system would pipe water into homes for the purpose of rinsing waste materials away through public sewers. It was a daring idea that proposed nothing less than a rebuilding of the urban infrastructure. It would require a city’s terrain to be designed with proper street paving, sloping, and gutters so that the “self-cleaning” sewer pipes would remove sewage before decomposition would cause disease. Chadwick even proposed unique sewage pipes that were egg-shape in cross-section—rather than the usual circular design—to increase flow velocity and prevent solid deposits. Finally, rather than simply dumping sewage into the nearest river as many piecemeal systems of the time did, Chadwick wanted the waste to be directed to farms, where it would be recycled for agricultural use. In its sum, Chadwick’s integrative sewer design was a first-of-its-kind; nothing like it existed in Europe or the United States.

Unfortunately, it was also far easier to describe than build. For although Chadwick also proposed new legal and administrative structures by which such systems could be financed and built, there was no existing model for how such a complex, citywide system could be implemented. At the same time, there were countless opportunities for various groups to argue over who should plan, build, finance, and maintain them. Nevertheless, after several years of legislative wrangling and haranguing by Chadwick and others, a solution finally emerged in 1848. Sort of.

Milestone #6 The long, slow birth of a public health revolution

The passage of the 1848 Public Health Act was considered to be the crowning point of Chadwick’s work and a milestone in English public health. With this law, for the first time in history, the British government assumed responsibility for protecting the health of its citizens, for implementing the legal systems needed to guarantee sanitation.

But in reality, the law had numerous shortcomings that would not be solved for years. For example, despite passage of the Act, many guidelines were left to the discretion of local government. In some cases, Chadwick or his followers found themselves embarrassing, threatening, or harassing local governments into cleaning up their own filth. At that same time, those who were bold enough to attempt to build Chadwick’s system often ran into technical difficulties that could not be resolved without compromising the grand plan. Thus, despite years of trying to make his sanitary system work—from abrasive arguments with engineers over technical details to accusations of the moral failings of opponents who stood in his way—Chadwick’s grand vision ultimately turned out to be too ambitious.

Yet despite these setbacks, by the mid-1800s, Chadwick’s work and vision began to manifest in positive ways. Though not as ambitious as the integrative system he had envisioned, urban sanitation systems that reflected his engineering and governmental ideas began to appear. And the early results were promising. According to one study of 12 large towns in Great Britain, death rates had dropped from 26 per 1,000 before sewage systems, to 17 per 1,000 after the systems were adopted.

What’s more, by the 1860s and 1870s, the sanitary systems developed by Chadwick and other English engineers were having an international influence. In the 1840s, the first efforts to build sewers in large cities like New York and Boston had led to piecemeal, non-integrated systems with key design flaws. But by the time of the Civil War and into the 1870s, many U.S. cities had begun to implement “planned” systems based on what became known as “English sanitary reform.” As one Massachusetts engineer of the time noted, “Our countrymen have seized upon the water-carriage system with great unanimity.”

Back in England, the work of Chadwick and his followers finally culminated with the 1875 Public Health Act, the most comprehensive sanitary law in England to that date. Looking back on it now, the Public Health Act and proliferation of urban sanitation systems in the late 1800s could be traced back to three criteria that Chadwick had identified and championed as essential to modern sanitation: 1) recognition of the link between environment, sanitation, and health; 2) the need for a centralized administration to deliver and maintain sanitation services; and 3) a willingness to invest in the engineering and infrastructure needed to make such services possible.

* * *

One of the lessons of Chadwick’s lifelong work is that as long as you’re right, it’s okay if it’s for the wrong reasons. Throughout his life, Chadwick remained as adamant and misguided as his contemporaries in insisting that cholera was caused by miasma. Like many others, he was unimpressed by Koch’s “rediscovery” of the Vibrio cholerae (V. cholerae) bacterium in 1883, and at one point he even argued that it was more important to remove foul smells from houses than to provide clean water. But even if technically wrong, you have to give him credit: He knew a bad thing when he saw—or rather—smelled it.

Today, Chadwick’s achievements are viewed as a turning point in the history of modern sanitation. Set against the backdrop of widespread unsanitary conditions of the Industrial Revolution and 30 years of cholera epidemics, Chadwick raised awareness—and the bar—for the importance of sanitation to the health of a city and its inhabitants.

* * *

John Snow and Edwin Chadwick were men of great similarities and contrasts. Different in temperament and occupation, they were driven by a common enemy. Contrary in their views regarding the specific cause of cholera, both recognized the broader underlying problem to be a failure of human sanitation. In the end, Snow’s epidemiological work and insights revealed to the world that contaminated water can spread serious gastrointestinal disease—what we now call the “fecal-oral route.” And Chadwick’s documentation linking poor sanitation and disease, along with his engineering and legislative innovations, helped make modern sanitation possible on an urban scale.

The work of Snow and Chadwick did not exactly overlap, but converged at a time when hundreds of thousands of people were vulnerable and terrified by an epidemic that could strike suddenly and wipe out entire families in days or even hours. In separate but additive ways, they helped “concentrate” the minds of an old world on the brink of a new age. Raising awareness, they helped nudge a reluctant humanity into a new phase of urban civilization, where modern sanitation would be essential to survival.

Cholera and the failure of sanitation: alive and well in the twenty-first century

In the twenty-first century, more than 150 years after it was first identified, Vcholerae remains alive, well, and deadly throughout much of the world in epidemic or endemic form. The good news is that today, with rapid oral rehydration and antibiotics, nearly all cholera deaths can be avoided. The bad news is that in many areas where cholera is a problem—including recent epidemics in Iraq, Rwanda, and Central and South America—treatment is not always available, and death rates remain as high as 50%.

While new vaccines offer better protection and fewer side effects than older versions, they remain limited by the difficulty of distributing them to the populations at risk—typically in developing or war-ravaged countries—and the need for frequent booster doses. What’s more, even the best vaccines may be ineffective against the extraordinary numbers of cholera bacteria—as many as 100 million—found in just one gram of watery diarrhea. Scientists point out that cholera will probably never be eliminated. Given that the natural habitat of V. cholerae coincides with the vast watery ecology of our planet, new epidemic strains are likely to always develop, evolve, and spread. Rather, scientists suggest that we learn to “get along” with V. cholerae by focusing on two basic goals: develop better ways to fight the causative organism and create better sanitation systems to prevent their spread.

Snow and Chadwick couldn’t have put it better.

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Perhaps what is most surprising about V. cholerae is that it is not one species, but a large family of ocean-loving bacteria—a family that is almost universally harmless. Of the 200 known strains of V. cholerae, only two (called O1 and O139) possess the unique combination of genes needed to thrive in the intestines of human beings and produce their deadly toxin. One group of genes produces TCP, the substance that enables V. cholerae to colonize the intestinal lining; the other gene cluster, called CTX-ø, produces the lethal toxin that enters intestinal cells and convinces them to manically pump out every last drop of water until the human host dies. Curiously, while all 200 strains of V. cholerae live in brackish estuaries, O1 and O139 are the only two strains that contain the deadly cholera genes and are found in water polluted by humans.

This raises an interesting question: Who contaminated whom?