Cholera and the City

At the midpoint of the 19^th Century, many believed that London, a city with almost two and a half million people, was unsustainable. For two decades, cholera epidemics had ravaged London and other major cities in Europe, and prevailing wisdom held that by packing an unprecedented number of people into an area the size of Victorian London the spread of disease was inevitable. And they were right, sort of. In The Ghost Map: The Story of London’s Terrifying Epidemic – and How It Changed Science, Cities, and the Modern World, Steven Johnson tells the story of London’s cholera outbreak of 1854 and how two brilliant men solved the mystery of the deadly disease’s spread.

In the mid-19^th century, a Londoner’s life expectancy was shockingly low: ​“the average ​‘gentleman’ died at forty-five, while the average tradesman died in his mid-twenties.” Even though Victorian London had grown accustomed to death, the 1848-49 cholera outbreak shocked the population when it killed more than 50,000 of the city’s inhabitants. City dwellers lived in constant fear that disease could take their lives with little warning. 

Like all urban areas at the time, London lacked the infrastructure of modern cities. By 1854 a citywide sewer system had begun to appear, in part, to help stem the cholera outbreaks. This newly established sewer system co-existed with the old system of dealing with human excrement – the ​“night soil” men, who hauled the waste that literally filled up the basements of house to farms on the edge of the city. ​“No extended description of London from that period failed to mention the stench of the city,” notes Johnson. 

The new rudimentary sewer system simply dumped household sewage into the Thames River, thereby contaminating the underground rivers that were one of the city’s main water supplies. Ironically, the man in charge of this was London’s sanitation commissioner, Edwin Chadwick. An adherent of the Miasma Theory, which held that cholera was transmitted through a foul stench in the air, Chadwick believed that dumping waste into the river, away from residences, would prevent further outbreaks of the disease. Of course, by contaminating London’s main water supply, he greatly contributed to the spread of cholera. As Johnson points out, a 21^st century biological terrorist couldn’t have devised a more ingenious plot to endanger the city’s population. 

However, it wasn’t just Chadwick. By 1854, the medical community had no better idea of how to prevent cholera than when it first struck London in 1832. The theory of cholera as an airborne illness persisted, and served to reinforce the prejudices of London’s technocrats. According to the dominant theory, those who lived in filth and around foul odors, as the majority of London’s working poor did, were more likely to die of the disease. Few people noticed that the ​“night soil” men, despite their daily dealings with filth, often lived long and healthy lives.

One of those who did was Dr. John Snow. From a humble upbringing, Snow would rise to the pinnacle of 19^th century medicine: Queen Victoria summoned the doctor in 1853 to assist in the administration of chloroform during childbirth, a technique Snow himself had perfected. In addition, Snow was an obsessive physician and medical tinkerer with broad-based intellectual pursuits. Doubting the Miasma theory, Snow set out to prove that cholera had been transmitted via the water supply during the 1848-49 outbreak. But concrete proof of his hypotheses proved elusive: public death records were lacking and clarity regarding which households were supplied water by which of the dozens of private companies made Snow’s analysis too difficult to complete. 

As the summer of 1854 wound down, a cholera outbreak swept through a single neighborhood in London: Soho, Snow’s own backyard. ​“Nearly seven hundred people living within 250 yards of the Broad Street pump had died in a period of less than two weeks,” Johnson writes. Snow roamed the neighborhood at a frenzied pace, testing water and interviewing families about their drinking habits. 

But Snow would not change the course of history alone. It was Rev. Henry Whitehead, originally a doubter of his theory, that helped him piece together his findings and convince Commissioner Chadwick that the disease was water-borne. As a minister and intellectual man-about-town, Whitehead had more knowledge of the families in Soho than any other resident. It was Whitehead’s connections that allowed Snow to find where the outbreak of cholera originated and Snow couldn’t have convinced Chadwick without this crucial information. 

Like Snow, the public health officials who perfunctorily investigated outbreaks in the city lacked on-the-ground knowledge of Soho. Together, Snow and Whitehead were able to convince Chadwick to shut down the Broad Street pump before another outbreak could occur. 

Snow would pass away a few years later, at 45, before it became widely accepted that cholera was transmitted via water, but he had set in motion a transformation of the sewer system that would ultimately prove him correct. No major cholera outbreaks occurred in London after modernization of the sewer systems was completed in 1866.

Johnson’s concluding chapter addresses the problems of today’s emerging cities, which are scarily similar to those of Victorian London. Nairobi and Dhaka have populations approaching 20 million, yet their struggle with lack of clean drinking water and an inadequate public health system go largely unnoticed. The answers to these problems will come in part only with massive investments in these cities’ infrastructures, but both the scale and cultural differences of these cities will require new approaches. 

Johnson hints that our ability to solve the problems of today’s cities might be compromised if we exclude the localized knowledge of figures such as Snow and Whitehead. Indeed, Johnson makes it clear that solving the problems of urban areas requires both a top-down and bottom-up approach. The question he leaves unanswered is whether we are still capable of listening to the ideas of those like Snow and Whitehouse in the era of the Department of Homeland Security.