The Ghost Map

John Snow, along with Henry Whitehead, is the closest thing to a protagonist in the book. A brilliant, creative thinker, Snow grew up in a working-class family, and later worked his way up to become one of London’s most prominent anesthesiologists. While most doctors in Snow’s position would have become complacent, Snow continued to research new topics in medicine; in the late 1840s, he became interested in cholera. During the 1854 cholera epidemic, Snow saw an opportunity to test his theory that cholera was a contagious, waterborne disease—a perfectly uncontroversial theory by 21st century standards, but one which was widely ridiculed at the time. Snow interviewed dozens of families and tested water samples from numerous households, ultimately concluding that the Broad Street water pump was responsible for spreading cholera through the neighborhood of Soho. Although Snow’s contributions to anesthesiology and the germ theory of disease would each be enough to assure him a place in medical history, arguably his greatest contribution was his pioneering work in medical cartography. Snow assembled elegant, insightful maps that documented the relationship between foot traffic and the spread of disease. His work remains important in the 21st century, when preventing the spread of disease is one of the central concerns of urban planners. Snow, like Whitehead, was a brilliant, highly dedicated man, who wasn’t afraid to challenge the accepted orthodoxy of the medical community. Although he died in his forties, Snow’s theories of cholera eventually became as widely accepted as they’d once been controversial.

John Snow Quotes in The Ghost Map

The The Ghost Map quotes below are all either spoken by John Snow or refer to John Snow. For each quote, you can also see the other characters and themes related to it (each theme is indicated by its own dot and icon, like this one:
Illness, Death, and the Unknown Theme Icon
). Note: all page numbers and citation info for the quotes below refer to the Riverhead Books edition of The Ghost Map published in 2007.
Chapter 3 Quotes

Snow was a truly consilient thinker […] Snow’s work was constantly building bridges between different disciplines, some of which barely existed as functional sciences in his day, using data on one scale of investigation to make predictions about behavior on other scales.

Related Characters: John Snow
Page Number: 67
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Snow also recognized the weakness of the contagionist argument. […] Clearly, the cholera was not communicated through sheer proximity. In fact, the most puzzling element of the disease was that it seemed capable of traveling across city blocks, skipping entire houses in the process.

Related Characters: John Snow
Page Number: 71
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Chapter 6 Quotes

In explaining Snow's battle against the miasma theory and the medical establishment, it's not sufficient to point to his brilliance or his tenacity alone, though no doubt those characteristics played a crucial role. If the dominance of the miasma model was itself shaped by multiple intersecting forces, so, too, was Snow’s ability to see it for the illusion that it was.

Related Characters: John Snow
Page Number: 144
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Chapter 7 Quotes

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.

Related Characters: John Snow
Related Symbols: The Pump Handle
Page Number: 160
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Chapter 8 Quotes

As for influence, it's pretty to think of John Snow unveiling the map before the Epidemiological Society to amazed and thunderous applause, and to glowing reviews in The Lancet the next week. But that's not how it happened. Its persuasiveness seems obvious to us now, living as we do outside the constraints of the miasma paradigm. But when it first began circulating in late 1854 and early 1855, its impact was far from dramatic. Snow himself seems to have thought that his South London Water Works study would ultimately be the centerpiece of his argument, the Broad Street map merely a piece of supporting evidence, a sideshow.

Related Characters: John Snow
Page Number: 198
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John Snow Character Timeline in The Ghost Map

The timeline below shows where the character John Snow appears in The Ghost Map. The colored dots and icons indicate which themes are associated with that appearance.
Chapter 3: The Investigator
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On Sunday, a forty-two year-old Soho regular named John Snow was walking through the streets. Snow’s father was a Yorkshire laborer. When the young Snow... (full context)
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Most doctors in Snow’s position would have settled into a comfortable, upper-middle-class life. However, Snow remained ambitious—in particular, he... (full context)
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Snow devoted himself to determining correct ether dosages. By January 1847, he’d published a table of... (full context)
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By the end of the 1840s, John Snow had become fascinated with cholera. There was a cholera outbreak in 1848, and Snow wanted... (full context)
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In the course of his research, Snow found reports of a Hamburg steamship, one of whose crew members checked into a lodging... (full context)
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By 1849, Snow was ready to present his research to the public: cholera, he argued, was caused by... (full context)
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In 1854, with the cholera outbreak, Snow began to study Soho’s water supply. He was surprised to find that the water looked... (full context)
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The very same evening, John Snow was looking over the mortality numbers for the 1854 outbreak compiled by William Farr. Snow... (full context)
Chapter 4: That Is To Say, Jo Has Not Yet Died
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...specific places and odors that fostered the spread of disease—was still popular, in spite of Snow’s research. Clergymen like Whitehead, meanwhile, clung to their religious faith in times of cholera epidemics.... (full context)
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...therefore they had a hard time conceiving of the ways that diseases spread. Cholera, John Snow quickly found, couldn’t be studied in isolation: it had to be seen from a “bird’s... (full context)
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On Monday, John Snow was busy trying to find a “wider perspective” for the study of cholera. Around the... (full context)
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...systems for the whole city. When researching the spread of cholera in the late 1840s, Snow discovered that the people dying of cholera lived in a district of London whose piping... (full context)
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Leading up to the cholera outbreak of 1854, John Snow had been visiting the Soho slums and inquiring about cholera victims’ water supplies. He visited... (full context)
Chapter 5: All Smell is Disease
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...miasma theory—and its persistent failure to better Londoners’ lives—made it easier for people like John Snow to see the theory’s weaknesses, so that miasma theory ultimately collapsed on itself. (full context)
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John Snow spent Tuesday, September 5 walking through Soho, searching for cholera patterns. He visited the Registrar-General’s... (full context)
Chapter 6: Building the Case
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...epidemic of 1854, but their deaths became an important piece of the puzzle for John Snow. (full context)
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After studying Farr’s latest figures, Snow came to realize that, while most of the cholera victims of 1854 had gotten their... (full context)
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In following interviews, John Snow was able to determine that some of the other cholera victims living on Cross Street... (full context)
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After more research, Snow discovered that not one of the Lion Brewery’s employees had died of cholera—quite possibly because... (full context)
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John Snow was a brilliant man, crusading against a medical establishment that believed in a false theory.... (full context)
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It’s worth remembering that Snow lived less than six blocks from the outbreak of the cholera epidemic—suggesting that his interest... (full context)
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By the end of the day, John Snow had built a strong case against the Broad Street pump: the vast majority of deaths... (full context)
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...still killing people. A dozen people died in Soho that day—ten times the normal rate. Snow prepared to finalize and publish his research, but before he did so, there was “a... (full context)
Chapter 7: The Pump Handle
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...had a meeting to discuss how the neighborhood would respond to the cholera outbreak. John Snow spoke at the meeting, insisting that the community needed to remove the pump as soon... (full context)
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...he vowed to disprove the waterborne theory of cholera—and in the end, his opposition to Snow’s theory proved invaluable, since it strengthened Snow’s theory. Whitehead began by interviewing elderly people who’d... (full context)
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...encyclopedic knowledge of the outbreak. On the committee, Whitehead offered a vigorous attack on John Snow’s theory that the Broad Street well was to blame for the outbreak, pointing out that... (full context)
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As Whitehead conducted further research, he began to come around to John Snow’s theory. Some of the families who Whitehead interviewed later remembered that their deceased loved ones... (full context)
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Whitehead was coming around to John Snow’s theory, but he still had some objections. First, he wondered why the outbreak hadn’t occurred... (full context)
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As the data about the cholera outbreak continued to pile up, Whitehead began to believe Snow’s theory. He began searching for an “index case”—i.e., the earliest cholera victim of 1854. While... (full context)
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The St. James Vestry Committee issued a report hypothesizing that, just as John Snow had argued, the cholera outbreak was caused by contamination of the Broad Street well. The... (full context)
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...began emptying his diarrhea into the cesspool, infecting the Broad Street pump once more. Had Snow not convinced the authorities to remove the pump handle, the outbreak probably would have continued. (full context)
Chapter 8: Conclusion
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John Snow then began making his own map of the cholera epidemic. Snow’s map showed each victim’s... (full context)
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John Snow’s map was a milestone in the history of epidemiology, reflecting both Snow’s training as a... (full context)
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Even if John Snow’s map failed to convince the medical establishment, it convinced one very important person of the... (full context)
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...in London’s history, but it had a silver lining: it was a triumph of science. Snow was a master at drawing bold conclusions from the data. Furthermore, the aftermath of the... (full context)
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...in 1858 was perfectly normal. But just as miasma theory was beginning to collapse, John Snow suffered a stroke, and died days later—he was only forty-five. (full context)
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In the late 1850s, partly because of Snow’s groundbreaking research, the London municipal government decided to build a new sewer system. London’s sewer... (full context)
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...uncover a pattern of company negligence that almost certainly resulted in thousands of deaths. Although Snow was dead by this point, Farr and Whitehead regularly credited him for his waterborne theory... (full context)
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...such as Edwin Chadwick, continued to support miasma theory, but most public health institutions embraced Snow and Koch’s research. In London, the new sewer system resulted in cleaner drinking water and... (full context)
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...in London in the 19th century. Using the cartographical and epidemiological methods pioneered by John Snow and Henry Whitehead, contemporary thinkers have found ways of reorganizing cities more efficiently. The Internet... (full context)
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The 311 calling system reflects a paradigm for urban planning that emerged thanks to John Snow and Henry Whitehead’s cholera research. The first aspect of this paradigm is the importance of... (full context)
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...a minister in various northern English cities; he died in 1896. A portrait of John Snow hung in his office—to remind him that “in any profession the highest order of work... (full context)
Epilogue: Broad Street Revisited
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...a few decades, that figure will shoot up to eighty percent. At the time when Snow and Whitehead were alive, a mere ten percent of the population was urban. Human thought... (full context)
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To no small extent, Snow and Whitehead made the contemporary urban world possible. Thinkers no longer doubt that it’s possible... (full context)
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...the most powerful defensive tools humans have is mapping, of the kind pioneered by John Snow. It’s not enough to research new vaccines in response to outbreaks of disease—urban planners must... (full context)
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...millions on nuclear weapons. But humanity would do well to remember Henry Whitehead and John Snow. Instead of despairing in the face of what seemed an unsolvable problem, Whitehead and Snow... (full context)