Take this 5-question quiz to see how much you know about John Snow’s historic investigation of cholera in 1854.

1. John Snow Cholera Outbreak
Fact or fiction?
Take this quiz to see how much you know about John Snow’s
historic investigation of cholera in 1854.

2. 1. At the time of the devastating cholera outbreaks in 19th century
London, it was a new disease about which little was known.
True?
False?

3. 1. At the time of the devastating cholera outbreaks in 19th century
London, it was a new disease about which little was known.
False
Although its etiology was unknown, over 700 books and
pamphlets dealing with cholera were published in London during
the time of the third pandemic (1839-1856). Most adhered to
the prevailing thought, known as the miasma theory, that cholera
was the result of a noxious form of bad air.

4. While true that the microscopic organism Vibrio cholerae would not be
identified until 1883, British doctors had been treating cholera for
hundreds of years. However, it had been seasonal and cases were
generally mild and came to be known as cholera nostra (“our cholera”),
after the much more virulent “Indian” cholera arrived in the 1830s like a
penance for Victorian imperialism.
Vibrio cholera

5. 2. John Snow was a London physician who went door-to-door collecting
information about deaths from cholera, which led him to identify water as the
likely cause of the outbreak.
True?
False?

6. 2. John Snow was a London physician who went door-to-door collecting
information about deaths from cholera, which led him to identify water as the
likely cause of the outbreak.
False
Snow’s investigation was guided by his already-developed theory that cholera is a
localized disease of the gut and the likely route of transmission in this situation was
drinking water.

7. Snow was focused on the wells from the start, and was told by a
community resident that the Broad Street pump had a bad odor
during the height of the outbreak. His data – addresses of 89
fatal cases – came from the General Register Office, and he used
this to make detailed inquiries during the first phase of his
investigation.
1849 Cholera prevention poster

8. 3. Snow noted all the cholera deaths with black horizontal bars on a map of the
area, and was able to use this spot map to prove to the Board of Health that the
Broad Street pump was the cause of the cholera outbreak.
True?
False?

9. 3. Snow noted all the cholera deaths with black horizontal bars on a map of the
area, and was able to use this spot map to prove to the Board of Health that the
Broad Street pump was the cause of the cholera outbreak.
False
Not only did Snow not use a map to discover the source of the outbreak, he also did
not use a map of any kind in his presentations to the Board of Health. The famous
map was created and used several months later as a persuasive illustration for the
London Epidemiological Society.

10. Furthermore, after a decade passed, Dr. Edwin Lankester, who lived in
the area and who had instigated a more thorough investigation into the
outbreak at the time, said of Snow’s waterborne/pump theory: “He was
not believed--not a member of his own profession, not an individual in
the parish believed that Dr. Snow was right. But the pump was closed,
nevertheless, and the plague was stayed.”
Dr. Edwin Lankester

11. 4. Removing the handle of the Broad Street pump did not stop the cholera
epidemic.
True?
False?

12. 4. Removing the handle of the Broad Street pump did not stop the cholera
epidemic.
True
Despite myths and urban legends, the cholera epidemic of 1854 was already
waning when the Board of Health removed the handle of the Broad Street
pump. Snow himself never made any such claims.
Rev. Henry Whitehead, a local cleric who worked with Snow in collecting and
analyzing data, presented a paper to the Epidemiological Society of London in
1867. He used a data table that showed the number of fatal attacks had fallen
from 142 on September 1, 1854, to 14 on September 8, the day the pump
handle was removed.

13. However, Whitehead explained that removing the pump handle served
the important function of preventing a second wave of illness. “…If the
removal of the pump handle had nothing to do with checking the
outbreak which had already run its course,” he said, “it had probably
everything to do with preventing a new outbreak, for the father of the
infant, who slept in the same kitchen, was attacked with cholera on the
very day on which the pump handle was removed.”
1850s Punch magazine cartoon

14. 5. John Snow did not find the index case – the first person with cholera
who initiated the outbreak.
True?
False?

15. 5. John Snow did not find the index case – the first person with cholera who
initiated the outbreak.
True
While working on an unrelated project, Rev. Henry Whitehead inadvertently came
across a report of a 5-month old child who had died on September 2. The cause of
death was listed as exhaustion after having diarrhea for 4 days; the onset of her
symptoms and the length of her illness meant she was sick before anyone else.
Previously it was believed that the epidemic started the night of August 31, when
more than a dozen Soho residents came down with symptoms of cholera. Also, this
child’s family lived in the house closest to the Broad Street pump.

16. Whitehead interviewed the child’s mother and
discovered that she had rinsed the baby’s diapers in
pails of water that she emptied into a cesspool in
the front of the house.
Rev. Henry Whitehead

17. To read more about the historic 1854 cholera epidemic
and the community’s efforts to discover the cause, see
“Map-Making and Myth-Making: John Snow Didn’t
Solve the 1854 Cholera Outbreak with a Map,” at the
Practical Playbook.
Sources:
S. P. W. Chave, B.A. HENRY WHITEHEAD AND CHOLERA IN BROAD STREET. Med Hist. 1958 Apr; 2(2): 92-108, 108-1.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1034367/
“John Snow and Cholera,” a blog post at The Sick City Project by Richard Barnett, PhD.
https://sickcityproject.wordpress.com/2013/03/11/john-snow-and-cholera/