Evidence!: How Dr. John Snow Solved the Mystery of Cholera
by Deborah Hopkinson; illus. by Nik Henderson
Primary, Intermediate    Knopf    40 pp.
8/24    9780593426814    $19.99
Library ed.  9780593426821    $22.99
e-book ed.  9780593426838    $11.99

During the Industrial Revolution, vast numbers of workers moved to cities that housed the new factories. These laborers lived in crowded and often squalid conditions, in areas where the air was thick with noxious odors. One such place was London’s Broad Street, overtaken by a cholera outbreak in 1854. Although the accepted thinking of the time was that such illnesses were transmitted through “bad, smelly air,” Dr. John Snow (1813–1858) does not buy that explanation. He asks questions: why are some individuals sick and others free from disease? How could the air cause diarrhea and vomiting? He investigates by visiting homes of the victims, asking pertinent questions, and creating a map of the affected areas; he then theorizes that cholera must come from something ingested. But what? Here readers see the scientific method at work as Snow determines it is the water, notoriously contaminated by human waste, that causes cholera. Modern epidemiology is born. Henderson’s mixed-media illustrations, in shades of brown, depict the thick, noxious air of Broad Street but lighten as Snow finds evidential proof for his theory. Besides highlighting a historical moment in time, Hopkinson deftly presents a nondidactic object lesson about evaluating information, showing the value of making decisions with facts rather than unverified opinions. The back matter includes information about the Broad Street pump (where cholera victims got their water) and Snow; a glossary of other infectious diseases; and resources for further inquiry.

From the ">November/December 2024 issue of The Horn Book Magazine.