Evidence! How Dr. John Snow solved the mystery of cholera

Hopkinson returns to the topic of her historical novel The Great Trouble (2013) for a suspenseful case study in scientific investigation and reasoning, describing how a London doctor proved that an 1854 outbreak of cholera was actually caused by water drawn from a single pump rather than, as widely thought, foul air or filthy streets in general. His evidence was circumstantial (the cholera bug being too small to see through his microscope), but along with effectively stemming that outbreak by persuading skeptical officials to remove the pump's handle, he provided a model for epidemiological investigation that went on to revolutionize public health worldwide. Henderson's illustrations of "hot, stinky old London" ("Piles of horse dung line the streets. Sewage and human waste fill cesspools in yards and cellars") are more atmospheric than representational, but images of murky streets and doctors rushing helplessly from patient to patient convey the noxious locale and the desperation of its hapless residents. Back matter adds further information about Snow, the infamous Broad Street pump, and major infectious diseases beyond cholera.

"Welcome to Broad Street, in hot, stinky old London," begins this enthralling 1854-set work focused on epidemiology, smartly pitched for younger audiences as an intriguing medical mystery. With urgent language and expressionistic drawings rendered in graphite and charcoal, and colored digitally, Hopkinson (Cinderella and a Mouse Called Fred) and Henderson (Trucks on Trucks) immerse readers in a close city neighborhood where deadly cholera has broken out: "Piles of horse dung line the streets. Sewage and human waste fill cesspools in yards and cellars." Dr. John Snow (1813--1858) has long investigated cholera--he's been "chasing it for years"and has a theory about the outbreak's cause. That theory, however, flies in the face of prevailing medical and popular wisdom, which holds that cholera is airborne. In spreads that vividly evoke Snow's relentless search across the city, he clearly becomes a "medical detective," mapping cases and interviewing residents. When his work results in the handle being removed from the contaminated Broad Street pump, it's a radiant, reverential moment, as befits "a milestone in science, a shining moment in the long fight against epidemics." Back matter provides further context. Ages 4--8. Author's agent: Steven Malk, Writers House. Illustrator's agent: Chad W. Beckerman, CAT Agency. (Aug.)

Dr. John Snow, "the father of modern epidemiology," discovers the cause of cholera. Behind every great scientist is evidence. When cholera broke out in London in 1854, most people blamed the "bad, smelly air" for the rapid spread of the disease. The English physician Dr. John Snow had a "bold hypothesis." He had noticed that cholera's symptoms included vomiting and diarrhea, so the cause was likely what the victims had ingested rather than something airborne. All he needed was evidence! With expert pacing, Hopkinson sets up Snow's story as a medical mystery and a race against time. The doctor follows clues, gathers information about where the deceased people lived, plots his data on maps, notices clusters of disease, interviews local residents, and discovers the one thing the dead had in common: They had drunk from the same water pump. Henderson's moody, expressionistic art captures Londoners' confusion and concern, while Dr. Snow's urgent pace is marked with literal dashes across city maps. Hopkinson nimbly acknowledges when she's using conjecture--"We can guess the hard questions he must ask"--and makes clear when she's presenting evidence: "This fact is helpful." At the story's climax, Dr. Snow presents his findings at a neighborhood meeting, and in a final, incandescent spread, the water pump's handle is removed--"a milestone in science, a shining moment in the long fight against epidemics." A page-turning medical mystery that makes a compelling case for following the facts. (the case against the Broad Street pump, more information on Dr. Snow, list of major infectious diseases and their causes, internet resources, books on Dr. Snow and on epidemics) (Informational picture book. 4-8) Copyright (c) Kirkus Reviews, used with permission.