Saturday, February 13, 2010

"The Ghost Map" Portrays a Triumph of Science over Stubborn Ignorance

 A variant of Dr. Snow's map, showing 1854 cholera cases in London
clustered around the Broad Street pump (click to enlarge)
Steven Johnson's 2006 book, selected for Portland's Everybody Reads 2010 program, is a gripping and rigorous work of historical nonfiction and interdisciplinary analysis.  It shares many urban concepts with Jeb Brugmann's Welcome to the Urban Revolution and David Owen's Green Metropolis, but approaches them differently.  "The Ghost Map: The Story of London's Most Terrifying Epidemic--and How It Changed Science, Cities, and the Modern World"chronicles the 1854 cholera epidemic that struck London, a vast city  overwhelmed by accumulations of human waste.  City leaders and physicians, deeply convinced of the notion that miasmas, or foul smells, cause cholera despite clear evidence to the contrary,  were ineffective and often counterproductive in combating the disease.   "The Ghost Map" tells the story of physician John Snow and cleric Henry Whitehead, who traced the source of disease to a neighborhood pump contaminated by seepage from an adjacent cesspool.    

Snow's careful research, informed by Whitehead's neighborhood expertise and investigations, linked the outbreak of disease with the use of the contaminated Broad Street pump in London's Soho district.  Snow's map established this causation without knowledge of the underlying bacterial cause of cholera.  Snow's work resulted in the removal of the Broad Street pump handle late in the course of the epidemic, which, even if it saved few lives immediately, was the first science-based intervention in a cholera epidemic.  

Eventually, Snow's ideas were broadly accepted and London redesigned its sewer system to protect public health--albeit by reliably conveying raw sewage to outfalls downstream of the Thames River water intakes, where the tides swept them into the ocean.

Johnson argues, like Owen, that that the resource efficiency of urban concentrations is essential to our "City-Planet" as its population grows, and that cities must be kept safe to preserve the attractive power of their economic advantages.  As Brugmann would, he sees the Snow-Whitehead collaboration as a triumph of urbanism, in which two men with diverse backgrounds combined forces in the midst of a great city.  Johnson, however, identifies two major urban threats:  Infectious disease and nuclear weapons.  The author is optimistic about the ability of medical science to quickly and accurately analyze microbes, even those engineered by humans, and develop protective vaccines.  However, the threat of a nuclear explosive remains daunting as nuclear proliferation continues and non-state actors become more sophisticated and globally capable.

Johnson touches on an even bigger problem:  stubborn ignorance.  He notes that the theory of evolution is at the core of our ability to combat infectious disease, and that failure to accept evolutionary theory is therefore a national security issue for the United States.   Unfortunately, such ignorant stances are widespread and diverse in this country.  Like the miasmatics of the late nineteenth century, we repeatedly resort to positions that fly in the face of facts and prudence.   Most notably,  ideologues inveigh against the "unequivocal" scientific evidence and imminent danger of climate change.
On the other hand,  the miasmatics have long been discredited and everyone agrees about the role of microbes in infectious disease.  Safe water supplies are standard in modern cities, although cholera outbreaks persist.  "The Ghost Map" inspired me with a tale of how two thoughtful and persistent investigators without wealth or prominence were able to make a massive impact at the dawn of modern science, but made me wonder about the power of reason to triumph over superstition and ideology in today's world. The triumph seems inevitable, but, on the subject of climate change,  will it be be fast enough to avert global tragedy?

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