Megalopolis and micro-organism
Tony Gould
THE GHOST MAP: A STREET, AN EPIDEMIC AND THE TWO MEN WHO BATTLED TO SAVE VICTORIAN LONDON by Steven Johnson Allen Lane, £16.99, pp. 299, ISBN 0713999748 ✆ £13.59 (plus £2.45 p&p) 0870 429 6655 The story of Dr John Snow’s investigations into the causes of the cholera epidemics in midVictorian London has been written up several times, most recently in a book by Sandra Hempel which I reviewed in these pages six months ago. So do we need yet another account of them? Perhaps not, except that Steven Johnson approaches them from an unusually interesting angle: his book is less concerned with medical history than with urban history and, in particular, the rise of megacities. ‘We are now, as a species,’ he claims, ‘dependent on dense urban living as a survival strategy.’ If you’re wondering what relevance Snow’s discovery, dismissed and mocked as it was at the time, that the culprit in the devastating 1854 outbreak of cholera in Soho was the water pump in Broad (now Broadwick) Street has to this large claim, Johnson’s answer is, ‘Broad Street marked the first time in history when a reasonable person might have surveyed the state of urban life and come to the conclusion that cities would some day become great conquerors of disease. Until then, it looked like a losing battle all the way.’ In other words, Snow’s pioneering work in epidemiology, epitomised by his map of Broad Street and its environs that gives Johnson’s book its title, was an essential component in paving the way to cleaner, healthier cities.
The Ghost Map’s opening sentence sets the scene: ‘It is August 1854, and London is a city of scavengers.’ Johnson evokes the world of Henry Mayhew and lists no less than 11 trades that are all forms of scavenging. He emphasises the crucial role played by the poorly rewarded ‘purefinders’ and ‘night-soil men’ in recycling the city’s waste, but points out that London was ‘a Victorian metropolis trying to make do with an Elizabethan public infrastructure’. The most noticeable thing about it, apart from its noise, was its stench, and this was what misled so many of the leading medical and public health authorities, including Edwin Chadwick and Florence Nightingale, into believing that diseases like cholera did not have a specific cause but were the product of ‘miasma’. ‘Miasmatists’ were in the ascendancy and ‘contagionists’ like John Snow were very much in the minority in those pre-microbe days; hence the huge and apparently illogical reluctance of the medical establishment to accept that cholera was a waterborne disease.
Johnson rehearses the medical arguments, but his real interest lies elsewhere. While he pays tribute to Snow’s incredible dedication and persistence in the face of constant sneering and discouragement, he gives equal billing to the young curate of St Luke’s on Berwick Street, the Reverend Henry Whitehead. Whitehead is generally described as a disciple of Snow, but Johnson sees his role in the Broad Street epidemic as that of a fellow independentminded investigator with an even greater local knowledge than Snow, who lived nearby, possessed.
Initially Whitehead was certainly not a disciple; indeed he set out to disprove Snow’s theory that the Broad Street pump was responsible for the rapid and strikingly uneven spread of the cholera. As a man deeply involved with his parishioners, he knew of the pump’s reputation as a source of the purest water in the district and had drunk it himself during the outbreak without ill effects. So he remained a sceptic until the facts thrown up by his own detailed investigations proved him wrong. Once convinced, however, he did not simply befriend and support Snow but actively contributed to making his case watertight (if one can use such a word in this context). It was through his efforts, not Snow’s, that the origins of the outbreak were discovered and as a result the pump, which had previously been given a clean bill of health (though Snow had succeeded in having its handle removed), was reexamined and found to be contaminated by the human waste of cholera victims in the street.
Whitehead’s importance for Johnson is that he was not an expert, except in local knowledge. Johnson is an enthusiastic proponent of big city living, its environmental benefits, such as the saving of energy dense living entails, and the way that large-scale metropolitanism is offset by the extreme localism of particular districts, streets, etc. He sees this reflected in modern technology, particularly in the Web, which juxtaposes the universal with the very local and particular. For him, the combination of Whitehead’s special knowledge of that part of Soho and its people with Snow’s epidemiological expertise was not only perfectly complementary but also serves as a model of the kind of conceptual thinking required in the ever-growing number of mega-cities of the 21st century.
Johnson is not the first person to draw attention to Snow’s contribution in the field of disease-mapping. Credit for that, as he acknowledges (albeit in a slightly backhanded manner), should go to Edward R. Tufte, whose Visual Explanations (1997) contains a groundbreaking account of it. But his thoughtprovoking shifts from megalopolis to micro-organism and back again make for an exhilarating read.
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