Top critical review
Excellent tale marred by an outbreak of verbal diarrhoea in the epilogue
on 13 September 2011
The Ghost Map tells the story of the 1854 outbreak of cholera in Broad Street, London. More than six hundred people died, but the episode marked a turning point in the understanding of how the disease was transmitted. Dogged investigation by Dr John Snow and Rev Henry Whitehead suggested that, contrary to the accepted view that transmission was airborne ('miasmatic'), victims had been infected by drinking water from a well contaminated with faeces. A striking map of the location of the victims (the 'Ghost Map') helped to win converts to the water-borne theory, which is now universally accepted.
Apart from the importance of the discovery about the nature of cholera, Snow and Whitehead's work was one of the earliest examples of scientific epidemiolgy and is revered by historians of that discipline. It also provides an illustration of the often glacial pace at which scientific revolutions occur: the miasmatic theory clung on for decades and was only gradually and quietly dropped.
The story is engagingly told by Johnson in a similar vein to Dava Sobel's Longitude. The Victorian sewage system is not at first sight a promising theme, but it proves surprisingly rewarding. We learn of the army of waste recyclers and the almost unbearable smelliness of London in the 1850s.
There are irritations. First, the overheated subtitle describing 1854 as 'London's Most Terrifying Epidemic'. No doubt the episode was locally alarming, but the death toll was tiny, both in absolute and proportional terms, compared to the plague epidemics which struck the city in previous centuries. Indeed, as Johnson himself notes in the main text in some ways what is surprising is how little newspaper coverage was generated by the cholera outbreaks of the mid 19th century.
Second, the epilogue. This consists of a rambling account of the various threats facing modern cities: nuclear attack, bio-terrorism, bird flu, global warming and so on. His general line is that if these problems are addressed with the same Victorian can-do with which Snow and Whitehead tackled the 1854 cholera epidemic then the 'forces of reason will win out'. So, he concludes, 'Let's get on with it'. It is all rather naff.
Third, Johnson's condescension towards those who believed the miasmatic theory. Certainly from a distance of 150 years the theory appears incorrect and indeed counter-productive, but in another 150 years time won't the current theories also look absurd? There is little sense here of the relative nature of scientific progress, with each generation looking back on the preceding generation's theories in horror (a process particularly noticeable in the medical field).
Still, as other reviewers have said, if you can ignore the epilogue it's a lively read.