John Snow is a modern medical hero. But in his own lifetime (1813-58), he was seen as an ambitious general practitioner who cashed in on the innovation of anaesthesia. The fact that he was called to Buckingham Palace in 1853 to administer chloroform to Queen Victoria during the birth of Prince Arthur, her eighth child, counted, of course, but the anaesthetist was the servant of the surgeon or obstetrician, just as the general practitioner was subservient to the medical or surgical consultant.
Snow also contributed significantly to the understanding of cholera, showing through two brilliant epidemiological studies that the disease was transmitted by contaminated water. By the time of Snow's premature death in 1858, his cholera work was not widely appreciated, and had he lived longer his reputation might well have benefited. It took three decades for doctors to appreciate his cholera research, and his skill as an epidemiologist was realised even later.
The work of Bradford Hill and Richard Doll on the relationship between cigarette smoking and lung cancer in the 1950s and Snow's investigation of the geographical incidence of cholera during the 1854 epidemic in London are the two paradigmatic episodes for contemporary epidemiologists.
The fact that Snow came from a working-class background makes him even more appealing to modern historical sentiments. He has enjoyed four full-length biographical studies during the past two decades, more than William Harvey, Joseph Lister or other major figures in British medicine.
Sandra Hempel draws heavily on this secondary literature in her popular account of Snow's life and contributions. She concentrates primarily on Snow's work on cholera, but she has a good eye for detail and offers a moving account of Snow's negotiations in the medical world of 19th-century London. She is especially good on the nuances of his investigations of the local outbreak of cholera in Soho.
"The Broad Street Pump" episode has become a legend in medical history. Hempel provides a full account of the episode during which Snow carefully mapped out the cases of cholera that derived from a single faeces-contaminated water pump in Broad (now Broadwick) Street, in the centre of Soho. She is particularly good at evoking the social and personal circumstances of some of the epidemic's victims and in detailing Snow's negotiations with the local officials as he tried to get the pump handle removed. By the time the handle was actually taken off, so closing the well, the epidemic was on the wane.
Hempel also describes the activities of other doctors investigating the cholera outbreaks in 1848 and 1854. William Budd in Bristol gets his due, and Arthur Hill Hassell's contemporary analyses of water supplies and adulterated foodstuffs is neatly integrated into her story. So is The Lancet 's role, even if its famous editor, Thomas Wakley, appears as Wakely in the early pages. The spelling of his name is corrected later on in the book and in the index.
On balance, Hempel has done a serviceable job. The book's faults are mostly endemic to the genre of heroic biography. She accurately describes Snow's ideas but sometimes conflates discovery with social or political change.
Snow convinced a few people that cholera is spread through contaminated water, but policy hardly followed immediately.
By concentrating on the dramatic episode of the Broad Street Pump, Hempel minimises Snow's more subtle and impressive epidemiological investigations of the relationship between cholera incidence and water supplies.
In the long run, his demonstration that people living on the same streets, and in identical social circumstances, had different cholera experiences, and that this was directly related to the quality of water they had access to, was the decisive blow against the miasmatic, airborne theories of cholera transmission.
Finally, although the bibliographies for each chapter faithfully record the sources on which it is based, there are too many long quotations that cry out for more specific documentation and contextualisation. Hempel (or her publisher) should have insisted on endnotes.
Snow left few personal papers, but there is enough of his work in the published literature to allow a reasonable understanding of the man and his contributions. He deserves his place in the medical pantheon, and Hempel's account is a decent place to start.
W. F. Bynum is emeritus professor of history of medicine, University College London.
The Medical Detective: John Snow and the Mystery of Cholera
Author - Sandra Hempel
Publisher - Granta
Pages - 306
Price - £18.99
ISBN - 1 86207 842 4