Book of the Month Cholera, Chloroform, and the Science of Medicine: A Life of John Snow
Authors: Rosalind Stanwell-Smith
Journal: Journal of the Royal Society of Medicine (2003)

For anyone seeking contemporary themes and insights in the lessons of medical history, the work of Dr John Snow (1813–1858) provides a potent example. Yet his status as an international icon of medical, scientific and epidemiological method was hard won. Most of his contemporaries would have been amazed by the result of a 2003 poll, organized by a magazine for hospital doctors, voting him 'the greatest doctor of all time'. For Snow exemplifies the biblical adage that a prophet is without honour in his own country and house: the 19th century British medical establishment was in general fiercely opposed to his views. His somewhat curmudgeonly personality, his decision to specialize in the new and controversial technique of anaesthesia and his early death all militated against proper recognition of his contribution to medicine.

Snow's rise to iconic status is only in small part due to the pioneering anaesthetic work that occupied most of his later professional life. It is due far more to the use of his work as a case study in the emerging science of epidemiology during the 20th century. Recognition of the importance of Snow as an epidemiologist started in the schools of public health in the USA. In the traditional British manner of delayed acknowledgement of non-military heroes (particularly in science), this reputation was then reclaimed and taught here too, so that generations of doctors and scientists learned the story of the Broad Street pump and the cholera outbreak of 1854 in Soho. This belated recognition was strongest in London, where a lecturer in public health at the London School of Hygiene and Tropical Medicine, Dr Sidney Chave, was instrumental in persuading a Soho pub near the site of the pump to change its name to the 'John Snow' in 1954. Here at last was an association with undeniable British appeal and, since the 1950s, students at the LSHTM have visited the site to round off their epidemiological pursuits. In the 1990s, a visit to the public house provided the 'germ' for the John Snow Society as a more fitting way to commemorate this teetotal hero. The small group who founded the Society had only a slight idea of the reverence with which Snow was already held, not least amongst anaesthetists, but we soon learned and the Society now has over a thousand members world-wide, from all the 'Snow-related' disciplines. Now, too, an excellent and comprehensive account of Snow's work1 has been produced, although I must sadly report that none of the authors appears to be a member of the John Snow Society; they have their own professorial group with the nickname of 'The Snowflakes'. It is, however, appropriate that this book was written in the USA, where the 'multiple legacies' of Snow were first acknowledged and much of the published analysis and interpretation of his work has originated.

The authors identify these multiple legacies as anaesthesia, epidemiology and cartography. The last is a recently claimed legacy, within the past decade, and a paradox is highlighted in the replacement of Snow's illustrative use of disease mapping by 'mythical caricatures of his methods and actions'. For the exponents of the graphic information system (GIS) technology, John Snow has become virtually a patron saint, despite the fact that modern GIS bears a greater resemblance to the methods of other mid-19th century workers in public health. Every new science needs a hero and Snow provides an accessible foundation myth. Yet the current work avoids hagiography. Often acclaimed as ahead of his time—heralding the germ theory, modern anaesthesia and the statistical techniques possible in our computer age—Snow was also a man of his time in making errors and drawing conclusions within the limits of the knowledge then available. A more serious consequence of the icon status is the 'fracturing of the unity of his work' which has inevitably followed the separate development of the specialties of anaesthesia and epidemiology: in the John Snow Society we have so far managed only one Blessed Chloroform Lecture, in contrast to a regular series of Pump Handle Lectures that commemorate his epidemiological side. ('Blessed chloroform' was the expression confided by Queen Victoria to her diary after the birth of Prince Leopold, at which Snow applied his skills.) One of the greatest achievements of the book is that the authors represent different aspects of this fractured legacy, giving us at last an interdisciplinary and synthesized account.

The synthesis does not quite extend to bridging the differences in the Snow heritage on the two sides of the Atlantic, either in the interpretation of his work or in the way he is revered. Snow was a serious and intensely private man, a notably un-British hero: apart from a youthful prank with a firecracker in a church porch, not a whiff of scandal has been uncovered. Though the book is subtitled A Life, the emphasis is firmly on his work. Nevertheless, the lively American style makes this far from a dull read: to give just one example, Snow's investigation with others of candles infused with white arsenic (used for cheapness and brightness of the flame) is referred to as 'the poison candle caper'. Snow could be provocative, even mischievous, in his researches and contributions to meetings, despite his customary portrayal as stern and sombre, characterized by the gloomy sculpted head on the cover. The book is well illustrated, annotated and indexed, including reference (albeit only in footnotes) to the invaluable detailed transcription of Snow's notebooks by the late Dr Richard Ellis and to the historical research on Snow's early life and practice by Dr Spence Galbraith, the latter inspired by research for one of the early Pump Handle Lectures.2 On this side of the Atlantic, Galbraith helped to keep the spirit of Snow alive in the epidemiology of infection by selecting the Broad Street pump as the symbol for the Communicable Disease Surveillance Centre, an organization now united with non-infectious-disease epidemiology within the Health Protection Agency. Thus the fractured reputation of Snow within different specialties is being repaired in all quarters; and, as for the icon, we may yet see 'Snow—the movie'. If so, the painstaking account in this book will provide no excuse for inaccuracies, and directors could choose an opening scene from the description of a meeting of the British Medical Association in 1856, when Snow's work on cholera and water supplies received possibly the only 'Hear, hear!' during his lifetime. In the minutes of the meeting, Dr William Budd and others deplored 'that Dr Snow's great labours had been so completely unrecognised'. 'Hear, hear' to that and to this well researched tribute to a doctor with 'true genius for observation'.