Source: The Lancet 362 (9386), 839, September 6, 2003

MEDIA REVIEWS

The Real John Snow

Cholera, Chloroform and the Science of Medicine: A Life of John Snow

Peter Vinten-Johansen, Howard Brody, Nigel Paneth, Stephen Rackman, Michael Rip (with David Zuck).

New York: Oxford University Press, 2003. Pp 437. $49.95. ISBN 0 195 13544 X.

This book is really a remarkable achievement, a truly synthesised product of the research of five professors from Michigan State University who share a fascination for the life of the British anaesthetist and epidemiologist John Snow (1813-58). Over the course of 6 years, their collective passion has earned them the dubious nickname of "the Snowflakes", but I am sure that there will be many who would have willingly borne this title for the honour of being associated with this publication.

Earlier this year, Snow was voted the "greatest doctor of all time" in a UK poll organised by the Hospital Doctor magazine. He has long been championed by anaesthetists, public-health practitioners, and more recently by pioneers of geographical information systems. His map of the cholera outbreak in London in 1854 has been plagiarised by many epidemiological training courses, and many of the versions in circulation bear little resemblance to the original. Similarly, the tale of the Broad Street pump has passed corrupted into folklore. Many medical students are inculcated with the naive supposition that Snow himself removed the handle of the pump, thus simultaneously ending the cholera epidemic and becoming an international public-health hero. However Snow's canonisation is a more recent event. His 1855 seminal publication, On the Mode of Communication of Cholera, was plagiarised by John Simon for government reports, ignored by Robert Koch, and marginalised by several influential 20th-century writers on public health.

It is hard to produce a biography that requires so much elaboration to be stripped away. Much harder still when at the base of the excavation one finds a bare smattering of archive sources. The authors have carefully reconstructed Snow's working-class childhood in York and early medical training in the northeast of England to a far greater extent than previous researchers have managed. After Snow moved to London in 1836, aged 23 years, to gain his medical qualifications we are on more familiar territory, which is engagingly conveyed by useful descriptions of the medical radicalism he allied himself with at the Hunterian School of Medicine. However, the real talent of this team of authors has been their successful conversion of Snow's case books, which he meticulously kept throughout his working life in London, into a vivid and immensely readable narration. The opening lines epitomise the easy style of the book:

"Sometime between 1839 and 1841, John Snow drowned a guinea pig. It died in two minutes. An hour after its death, Snow began dissecting. He observed that the heart was perfectly still and that the right side was swollen with blood while the left side was nearly empty . . . then much to his surprise the heart twitched . . . he opened the trachea and began artificial respiration."

Snow's interest in the physiology of respiration predated his arrival in London, but it was in the supportive environment of the Westminster Medical Society--which merged to become the Medical Society of London in 1851--that he began his systematic research into resuscitation and the chemistry and physics of inhaled gases. Snow's experimentation with ether in 1847 illustrates his modern integrative approach to medicine, which exploited the nascent collateral sciences to establish a reliable method of anaesthesia. His scrupulous primary focus on the safety of patients and his commitment to scientific progress through open discussion is thrown into sharp relief by the recent biography of William Morton, the American pioneer of ether. Unlike Morton, Snow was content for others to profit from his research. His reward was the recognition of his ability by leading surgeons and the development of a substantial anaesthesia practice.

Previous studies have tended to compartmentalise Snow's work on anaesthetics and epidemiology, creating almost a Jekyll and Hyde type character. One of the many strengths of this book is its careful chronological construction that illuminates the logical progression of Snow's work. He moved easily between research and anaesthetic practice, maintaining a constant dialogue with colleagues through publications and presentations to medical societies (he published some 89 papers, 15 of which were published in The Lancet). When the second cholera epidemic arrived in the UK in 1848, Snow was more knowledgeable about the properties of air and gases than most miasmatists. His alternative, audacious, theory that matured over the next 7 years fused pathology, clinical observation, and epidemiology into a sophisticated systems-hierarchical model. This model showed that a specific disease could only be generated by a specific organism, and that the organism responsible for cholera required ingestion rather than inhalation. Snow's focus on contaminated water made a mockery of the Chadwickian privy-to-water closet conversion programmes that, in effect, diffused cholera more widely in some of London's private water company systems. This book provides a beautifully graphic analysis of how Snow substantiated his theory through the shoe-leather inquiries he personally made into the water supply of 658 of 860 cholera victims in the 1854 outbreak. This is the real epidemiological highlight of Snow's work--the Broad Street episode pales by comparison, saved by the visually attractive icon of the pump.

This exemplary interdisciplinary biography of one of the greatest doctors is long overdue, but well worth the wait. It replaces the caricature of the socially inept loner with an authoritative portrayal of Snow as a conscientious and confident medical scientist and practitioner. This substantial publication, in which the endnotes are compulsory reading for their fascinating background information, will undoubtedly become the standard reference for Snow. It is a tribute to the authors that they have surpassed this target to create a very readable insight into London's vibrant medical and scientific community during the epidemic years of the mid-19th century. Snow himself would have appreciated the flexibility and lucidity in this work that so characterised his own.

Sally Sheard

University of Liverpool, Department of Public Health and School of History, Liverpool L69 3GB, UK

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