- NOTE TO USERS The original manuscript received by UMI contains broken, slanted print, and margins exceed guidelines. All efforts were made to acquire the highest quality manuscript from the author or school. Microfilmed as received. This reproduction is the best copy available UMI MELTING SNOW: A RE-EXAMINATION OF DR JOHN SNOW, HIS DOT-MAP, AND THE 1854 BROAD STREET CHOLERA OUTBREAK Kari S. McLeod, B. A. (Honors) 1995 A thesis submitted to the Faculty of Graduate Studies in partid fuifil Iment of the requirement for the degree of Master of Arts Department of Geography Carleton University Ottawa, Ontario May 1,1998 O 1998, Kari S. 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ABSTRACT The mythical story of John Snow and the Broad Street outbreak is common in medical geography, epidemiology, and the history of medicine. In 1854, Snow identified the source of the cholera outbreak in Golden Square (in present-day Soho) as the Broad Street pump, possibly with a dot-map of cholera deaths, and successfÙlly argued for the removal of the pump's handle. Many accounts state that this action ended the outbreak. In al1 three disciplines, Snow is presented as a hero because he showed how cholera is transmitted, because his ideas affected public heaith policy, and because he provided definitive proof of a hypothesis. For medical geography, Snow's heroic reputation is related to his determinative use of a dot-map, and many authors feature the map in their presentations of the story. However, the twentieth-century versions of this map cm be quite different fiorn one another. This thesis re-examines the myth of John Snow, his dot-map, and the 1854 Broad Street outbreak-informed by archivai research-and challenges the taken-for-granted repetition of the story in the three disciplines. The process of retelling the story encourages future investigation of the meaning of the myth in disciplinary contexts; of the nature of proof of causation; and of how evidence, argument and authority work in science. iii Acknowledgements Developing this thesis involved an idea followed by negotiating a maze of hints, references, leads, and blind alleys. To that end I owe a great deal to David Bennett for his guidance, suggestions, and patience and for allowing me to take over an idea that was his. 1 would like to thank Carleton University's fuiancial support in the form of the Graduate Student Research Fund, the Ina Hutchinson Award. the Ethel Cockbum Graduate Research bursary, travel funding, and two yean of teaching assistantships. Thanks to the staffat the Wellcome Institute Library, the Westminster City Archives, the library at the Royal College of Physicians and Surgeons, and the London Metropolitan Archives (especially Mick Scott for granting copyright release on Snow's maps). Thanks to Barry Boots at Sir Wilfied Laurier University for sharing his hunch that one of Snow's maps is an early example of a Voronoi diagram on a network. 1 have depended on the love and support of my fmily during my Master's; 1 appreciate al1 of you. My field work was possible and pleasurable because of the generosity and hospitality of my Aunt Bev and her partner Lee. Thanks to Nan Sussmann, Lorna Johansen-Garcia, Alette, Jeff, and Jenn. Thanks Hrizel Anderson for rnaking me feel more at home and for being the rock of the departrnent. The past two and a half years would not have been the same without my best friends Paula and Alice. Thanks for CWAG, CR, Philbert Wolfort, and believing in me. Finally, rny etemal thanks to Chris for subjecting himself to numerous discussions about John Snow; for his endless ability to listen, contribute, advise, not advise, and proof-read; for lime-pickle omelettes; and for being there when 1 needed him the most. In the end you just have to sit down and write the damn thing: we did it! Epigraph As geographers, Sosius, crowd into the edges of their maps parts of the world which they do not know about, adding notes in the margin to the effect that beyond this lies nothing but sandy deserts full of wild beasts and unapproachable bogs. P lutarch. Lives, Aemilius Paulus, sec. 5 If you cal1 a tail a leg, how many legs does a dog have? Abraham Lincoln Dr. S.: Did you know that there's a direct correlation between the decline of the Spirograph and the rise in gang activity? Think about it. Bart: 1 will. Dr. S.: No you won't. The Simpsons Table of Contents CHAPTER ONE - INTRODUCTION CHAPTER TWO - MEDICAL GEOGRAPHY AND DISEASE MAPPING 13 2.1 CURRENT ISSUES IN MEDICAL GEOGRAPHY 14 2.1.1 Questioning positivist-science and geometric/absolute space 14 2.1.2 Adoption of new social theones and social spaces and places 17 2.1.3 Critique of the biomedical mode1 of disease 20 2.1.4 Examining and interpreting social constructions of health and illness 24 2.1 -5Changing methods 27 2.2 DISEASE MAPPING IN MEDICAL GEOGRAPHY 2.2.1 Brief History 2.2.2 Meaning and purpose CHAPTER THIUEE - SNOW JN GEOGRAPHY: DOT-MAPS AND STORIES 37 3.1 THE TWENTIETH-CENTURY MAPS 38 3.2 REPRESENTATIONS OF SNOW IN GEOGRAPHY 49 3.2.1 Geography's view of John Snow: actions reputation, theory, and background 50 3.2.2 Broad Street: cholera in Golden Square, Soho 1854 and Snow's investigation 52 3.2.3 The impact of Snow's evidence, argument, and theory 55 3.2.4 Comrnonalities, anomaiies, and absences 56 CHAPTER FOUR - SNOW IN EPIDEMIOLOGY AND THE HISTORY OF MEDICINE 60 4.1 REPRESENTATIONS OF SNOW IN EPIDEMIOLOGY 60 4.1.1 Epidemiology's view of Snow: actions, reputation, theory, and background 61 4.1.2 Broad Street: cholera in Golden Square, Soho 1854 and Snow's investigation 64 4.1.3 The impact of Snow's evidence, argument, and theory 67 4.1.4 Cornmonaiities, anomalies, and absences 68 4.2 REPRESENTATIONS OF SNOW IN THE HISTORY OF MEDICINE 69 4.2.1 Medical History 's view of Snow: actions, reputation, theory , and background 70 4.2.2 Broad Street: cholera in Golden Square, Soho in 1854 and Snow's investigation 74 4.2.3 The impact of Snow7sevidence, argument, and theory 79 4.2.4 Commonalities, absences, and anomalies 81 4.3 BUT WRITERS OF HISTORICAL TEXTS OFTEN DO 83 4.3.1 Historical questions 84 4.3.2 Present meanings of the history 85 4.3 -3 Meanings for science: evidence, argument, and causation 86 CHAPTER FIVE - WHO WAS JOHN SNOW? 87 5.1 BIOGRAPHY 89 5.2 HISTORICAL CONTEXT 95 5.3 SNOW AND EPIDEMIOLOGY 5.3.1 Contemporary cholera theones 5.3.2 Snow's theory of cholera 5.4 SNOW AND ANAESTFESIA 112 CHAPTER SIX - RETELLING THE STORY: SNOW, CHOLERA, AND BROAD STREET IN 1854 119 6.1 GENERAL DETAILS 6.1.1 London as a whole 6.1 -2 Golden Square 6.2 SNOW'S ACTIONS DURING THE BROAD STREET EPIDEMIC 123 6.2.1 The methodology of focusing on the pump 123 6.2.2 Reverend Whitehead 124 6.3 THE PUMP 127 6.4 POST-OUTBREAK WESTIGATIONS 132 6.4.1 Further work by Snow 133 6.4.2 Report on the Cholera Outbreak in the Parish of St. James's, Westminster 134 6.4.3 The General Board of Health 138 6.5 THE MAPS 140 6.6 WHAT DID SNOW'S BROAD STREET INVESTIGATION SHOW? 149 6.6.1 Cholera as self-limiting 149 vii 6.6.2 Effects and acceptance of Snow's study in the nineteenth century 150 CHAPTER SEVEN - A SENSE OF SNOW 158 7.2 CONTEXTUAL LEGACIES OF SNOW 7.2.1 History of medicine 7.2.2 Epidemiology 7.2.3 Geography 7.3 BROADER UNDERSTANDINGS OF CAUSATION AND SCIENCE 168 7.4 FUTURE RESEARCH 170 References-Archival Sources 172 References-Primary Sources 173 References-Secondary Sources 176 viii List of Tables 3.1 Comparing the twentieth-tennis, reproductions of Snow's dot-map 40 6.1 Cholera deaths in Golden Square, Soho from August 3 1 to September 1 1, 1854 13 1 6.2 Cornparhg the histoncal maps of the choiera outbreak in Golden Square 141 List of Figures 3.1 Gilbert's reproduction of Snow's dot-map (1 958, p. 174) 41 3.2 Stamp's reproduction of Snow's dot-map (1964% p. 16; 1964b. p. 35) 42 33 Howe's reproduction of Snow's dot-map (1972, p. 174) 44 3.4 Smith's reproduction of Snow's dot-map (1979, p. 47) 45 3.5 Learmonth's reproduction of Snow's dot-map (1 988, p. 147) 46 3.6 Jones's reproduction of Snow's dot-map (1990.