Mapping Cholera in 1849: John Lea and Henry Boyd in Cincinnati ​

by Paul Muller, CPA Executive Director

This is a story about John Lea, a Cincinnati notary and amateur geologist, who was obsessed with finding the cause of Choler, and about Henry Boyd, a highly successful Cincinnati furniture maker and former enslaved Kentuckian.  In 1832 Henry Boyd, determined that water was the source of cholera transmission. Boyd’s recommendation to boil all drinking water was published in Cincinnati newspapers, and had it been widely implemented, would have saved thousands of lives in the waves of cholera outbreaks in the 19th century. 


John Lea believed cholera had geologic origins, and in the course extensive research Lea produced an 1849 map of the cases of the disease along a section of Sycamore Street.  Lea created a map of victims of the 1849 cholera epidemic in Cincinnati. This early mapping of a disease outbreak was years before London physician John Snow created his famous Broad Street Pump Map.  Lea’s work set the stage for decades of public health research and is acknowledged as important advance in use of the scientific method in the study of disease. 


Lea and Boyd are increasingly cited for their pioneering concepts about the source of cholera and their recommendations on how to stop its spread. Tom Koch in his “Commentary: The Researcher as Amateur: John Lea, Cholera, and … the Computer Age” placed Lea in the timeline of the history of scientific research:


“The importance of Lea’s published work … lies in the quite extraordinarily complete and efficient methodology he employed, including the detailed study of a Cincinnati neighborhood outbreak of an infectious disease. His approach demonstrates a research model still used by local and professional researchers (in cancer, cholera, typhoid, etc.) into the twentieth century.”  


David Morens, an epidemiologist at National Institute of Allergy and Infectious Diseases at the National Institutes of Health acknowledges both Lea and Boyd in his “Commentary: Cholera conundrums and proto-epidemiologic puzzles. The confusing epidemic world of John Lea and John Snow” .  Morens noted that  “Lea was among the first to correctly establish an unambiguous association between water source and cholera occurrence by organized observational study, and among the first to propose a valid means of preventing it.”


“…While it is not clear whether Lea’s conviction that drinking pure water completely prevented cholera was his alone, or whether the original observation should be credited to Henry Boyd  or unknown others, it was clearly Lea who tirelessly promoted the implications for public health. … It is not known whether Boyd ever advanced his cholera theory after 1832, or whether he and Lea ever discussed it or even knew each other.”  


Today John Lea and Henry Boyd are both buried in Spring Grove Cemetery, Lea has a significant monument, Boyd’s is in an unmarked grave.


Henry Boyd’s place in Cincinnati history is not at the level of prominence his work deserves.  We should be telling the deeper history of Cincinnati and honoring people like Henry Boyd who contributed in so many areas of public life.  We can fix a small piece of the problem by placing a historic marker at the site of Boyd’s furniture works on the northwest corner of 8th and Broadway.  If you want to be part of the effort, just let us know.


Further Reading and Source Information:

Cholera, with reference to the geological theory: A proximate cause – a law by which it is governed – a prophylactic1  by John Lea, 1850, reprint in International Journal of Epidemiology, Volume 42, Issue 1, February 2013, Pages 30–42


Henry Boyd, 1802-1886, The Black Agenda and The Cincinnati Herald Historical Site, Cincinnati African-American Historical Archives


Commentary: The Researcher as Amateur: John Lea, Cholera, and … the Computer Age  Tom Koch, International Journal of Epidemiology, Volume 42, Issue 1, February 2013, Pages 52–58, Published: 14 March 2013


Commentary: Cholera conundrums and proto-epidemiologic puzzles. The confusing epidemic world of John Lea and John Snow David M Morens, International Journal of Epidemiology, Volume 42, Issue 1, February 2013, Pages 43–52, Published: 14 March 2013


Cincinnatians and Cholera: Attitudes Toward the Epidemics of 1832 and 1849   Queen City Heritage, Fall 1992, by Ruth C. Carter


Cincinnati Panorama of 1848, The Public Library of Cincinnati and Hamilton County


The Specter of Cholera in Nineteenth-Century Cincinnati, Matthew D. Smith, Ohio Valley History, Volume 16, Number 2, Summer 2016, pp. 21-40 (Article) Published by The Filson Historical Society and Cincinnati Museum Center


Youtube Video on John Snow and the Broad Street Pump, HarvardX


A bed frame in the style of Henry Boyd’s famous Boyd Bedstead


John Lea’s Map of the 1849 Cholera Epidemic showing a section of Sycamore Street just north of Liberty Street. It is considered an important step in the application of the scientific method to the study of disease outbreaks.

Scroll to Top