55 John Snow: The Beginning and End of Cholera

Introduction

Ever since the beginning of recorded history, mankind has faced many enemies. Everything from natural disasters, predators, famine, and more have ravaged our species for generations, but one threat has loomed above them all– disease. Among many of the deadliest diseases, cholera is one of the most lethal and physically draining contagions, and for centuries caused the deaths of millions of people across the world. Nowhere was this more true than the cities of Europe like London, where rampant pollution of streets and waterways, poor medical knowledge, and impoverished and crowded housing created the perfect environment for the disease to take hold.  Even by the 20th century, the people of London, despite living in one of the wealthiest cities on the planet, were still largely victims of disease outbreaks and their heavy death toll. Medical understanding had greatly improved, especially since the scientific revolution of the past 150 years, but many crucial aspects of treatments and disease prevention that are taken for granted today were simply not understood in this time.

Until the early 1830s English practitioners had little to no experience with asiatic cholera, so when the disease appeared Newcastle in the winter of 1831, many of the practitioners were unsure of its nature and how to treat it. Many claimed the miasma theory, in which the overcrowding and abundant manure created an “unwholesome air,” that would spread the disease throughout (Vinten-Johansen, 2003). However, the town and the surrounding area in Northumberland and Durham would see hundreds of patients contract the disease over the coming months, marking the first major epidemic of cholera in the British Isles. In the small coal mining town of Killingsworth the following year, an apprentice by the name of John Snow was forced to confront this disease, despite his lack of formal training and understanding of the contagion. Only 18 years old, Snow was immediately thrown into the field, treating coal workers and villagers, and forced to combat one of humanity’s longest enemies, beginning his lifelong journey of bringing the end of cholera.

Cholera, Snow’s Training, & London

Cholera itself is a highly contagious disease that causes acute diarrhea and intense dehydration, involving cramps and vomiting, which often leaves patients in critical condition after just days of contracting the condition. The disease itself originates from the Indian sub-continent, but through increased trade and global movement of people during European expansion, the disease made its way up to many different areas of the world, including England itself (Tulchinsky, 2018). The first appearance of the contagion was in the epidemic of Newcastle, where Snow was first starting off as an apprentice. Through his experiences treating the early outbreak in 1831 and 1832, he began to question the common miasma theory of disease spread. Cholera and other viral conditions were thought to be “caused by airborne transmission of poisonous vapors from foul smells due to poor sanitation” (Tulchinsky, 2018). Areas such as districts in London near the Thames river were heavily prone to this intense odor as much of the city’s sewage was directly dumped into this water source. Additionally, the high proximity and population density of London and similar cities led to a high volume of shared resources, such as street pumps, local bathhouses, and close quarter living that prompted a high spread of contagious diseases like cholera once one person was infected. It was these factors that ultimately made the city an inevitable target for an outbreak. Finally, in the summer 1848, it struck … and hard.

Snow himself prior to this was hard at work with medical training and education, whilst also beginning to provide significant contributions to the medical community. Born in York in 1813, Snow would start at an early age of 14 with medical apprentices. During this time is when he would visit Killingsworth and have first-hand exposure to cholera’s impact, leaving a strong and unforgettable impression on the young man. He would continue with three straight apprenticeships, and would later go one to earn his medicine degree in 1844 from the University of London (Frerichs, 2026). Just five years later, the Royal College of Physicians of London granted Snow his specialist license, an honor only few doctors of the time achieved. He would establish a medical practice in the Soho district of London, which would later prove to be essential in his famous investigation of the Cholera epidemic of 1854.

He would dedicate much of his early work to studying the benefits of chloroform, ether, and other anesthetics of the time. While many of these substances were known to provide the pain relieving effects, proper dosages, mixtures, and safe practices were not yet understood. Through this lack of knowledge, John Snow made his name known with his analytical study of anesthetics, bringing light to the deeper intricacies of their medical purposes and uses. Particularly the use of ether and chloroform, both of which provided a patient with pain relief and unconsciousness for surgical operations. Through his research and clinical trials, he was able to establish an anesthesiology practice in London, broadening his connections within the medical community in the city (Vinten Johansen, 2003). This crucial work  during the late 1840s and into the 1850s Snow was named the head anesthesiologist at St. George’s hospital, and would be successful in administering chloroform to Queen Victoria, which brought on immense approval and support for gaseous anesthetics in the larger medical community and the public at large (Frerichs, 2026). Snow was also a founding member of the London Epidemiological Society, a foundation the first of its kind that aimed to help combat the spread of highly contagious diseases and advise the government on the treatment and plan surrounding outbreaks, particularly in heavily urbanized areas like London itself. This organization would be crucial in the coming decades in outbreak treatment and containment, and learning from the mistakes of the past. The city had experienced two large epidemics of the Cholera in the past, in 1831-32, and again in 1848-49. Both of these incidents gave Snow experience with the condition’s nature and harsh reality, and importantly how little practitioners could do for their patients. Each time the shadow of the disease passed over the streets of London, the afflicted died in masses, and like many others Snow had no solution. Finally, in the summer of 1854, Cholera crept into the city for a third time, right in the heart of the city by Broadstreet in the Soho neighborhood. The same neighborhood that Snow had established his anesthesiology practice. However, instead of standing back and letting the epidemic run its course, taking the lives of thousands, Snow decided to act. With death on his doorstep, he dove headfirst into the streets of Soho, determined to finally find the true source of cholera.

The Investigation of Broad Street

In the summer heat of September 1854, Snow took to the streets of the Soho district, looking for patterns, correlations, and any hint at the true nature of cholera. Initially these efforts were faced with much challenge, as across the city cholera seemed to spread without any regard for reason. Rich and poor, young and old, male and female, healthy and sickly, cholera cared not for any of these predisposed attributes of its victims, and left Snow without much information. However

he chose to focus on what he did know, the epicenter of the spread in London came out of Soho, where over 600 deaths were recorded in a 10-day span (Tulchinsky, 2018). Snow on foot went from door to door, speaking with tenants, landlords, businessmen, and families, all in the hopes of tracking the spread. Through this, Snow began to track the locations of deaths, and formatted a map of the disease spread. He traced the deaths in the area surrounding broad street, and began to analyze any pattern he could find. He began to realize that a high number of deaths occurred in a close vicinity of the broad street water pump (Seen as the central blue pump shape in Figure 1). This piece of information was crucial, as it implied that the spread of cholera was originating from the waterpump. Previously Snow had conducted a survey of London water providers, analyzing companies like Southwark & Vauxhall, Lamden, Grand Junction, etc (Vinten Johansen, 2003). All major water supply companies serviced water from the River Thames or Lea for London. However, Snow discovered that come companies, notably Southwark & Vauxhall which serviced much of the Soho district, would intake water downstream of the primary waste outlets. Significant amounts of fecal matter, trash, and human waste would be dumped into the River Thames on a daily basis, so when people serviced by Southwark & Vauxhall would get water from their pumps, it was highly likely to be contaminated. Additionally, many lower class residents of London may utilize communal cess pits, dug out for the sole purpose of disposing of human waste. However, many of these pits would be poorly constructed, and often leaked into the surrounding ground water. Pair these poor sanitary conditions with the fact that those with cholera often expelled tremendous amounts of bodily fluids, which had to be disposed of especially in such dense living quarters like most London districts, the chances for water contamination and an exponential spread of the disease due to exposure to this water were growing rapidly as the 1854 epidemic began. John Snow with all of this information, and the deaths surrounding Broadstreet began to formulate his theory on the spread of cholera, in which it is transmitted through drinking contaminated water, rather than exposure to toxic miasma / gases, which was the predominant thought process. Testing his theory, Snow chased down many of the leads in the area that may have disproved his ideas about cholera’s spread. Snow investigated the local workhouse and brewery, each just a block away from the broadstreet pump. Despite their proximity, both seemingly escaped the epidemic entirely. However, Snow discovered that each relied on private wells that were dug for the sole use of each establishment, along with the workhouse having a secondary supply from Grand Junction and the brewery with one from New River water suppliers (Tulchinsky, 2018). Snow hypothesized that each was spared from the rampaging cholera due to their access to uncontaminated water. Additionally, Snow found through surveying local residents that many people preferred the Broadstreet pump over other, closer, and perhaps safer, pumps on other streets. This strengthened the argument that the spread was due to the water originating from the broadstreet pump, rather than some other source. If one member of a family contracted the illness, it was highly likely for the rest to become sick as well due to sheer proximity and exposure to infected fluids, and this would continue to play out among numerous households as residents continued to drink from the Broadstreet pump.

Armed with this information, after three days of constant work and analysis, Snow went to the Board of Guardians of St. James parish, the health board for the district. During his meeting, he showed the committee all of his work, from his graphs and maps of the outbreak, to the chemical analysis of the water from various pumps. Still in the height of the spread of cholera, and despite the controversy of Snow’s theory, the board decided to remove the handle of the Broadstreet pump the following day. What resulted was a large decrease in the number of new cases, and the epidemic was quickly brought to an end in the Soho district.

Connection to STS: Conflict & Denial of Snow’s Theory

Despite the remarkable and intensive work of Snow in the summer of 1854, and his ingenious statistical mapping of the spread of the contagion surrounding the Broad Street pump, his ideas and practices were called into question by many in the medical community. Nowadays for new scientific information to be accepted, it is often required that it is tested numerous times to see if the results are reproducible, and the literature in which said information is published is heavily scrutinized, where peers will analyze the methodology of scientists conducting the new work. While these common practices were in development and still relevant in Snow’s time, his results would be difficult to reproduce due to the nature of cholera. Additionally, the predominant theory of how disease spread operated in the 20th century was not one based in germ theory, as that concept was yet to be developed. The leading theory was that of miasma, which is the idea that cholera was transferred via airborne poisonous vapors from foul smells due to poor sanitation. This theory, known as the “Great Stink” at the time, was largely agreed upon within the medical community, which provided great difficulty for Snow’s new germ based theory to take hold. (Tulchinsky, 2018). When medical experts finally began to understand the validity behind Snow’s claims, the process towards reducing mortality by means of disinfection became prominent towards the late 19th century. Along with filtration, the use of chlorine in water became a standard treatment for water disinfection. By the 20th century, deaths caused by waterborne diseases plummeted, especially in larger cities. Much of this improvement can ultimately be traced back to the research that John Snow had put into waterborne diseases such as cholera that played a major role in the germ theory.

A notable antagonist of Snow’s theory was parish priest Henry Whitehead. Whitehead was a native of Ramsgate and grew up in a heavily religious and academically oriented household. He was able to attend Lincoln College at Oxford University and became a highly educated man, proficient in data collection, poetry, and music (S.W.B. Newsom, 2006). Attached to St. Luke’s Church on Berwick Street in the Soho district, Whitehead was a well known and respected member of the community, and was a present for much of the cholera outbreaks during the 1850s. Following the main outbreak in the summer of 1854, the Board of Governors for the Soho district were initially skeptical of the theory Snow presented, and through investigations of the pump itself and discussion among their committee, Whitehead was given the chance to disprove Snow’s ideas. Though he was initially called upon in the early investigations of the epidemic, he offered to complete his own survey in an effort to put to rest Snow’s conclusions surrounding the Broad Street epidemic. However, Whitehead over the course of three months of his investigations would actually reinforce Snow’s findings, rather than debase them. Whitehead investigated deaths from various nearby streets that had access to the broad street pump and other larger community houses, along with testing theories related to cleanliness and fear-related deaths from cholera. Whitehead’s investigations confirmed much of what Snow had originally found, in that the primary source of the spread was seemingly access to the broad street pump, rather than some other origin or miasma based source. In fact, he noted that 58% of those who drank from the pump developed cholera while only  7% of the district population did without the broadstreet water (S.W.B. Newsom, 2006).

Finally, a later investigation into the pump revealed that a cesspit with poor engineering was leaking contents into the soil surrounding the pump. It is highly probable that fecal remains of an early patient with the contagion were disposed of into the cesspit, which then would contaminate the water supply for the hundreds of people who utilized the Broad Street pump.

Whitehead’s actions along with the thoughts of many others in the medical community during the 19th century were largely against the theories of John Snow. Despite the highly correlated data between those drinking the pump water on broad street and the spread of cholera, along with his investigations into Southwark & Vauxhall water company, many were hard pressed to abandon the long standing ideas of miasmatic spread of disease. Science is often a highly contested area of modern society, in which new and controversial ideas are heavily scrutinized and need an immense amount of data, study, and analysis to be accepted on a large scale. John Snow’s work and contribution to the understanding of cholera, disease spread, and ultimately epidemiology is symbolic of the larger challenge of new innovations and ideas. Though his theory was revolutionary, and stood to save hundreds if not thousands of lives, there still had to be lots of time and careful analysis of his work, along with the work of many others to fully make meaningful and lasting change. Snow’s and Whitehead’s interactions represent how science operates in society today. Without the doubt and criticism of Whitehead, it is likely that Snow’s theory would have been lost to history and it would have taken even more time for the miasma theory of disease spread to finally be ousted. Understanding the fact that the scientific process is not only slow, but challenging, competitive, and heavily scrutinized gives a greater appreciation for the amazing advancements our species has made. Without the countless hours of hard work, setbacks, and collaboration of researchers, scientists, and everyday people like John Snow, we would not be where we are today, standing on their shoulders.

Conclusion

Throughout history disease has ravaged communities as small as villages up to major cities. It has always taken a group humanitarian effort to confront and eliminate these illnesses that we are collectively forced to face. Among these, cholera has proved to be one of the most fatal of all times. Easily transferred with a dangerously high mortality rate, cholera quickly became a deadly threat to human tranquility. Medical experts from all around the globe worked tirelessly to find a solution to this threat. However, the prior theories and knowledge that were used to back their research only led to inaccurate hypotheses regarding the spread of cholera. It wasn’t until the research of John Snow that the truth finally began to be discovered. Even at that point, it would take countless more years and medical studies before Snow’s research would gain ground in the medical community. All of this however was worth the effort, as Snow’s discovery of waterborne diseases led to the worldwide effort to improve water sanitation which ultimately decreased the risk of cholera and other waterborne diseases for much of the world.

Bibliography & Citations

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• Freriches, R. (n.d.). John Snow | british physician & epidemiologist | Britannica. Britannica Encyclopedia. https://www.britannica.com/biography/John-Snow-British-physician

  https://www.britannica.com/biography/John-Snow-British-physician

• Holzman, R. (2021). John Snow: Anesthesiologist, Epidemiologist, Scientist, and Hero. National Center for Biotechnology Information. https://pubmed.ncbi.nlm.nih.gov/33913916/  doi: 10.1213/ANE.0000000000005586. PMID: 33913916.
• Williams, R. (n.d.). Robin’s Blog. Robins Blog. https://blog.rtwilson.com/john-snows-cholera-data-in-more-formats/comment-page-1/#comments
• Newsom, S. W. B. (2006). Pioneers in infection control: John Snow, Henry Whitehead, the Broad Street pump, and the beginnings of geographical epidemiology. National Center for Biotechnology Information. https://pubmed.ncbi.nlm.nih.gov/16891036/ www.sciencedirect.com/science/article/abs/pii/S0195670106002830.

• Tulchinsky, T. H. (2018a). John Snow, cholera, the Broad Street pump; Waterborne Diseases then and now. Case Studies in Public Health. https://pmc.ncbi.nlm.nih.gov/articles/PMC7150208/

Ai Use Disclosure

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• https://copilot.microsoft.com/
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