Snow was unable to study cholera first-hand after the end of the first cholera outbreak of 1832. It was not until 1849, when a second outbreak occurred, that he could study its trans again. In between these two outbreaks, Snow conducted research on respiration and anesthesiology which caused him to think that the miasma theory could not be true. He started his research on respiration while still at the Hunterian School of Medicine. This is when Snow studied the gas laws and applied this research to the newly formed branch of medicine, anesthesiology.
His extensive knowledge of respiration helped him to become an “original leader in the science of anesthesiology. ” Anesthesiology was first practiced in 1846. At this time, Snow researched Chloroform as an anesthetic agent. This research had perhaps allowed him to disprove the miasma theory by “systematically [considering] absorption, distribution, metabolism and excretion as central to understanding the activity of an external agent. ” This pioneering research gave him knowledge to disprove this theory (Goldstein, 2012).
Both his respiration research and prior knowledge of cholera in 1832 contributed to this research and led him to believe “cholera was attributable to a self-replicating agent which was excreted in the cholera evacuations and inadvertently ingested, often, but not necessarily, through the medium of water” (John ? Snow). Interestingly, Snow was not the only one who thought water was the mode of communication of cholera. He was not even the first to come up with this theory and publish it. In 1832, John Parkin had published a theory saying that the transmission of cholera was through water.
Then why is John Snow credited with this discovery? In 1832, John Parkin hypothesized that through “springs” cholera was transferred into humans by water. Where he was wrong, however, was that he thought that cholera was a poison which came from the earth. The source as “the earth” and is quite vague. This may have devalued his theory of water as the mode of transmission because it was so unbelievable and without evidence. Parkin said that the uptake of this poison through a fluid is what causes cholera.
Once entering the gastrointestinal tract, he believed that cholera is absorbed into the blood and acts on the blood, causing components of the blood to be released from the body (Parkin, 1883). Parkin was partially correct but never had enough evidence to prove the correct parts of his theory. It is unknown if Snow’s ideas were original or not. It is also unknown if Snow had read Parkin’s paper since Snow never acknowledged him in his writings but they had similar ideas. Snow’s idea of water as a source of communication was common.
Henle had the same idea as Snow and may have been the original person to come up with the idea. Even though there is a possiblility that Snow’s idea of cholera transmission by water was not original, Snow provided extensive research on the topic, more than any other researcher. Many of Snow’s colleagues give him credit for the idea including William Budd who also had the same idea but gives credit to Snow for his extensive work on it. Communication of cholera from person to person was also a common belief. Other researchers thought, as Snow did, that cholera was a microorganism of the intestines.
However, Snow did the most extensive research on it. He was able to prove that water was the mode of communication so he was given credit although he may not have been the original person to come up with the idea (Snow, J. , Richardson, B. , & Frost, W. , 1936). Several prior works are mentioned which Snow used to support his claim of water being the mode of communication. These works include: Albion Terrace research by Dr. Milroy in 1849, Rotherhithe research by Dr. Lloyd in 1849, Manchester reports in the “Report of the General Board of Health on the Cholera of 1848 and 1849,”
Ilford, Essex by Dr. Chambers in 1849, Newburn by Dr. Craigie in 1849, Cunnatore by Dr. Cruikshanks in 1853, and the Black Sea Fleet in 1854 by a medical officer. Many people were researching and trying to prove water as the means of communication of cholera (Snow, 1855). John Snow was able to prove it by conducting an extensive survey and by using other researcher’s work as support. It is unknown whether Snow received the idea from one of these authors, Parkin, someone else, or thought it up himself. John Snow’s study of cholera in 1849 was what John Parkin theorized many years before.
Even though Parkin had this idea well before Snow, Snow had performed a much more convincing study which supported water as the source of cholera. Snow also had the advantage of mapping the outbreak of cholera and finding its source, sewage. This is much more believable than Parkin’s theory that the disease was a poison from the earth (M. G. , 1937). Snow provided symptoms of Cholera, to disavow air as the means of transfer. He often saw symptoms start in the alimentary canal and not the lungs. This provided evidence for water or food as the means of transfer.
He continued to theorize new details about how cholera affected the human body throughout his research. In 1848, Snow believed cholera was “communicated by something that acts directly on the alimentary canal. ” Snow was convinced that cholera was transmitted by at least two means: by ingesting water contaminated in some way by a prior sufferer and by hand to mouth contact between family members (Vinten-Johansen, 2003). In 1849, he concluded that cholera was caused by the consumption of something due to the symptoms being vomiting and diarrhea.
This is evidence for the disease occurring in the alimentary canal. He believed the culprit was either food, water, or both. Although snow kept an open mind, he tried to disprove theories he knew were false. For example, Snow’s belief of miasmas was that there is no evidence for air as a means of how cholera is transferred so it should not be believed. Snow provides symptoms of Cholera, which he often saw start in the alimentary canal, to disavow air as the means of transfer. (Snow, 1855). He was confident in his beliefs and the reason he was confident was because of evidence.
Before his publication of his first edition of “On the Mode of Communication of Cholera” in 1849, John Grant published an article saying that miasmas were the cause of the cholera outbreak that year. After reading this, Snow knew he needed to publish “On the Mode of Communication of Cholera” as fast as he could. He first had to gain more evidence for his first attack on the miasma theory. His theory was that the broken sewer pipes were seeping water into the drinking water pipes. He examined not only the pipes, but also tanks and where the water and sewage drained into.
After observing the water and sewage system, the main source of contamination he found was the contaminated sewage water entering the drains of the drinking water. This contaminated the drinking water with Vibrio cholerae in 1849 London. Snow worked fast, publishing “On the Mode of Communication of Cholera” only weeks after John Grant published miasmas as the cause of the outbreak (VintenJohansen, 2003). John Snow was a Pyrrhonian skeptic, not taking well-accepted theories as a fact, but rather, always keeping his mind open to new ideas.
His work as a medical apprentice, early in his life, set the foundation for his theory of water as the means of cholera communication. He was able to disprove miasma through his work as an anesthesiologist and his study of the respiratory system. He had this knowledge by the time of the second and thirds outbreaks of cholera in 1849 and 1855. He was a great statistician and was able to provide enough evidence during the two outbreaks to prove his theory. Snow took the ideas of other scientists and applied it to his work.
For example, he studied Francis Bacon’s work and applied his concept of the experimentum cruces to his study. However, he was a pioneer, coming up with most of the structure of the structure of his experiments on his own. His work on cholera was a type of experiment no one had observed before. For his methods of research, Snow became the father of epidemiology. Snow did not let other’s theories influence him much when there was little evidence available. He believed his ideas and provided evidence for them. His qualities of open-mindedness to new ideas and skepticism allowed him to one of the greatest researchers in history.