John Snow

English physician

• Born: March 15, 1813
• Place of Birth: York, England
• Died: June 16, 1858
• Place of Death: London, England

Significance: As the first epidemiologist, John Snow made several contributions to public health. He traced the origin of a significant cholera outbreak in 1854 and identified ways to improve the handling of sewage and water to reduce future outbreaks. Snow was also an early proponent of using anesthesia and practicing good hygiene during medical procedures.

Educated: Hunterian School of Medicine; University of London

Background

John Snow was born in York, England, on March 15, 1813. He was the oldest of eight children born to William and Frances Snow. His father was an unskilled worker in coalmines and in agriculture, and they lived in a poor neighborhood. The family was religious; Snow and his siblings were baptized at All Saint's Anglican Church on North Street in York.

The church may have played a role in Snow's early education; most common day schools of the time were private schools, but places in them were arranged for members of local church congregations. Still, his family would have had to pay for his education. His father became a driver of horse-drawn vehicles and delivered goods throughout the warehouses in York. He eventually bought several houses, which he rented out for additional income. The family accomplished an upward financial climb that was rare in nineteenth-century England.

As a result, Snow, who was a good student, got a better education than many poor children of the time. He was especially interested in natural history and mathematics. He also took advantage of several apprenticeships beginning when he was fourteen years old. Snow first apprenticed in the town of Newcastle-upon-Tyne with William Hardcastle, beginning on June 22, 1827. Hardcastle was a surgeon-apothecary, which was the nineteenth-century equivalent of a general practice doctor. Snow's apprenticeship was many miles from his York home and was likely arranged with the assistance of his wealthy uncle Charles Empson. This apprenticeship continued for six years, until Snow was twenty.

Snow was only eighteen years old and in the midst of his first apprenticeship when his experience with a cholera epidemic set him on a course he would pursue the rest of his life. Hardcastle sent Snow to help miners afflicted with cholera, a disease characterized by abdominal pain, severe diarrhea, and dehydration, in a nearby town in 1831. This was the first known epidemic of the condition in Great Britain, and it left a lasting impression on the future physician; he would later develop a dedication to finding ways to prevent the suffering that came with the disease.

After completing his apprenticeship with Hardcastle, Snow apprenticed with two apothecaries from 1833 to 1836. He was twenty-three when he entered Hunterian School of Medicine in October 1836. He continued his formal education at the University of London, from which he graduated as a medical doctor on December 20, 1844.

Life's Work

Snow opened his own practice in the town of Soho. During his training, he had become interested in why newborns sometimes suffered asphyxia, or a lack of oxygen, or even death caused by choking. This led him to study breathing and the respiratory system. He made presentations to the Westminster Medical Society in 1841 before he finished his formal studies and became known for his interest in the subject. As a result, he was asked to be present in December 1846 when ether was administered for one of the first times ever in England. Within a month, he created tables to help physicians understand how much ether to use based on the temperature of the room. Snow soon became the foremost authority on the use of anesthesia in the United Kingdom and was called upon to administer chloroform to assist Queen Victoria during the births of her son, Leopold, and daughter, Beatrice.

This interest in breathing and the human respiratory system was also a key factor in Snow's major medical innovations related to communicable diseases. In 1848, just a few years after Snow finished his formal medical training, a cholera epidemic raged through London. At the time, physicians did not yet know that sickness was caused by organisms such as germs and viruses. Many thought cholera was caused by miasma, or bad air. In 1849, Snow published On the Mode of Communication of Cholera, in which he proposed that the disease was caused by something in the fluids released by a person who had the disease and spread through unintentional contact with water that was contaminated by these fluids.

An additional outbreak in 1853 provided Snow with an opportunity to test his theory. He began a study comparing the number of cases of cholera from water that was contaminated with sewage versus water from the Thames River that was not contaminated. In August 1854, when more than 550 people died of cholera in two weeks' time in a small area near his Soho office, Snow conducted door-to-door interviews and created a map of households affected by the disease that led him to believe that a single water pump was responsible for the epidemic. He convinced officials to close the pump, and the disease faded. Despite Snow's findings, it would not be for another ten years that his germ theory of disease transmission would be widely accepted.

Impact

Snow's innovative approach to the prevention of cholera made him a pioneer in the study of epidemiology, or the spread of diseases. It also led to the identification of the organism Vibrio cholerae, which is now known to be the cause of cholera. He would go on to pressure government officials to establish sanitary water and sewage disposal systems that further curtailed the spread of disease and improved public health in the United Kingdom. As other countries adopted similar practices, the influence of Snow's work spread throughout the world. His career-long interest in anesthesia led to the establishment of using the practice as a routine part of medical and dental surgery.

Personal

Snow never married and is not known to have had any children. He had a stroke and died on June 16, 1858, at forty-five years old. He is buried in Brompton Cemetery, which is owned by the British Crown and is one of the Magnificent Seven cemeteries in London.

Bibliography

Avdulla, Christos S., and Ntaniela Tachirai. "John Snow: The Pioneer of Modern Epidemiology and Anesthesia." Cureus, vol. 16, no. 8, 2024, doi: 10.7759/cureus.67602. Accessed 4 Oct. 2024.

"Biography of John Snow." University of California-Los Angeles Department of Epidemiology Fielding School of Public Health, www.ph.ucla.edu/epi/snow/snowbio.html. Accessed 4 Oct. 2024.

"Cholera: Symptoms." Mayo Clinic, www.mayoclinic.org/diseases-conditions/cholera/basics/symptoms/con-20031469. Accessed 4 Oct. 2024.

Fine, Paul, et al. "John Snow's Legacy: Epidemiology without Borders." Lancet, 13 Apr. 2013, vol. 381, no. 9874, pp. 1302–1311.

"John Snow (1831–1858)." BBC, www.bbc.co.uk/history/historic‗figures/snow‗john.shtml. Accessed 4 Oct. 2024.

"John Snow (1818–1858)." John Snow Bicentenary, London School of Hygiene & Tropical Medicine, johnsnowbicentenary.lshtm.ac.uk/about-john-snow/. Accessed 4 Oct. 2024.

"John Snow – The Father of Epidemiology." Boston University School of Public Health, 1 Oct. 2015, sphweb.bumc.bu.edu/otlt/MPH-Modules/PH/PublicHealthHistory/publichealthhistory6.html. Accessed 4 Oct. 2024.

Kukaswadia, Atif. "John Snow – The First Epidemiologist." PLOS.org, 11 Mar. 2013, blogs.plos.org/publichealth/2013/03/11/john-snow-the-first-epidemiologist/. Accessed 4 Oct. 2024.