John Snow

John Snow was born in York, into one of it's poorest neigbourhoods, and began his career at age 14 when he started a medical apprenticeship in Newcastle. During his time there he encountered a cholera epidemic in Killingworth – a local coal mining village and he treated lots of the patients. Cholera can be a nasty infection and at the time no one really knew much about where diseases came from or how they spread. Lots of people thought diseases were spread by miasma, or ‘bad air’ – they didn’t know much about germs yet. ​

In the 1830s Snow worked at the Newcastle Infirmary with a surgeon called Thomas Greenhow and together they conducted research about a disease called cholera. ​In 1837, he moved to London and started work at Westminster Hospital. The following year he was admitted to the Royal College of Surgeons of England and studied at the University of London.

In the mid 1800s there were multiple cholera outbreaks. Snow created a map to plot out the cholera cases near Broad Street in London - each of the black rectangles represented a case. He created it to see if there was a pattern to how the disease spread. At this time people collected water from shared water pumps in the streets, John tried examining water samples from the one on Broad street using chemistry and looking at it through microscopes but couldn’t prove the pump was the cause, however his studies of the spread of the disease convinced the local council to remove the handle of the pump and this is credited as ending the outbreak. He wasn’t the first person to use a map to record the spread of cholera but was the first person to link the spread to contaminated water. ​Snow later used statistics to show the connection between contaminated water and cases of the cholera disease by comparing homes supplied with clean water and those getting water contaminated with sewage. This is considered to be the foundation of epidemiology – the study of diseases, their spread and causes. Snow was a founding member of the Epidemiological Society of London, formed as a response to a cholera outbreak in 1849.

In addition to his interest in the study of diseases, John Snow was also a pioneer in anesthesia. In 1843 he studied the effects of ether on respiration and wrote a guide for its use. He soon became the most accomplished anesthetist in Britain. He also experimented with chloroform and realised it was much more potent than ether. Its use had led to the deaths of patients so he published a letter to the Lancet (a medical journal) noting how it should be used carefully.

John Snow was one of the first physicians to calculate the dosage of anesthetic someone would need to reduce a patients pain and suffering during a procedure. This not only extended to surgery but also childbirth. He was able to work out the dosage needed (usually of chloroform) to relieve pain during childbirth without sending the mother to sleep and at her request, he provided this to Queen Victoria during the birth of two of her children.