This is the first of a series of posts telling the story of Dr John Snow, a pioneer anaesthetist and epidemiologist.

After a brief biographical sketch, we shall follow Snow in his investigation of the mode of transmission of cholera in Victorian London, his premature death and the near oblivion to which his work was consigned for over 50 years, and its eventual rediscovery and re-publication by the American epidemiologist Wade Hampton Frost. 

We will follow the evolution of the cholera pandemics of 1848-49 and 1854 and give some health-political background to the events surrounding them.

This series is designed as an instructional course with a series of 18 posts (numbered 2 to 19) structured into Snow’s seven lessons:

• Snow’s review of what was known of the outbreaks and the main theories of communication of cholera prevalent in Snow’s time

• Snow’s theory

• Evidence for a propagated source of the epidemic

• Evidence for a point source of the epidemic

• Snow’s assessment of alternative explanations for the origins and mode of communication 

• Snow’s 12 principles for the prevention of cholera

• Aftermath

• A note on the two official investigations into the 1854 cholera outbreak around Golden Square, London.

• The amazing Reverend Whitehead

2. Reading materials for critical analysis and reflection in your own time. We have sourced open-access materials that go along with the 18 posts. 

Apart from this introductory biography, each post is divided into two parts. The first relates the story of cholera and Snow’s work. The second applies his method and thinking to contemporary events, specifically the SARS-CoV-2 pandemic. 

So, what motivates us to want to learn more about something?

We don't fully understand some issues, and we’d like your help dissecting the evidence and building an iterative understanding of Snow’s theories and their relationship to current thinking.

All lectures were accessible to paying subscribers, but we now make this series free as an educational course.   

We hope you will recognise our efforts by donating to TTE or becoming a paying subscriber, as writing the series took a lot of time and effort.

We have tried to let Snow tell his story with photographic excerpts from his main work: On the mode of communication of cholera. 2nd edition, much enlarged. London, J. Churchill, 1855, 162 pp. This is abbreviated as MCC2.

John Snow (1813-1858)

John Snow was born in York, Northern England, 1813, the son of a labourer who seemed to have become a landowner later in life. Snow was apprenticed to a Mr Hardcastle in the Newcastle-upon-Tyne area. Mr Hardcastle was a surgeon-apothecary, the lowest rung of the medical training ladder at the time. Apothecaries could issue prescriptions and make their own recipes from which they earned a living.

During his time in Newcastle, Snow witnessed the effects of the 1833 Asiatic cholera pandemic, and presumably, his lifelong interest in the disease started here.

Cholera was then one of the infectious diseases which periodically swept through Europe. It was thought to have originated in Asia, as all contagious diseases, especially the nasty ones, never originate in your own country. They always come from somewhere else.

The cause of cholera and its mode of communication were then unknown. Still, they were thought to be caused by miasma, a Greek word used to indicate noxious vapours originating from rotting organic matter, sewage, and rubbish left lying in unswept streets and accumulated in homes. 

Snow, at some time, decided to finish his training in London. Too poor to go by coach or train, he walked to London via Liverpool and enrolled in the Hunterian School of Medicine. He eventually finished his training and obtained his medical doctorate.

As an apprentice to Hardcastle, he could not drink, gamble, or marry. He was abstemious, drinking only water (distilled whenever possible), a vegetarian, did not smoke and was a very hard worker and debater in medical fora. Although extremely courteous in his dealings with everyone, Snow was not exactly the life and soul of the party, although in later life, he drank a little wine. He displayed a determined character and a propensity for lateral thinking.

Snow’s interest in newly discovered chloroform led him to study its mode of action and kinetics together with ether. He understood that the agent's blood concentration was related to the anaesthesia, pain relief, and consciousness level. He described five levels of anaesthesia (or “narcosis”) that corresponded to blood concentration. He also designed his own anaesthetic machines but never patented them.

As a pioneer anaesthetist, he became so famous that he was called to assist Queen Victoria in two of her labours.

Letter from Queen Victoria mentioning chloroform use in childbirth

He also opened a general medical practice from his lodgings in Bateman Street and then moved to Sackville Street, but this was less successful than his anaesthetic practice. It was said at the time that the rich and powerful had no problems letting Snow anaesthetise them but not treat them.

This probably reflected the upper-class attitude prevalent at the time.

In June 1858, Snow was found by his servant lying on the floor of his study, having suffered “apoplexy” and died a few days after that. He had been working on an anaesthesia treatise.