Miasma theory
Miasma theory is a key motif in this text and is the medical theory that diseases were caused by "bad air" called miasma.
Contagion theory
After the miasma theory, contagion theory was more widely believed and explained how cholera spread from person to person. The idea that disease spread from person to person was a revolutionary idea and changed the way society responded to diseases and outbreaks.
John Snow
John Snow symbolizes a typical rags-to-riches story. He started out from a working-class background but became one of the leading figures in the medical world.
London
In this text, London is used as a symbol for how a lack of public hygiene and healthcare can lead to a devastating spread of disease and ill-health. The city is depicted as being dirty, unhygienic, and overpopulated, making it the perfect breeding place for disease.
Cholera
The cholera epidemic of the 1800s is depicted as a symbol of how devastating epidemics could be for a society. This being said, cholera also symbolized the need for change in society and social hygiene, and medical developments.