Drawing of the 1918 Influenza: Lymph sinus, some of the cells shown in their protoplasm - small clean spaces containing two, three or four fine deep brown spherules - shadows of colon bacilli. Credit: Wellcome Collection. Attribution 4.0 International (CC BY 4.0)

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Germ Theory of Putrefaction. Credit: Wellcome Collection. Attribution 4.0 International (CC BY 4.0)

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Credit: Bacilli of typhoid fever from a culture. Credit: Wellcome Collection. Attribution 4.0 International (CC BY 4.0)

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The Smallpox Hospital, St Pancras, London. Engraving. Credit: Wellcome Collection. Attribution 4.0 International (CC BY 4.0)

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A map taken from a report by Dr. John Snow. Credit: Wellcome Collection. Attribution 4.0 International (CC BY 4.0)

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First report of the committee of management of the Stockwell Fever and Smallpox Hospitals, 1871-2.

https://wellcomecollection.org/works/ugpzpx55

The Smallpox Hospital, St Pancras, London: with a wide expanse of grass in the foreground. Engraving. Credit: Wellcome Collection. Attribution 4.0 International (CC BY 4.0)