Label 'Chloride of Lime', paper, 1876–1900. Museum of London.
Owing to the prevailing miasma theory that proposed cholera was transmitted by polluted air, chloride of lime – similar to commercial bleach – was used as a disinfectant to purify the air and prevent infection. As it was used in vast quantities it may have polluted, rather than purified, the air. It is still used in epidemics, probably to little effect.