Victorian London was a filthy place. There were too many people living too close together without the infrastructure we consider necessary for modern life: electric lights, clean water, sewage service, garbage removal, refrigeration, etc. People died left and right from all kinds of communicable diseases. But they didn’t understand those diseases. The prevailing theory of infectious disease was the “miasma” theory -that foul smells spread diseases.
The true cause of disease—germs, or pathogens—wasn’t verified until Louis Pasteur conducted his experiments of the 1860s (though some scientists had proposed the idea much earlier), and it was another decade before the bacteria that cause tuberculosis, cholera, dysentery, leprosy, diphtheria, and other illnesses were identified and understood.
The Victorians made the classic error that correlation equals causation. Slums smell, due to poor sanitation, piles of garbage stacking up, and the lack of bathing and clothes-washing facilities; people in slums die of epidemics at a faster rate; ergo, stench causes disease.
And boy, did London stink.
The list of reasons why the city smelled so bad is not pleasant, but it led to efforts in cleaning it up. Which was the best thing they could have done at the time as far as stopping disease goes, even if they didn't understand why. Read the entire story at mental_floss.
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