Today in History is a daily newsletter from Britannica. (more) Today in History—March 24: The Lecture That Unraveled the Mystery of Tuberculosis Written by Michele Metych Michele Metych is the lead editor for Today in History at Encyclopædia Britannica. Michele Metych Fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors Last updated Mar. 20, 2026 •History On this day in 1882, German physician Robert Koch gave a lecture at the monthly meeting of the Berlin Physiological Society announcing that he had discovered the cause of tuberculosis: the tuberculosis bacterium. Today in History is a daily newsletter from Britannica.Encyclopædia Britannica, Inc. That sounds like a well, duh, now. But that night, the shy, usually hesitant man spoke clearly as he turned medicine, microbiology, and public health on their heads. He’d isolated it...

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