Robert Koch identified the bacteria that cause tuberculosis, cholera, and anthrax — discoveries that saved more lives than any single physician in history. But his ambition drove him to announce a tuberculosis cure before it was proven, and the tuberculin disaster that followed killed patients, destroyed his reputation, and revealed that the line between scientific genius and dangerous overconfidence can be fatally thin.

This episode traces Koch from his country medical practice through the anthrax and tuberculosis breakthroughs, the Nobel Prize, the tuberculin scandal, and the rivalry with Pasteur that defined nineteenth-century bacteriology.

• Koch’s isolation of the anthrax bacillus and the postulates that established germ theory as law
• The tuberculosis discovery — identifying the bacterium behind the nineteenth century’s deadliest disease
• The tuberculin disaster — the premature cure announcement that killed patients and ruined careers
• The Koch-Pasteur rivalry and Koch’s lasting impact on medicine despite the scandal