In 1875, tuberculosis was the deadliest disease in the world, accountable for a third of all deaths. A diagnosis of TB—often called consumption—was a death sentence. Then, in a triumph of medical science, a German doctor named Robert Koch deployed an unprecedented scientific rigor to discover the bacteria that caused TB. Koch soon embarked on a remedy—a remedy that would be his undoing.   When Koch announced his cure for consumption, Arthur Conan Doyle, then a small-town doctor in England and sometime writer, went to Berlin to cover the event. Touring the ward of reportedly cured patients, he was horrified. Koch’s "remedy" was either sloppy science or outright fraud.   But to a world desperate for relief, Koch’s remedy wasn’t so easily dismissed. As Europe’s consumptives descended upon Berlin, Koch urgently tried to prove his case. Conan Doyle, meanwhile, returned to England determined to abandon medicine in favor of writing. In particular, he turned to a character inspired by the very scientific methods that Koch had formulated: Sherlock Holmes.   Capturing the moment when mystery and magic began to yield to science, The Remedy chronicles the stunning story of how the germ theory of disease became a true fact, how two men of ambition were emboldened to reach for something more, and how scientific discoveries evolve into social truths.