Arthur Conan Doyle was an English physician (who would later write the famous Sherlock Holmes novels). After learning of Robert Koch’s supposed cure for tuberculosis, he became obsessed with meeting the scientist and learning more about the vaccine. Though he never met the doctor, he independently discovered that Koch’s vaccine was not an effective treatment or cure for TB. He did recognize, however, that it could be used as a diagnostic tool. His discovery led to the downfall of Koch’s reputation.