Léon Charles Albert Calmette (July 12, 1863 - October 29, 1933) was a French physician, bacteriologist and immunologist, and an important officer of the Pasteur Institute. Calmette's main scientific work, which was to bring him worldwide fame and his name permanently attached to the history of medicine was the attempt to develop a vaccine against tuberculosis, which, at the time, was a major cause of death. Calmette worked with Jean-Marie Camille Guérin discovering how to culture the tuberculosis bacillus, Mycobacterium tuberculosis to create BCG or the Bacillus Calmette-Guérin vaccine against tuberculosis. No photographer credited, undated (cropped and cleaned).