Léon Charles Albert Calmette ForMemRS (12 July 1863 – 29 October 1933) was a French physician, bacteriologist and immunologist, and an important officer of the Pasteur Institute. He discovered the Bacillus Calmette-Guérin, an attenuated form of Mycobacterium bovis used in the BCG vaccine against tuberculosis. He also developed the first antivenom for snake venom, the Calmette's serum. Early career Calmette was born in Nice, France. He wanted to serve in the Navy and be a physician, so in 1881 he joined the School of Naval Physicians at Brest. He started to serve in 1883 in the Naval Medical Corps in Hong Kong, where he worked with Dr Patrick Manson, who studied the mosquito transmission of the parasitic worm, filaria, the cause of elephantiasis. Calmette completed his medical degree on the subject of filariasis. He was then assigned to Saint-Pierre and Miquelon, where he arrived in 1887. Afterwards, he served in West Africa, in Gabon and French Congo, where he researched malaria, sleeping sickness and pellagra. Association with Pasteur Upon his return to France in 1890, Calmette met Louis Pasteur (1822–1895) and Emile Roux (1853–1933), who was his professor in a course on bacteriology. He became an associate and was charged by Pasteur to found and direct a branch of the Pasteur Institute at Saigon (French Indochina), in 1891. There, he dedicated himself to the nascent field of toxicology, which had important connections to immunology, and he studied snake and bee venom, plant poisons and curare. He also organized the production of vaccines against smallpox and rabies and carried out research on cholera, and the fermentation of opium and rice. In 1894, he came back to France again and develop the first antivenoms for snake bites using immune sera from vaccinated horses (Calmette's serum). Work in this field was later taken up by Brazilian physician Vital Brazil, in São Paulo at the Instituto Butantan, who developed several other antivenoms against snakes, scorpions and spiders. He also took part in the development in the first immune serum against the bubonic plague (black pest), in collaboration with the discoverer of its pathogenic agent, Yersinia pestis, by Alexandre Yersin (1863–1943), and went to Portugal to study and to help fight a plague epidemic at Oporto in 1899. Institute leadership In 1895, Roux entrusted him with the directorship of the Institute's branch at Lille (Institut Pasteur de Lille), where he was to remain for the