Louis Pasteur and Dom Pedro II engaged in rabies vaccine development.

Louis Pasteur is the renowned chemist and microbiologist of the 19th century involved in the development of the rabies vaccine. He worked with a researchers team in the laboratory, mainly Pierre Paul Emile Roux, and also physicians in the clinical practice approach and the defense of Pasteur's anti-rabies technique in the Académie Nationale de Médecine, Alfred Vulpian being the most notable. Pasteur's first studies on rabies are noted in his 1881 publication. But in 1885, he revealed that he had already immunized 50 dogs against rabies. Meanwhile, he was looking for human subjects. The most polemic of this search involves the second and last Emperor of Brazil, Dom Pedro II, who was a patron of the arts and sciences and followed and supported the work of the great scientist. During the reign of Dom Pedro II, the first Pasteur's Institute was founded in Rio de Janeiro, nine months before the Parisian, which had the financial support of Dom Pedro. This article deals with the interaction between the two outstanding characters, especially in the development of prophylactic treatment against rabies, and with the utilitarian aspects of this vaccine researches development against individual autonomy.