[The itenerary of a sage].

Paul-Louis Simond was born on 30 July 1858 in the Drôme region of France and completed his medical degree in Bordeaux, having sojourned in Guyana. His professional career led him to serve in the military by representing the Paris Pasteur Institute in the Far East, Brazil, and Turkey. He was one of the founders of the Pharo School of Tropical Medicine in Marseille and he finished his career as head of the Health Service in Indochina. He died in 1947, in Valence, after a long period of retirement, which he devoted to social work in his hometown. His research covered numerous aspects of tropical pathology and public health. His studies of yellow fever and plague in particular were major landmarks. In 1898 he discovered and demonstrated the means of transmission of bubonic plague--a discovery which took time to be acknowledged and thus deprived him of the notoriety he deserved. By demonstrating the dependency of a human disease with regard to an onzooty, Simond opened the way to the concept of anthropozoonose and made a remarkable contribution to the epidemiological study of diseases transmitted by insects. P.L. Simond had an exceptionally rich personality. Besides being a rigorous Pasteurian, a military official endowed with important responsibilities, he was an enlightened amateur and a passionate naturalist. He was also a true humanist and his writings reveal a man loyal to his cause, a man of exceptional lucidity and rare serenity. Such qualities give him and his work a very special quality.