Charles Nicolle was a Nobel Prize–winning French bacteriologist. Director of the Pasteur Institute of Tunis from 1903 until his death in 1936, he was founder and editor of the institute's Archives and prime mover of the (French-) Tunisian medical “cosmos” he had carefully orchestrated to revolve around that institute. He is best known for his 1909 demonstration of the louse transmission of typhus—research that helped earn him the Nobel. He also made significant contributions to the understanding of—among other diseases—relapsing fever, toxoplasmosis, trachoma, and kala-azar. On a level at once theoretical and practical, he constructed a type of acute, symptomless infection—“inapparent” infection—that informed his philosophical treatment of disease evolution and his pioneering theories of emergent diseases. France awarded him with its Osiris Prize, election as a nonresident member of the Académie des Sciences, and appointment to the Chair of Experimental Medicine at the Collège de France. In his spare time, he wrote seven novels and a number of short stories. Above all, however, Charles Nicolle was a microbiologist on a mission.

Nicolle's “mission” was defined and animated by his “Pastorian” identity. He himself described this identity: “In our country, we are often given the name Pastorians. It is not only a title of honor because it evokes one of the greatest human intellects, whose life exemplified discipline. It is also, on account of this discipline, a comparison with members of a religious order.” The Pastorians were “created” by Louis Pasteur's miraculous act: the salvation of a young boy who had been bitten by a rabid dog from otherwise certain and agonizing death, through the audacious application of his recently developed antirabies vaccine in 1885. Monetary contributions and infected pilgrims subsequently poured into Paris from around France and the globe, culminating in the opening of Pasteur's “institute” in 1888. His humble collaborators were elevated to the status of “disciples,” who served the “Master,” and trained new Pastorians, at the place they called the “Maison mère”: the “Mother House.”The Pastorian understanding of the microbial origins of infectious diseases blended with recent German work, giving force to a “germ theory” of disease that led the faithful to believe they were living in a revolutionary “Golden Age” of medicine.