In 1906-08 he worked in the French Congo, where he studied the transmission of trypanosomiasis and the role of tsetse flies.
In 1909-12 he took part in a mission in Senegal, Casamance and Dahomey, where he performed research of animal trypanosomiasis.
On this mission he conducted geographical distribution studies of nine tsetse fly species.
[1] In 1920, he and Félix Mesnil achieved the first experimental infection of chimpanzees with Plasmodium vivax.
[1] He was president of the Société entomologique de France in 1927 and a member of the French Academy of Sciences in 1938.