sentences:  In collaboration with Georges-Fernand Widal (1862–1929), he studied the aetiology of the disease, and in 1888 developed an experimental antityphoid inoculation.Also with Widal, he isolated the bacillus that was the cause of dysentery, however the two scientists were unable to establish the aetiological link to the disease.From 1897 to 1903 he was a professor of comparative and experimental pathology in Paris, becoming a member of the Académie de Médecine in 1901.