Duclaux worked as an assistant to Pasteur for a few years, later returning as a senior collaborator before succeeding him as director of the Pasteur Institute, with Roux and Chamberland as close colleagues. He worked closely with Pasteur on sikworm disease and the fermentation of beer, and joined him in the debate about spontaneous generation. While based outside the Pasteur Institute (he held a succession of academic appointments), he remained a close associate of Pasteur’s. Perrin was a correspondent, and a fellow-leader of the defenders of Captain Dreyfus in a notorious case of institutional anti-semitism.
Hooker and Tyndall were close lifelong friends, met during Huxley’s twenties as a rising scientific star. Hooker and Huxley later became Darwin’s strongest and most trusted supporters (Darwin’s strongest advocates abroad, Haeckel and Gray, were also linked to Huxley: Haeckel and he were mutual admirers and lively correspondents, while Gray met him on a visit to England). Owen was an antagonistic rival (probably the two greatest anatomists of their time, Huxley emerging a clear winner). Wells was a protégé. Helmholtz was a guest at Huxley’s scientific dining club: Tyndall, Frankland, Spencer and Hooker were all regular members.
Girard studied with Agassiz in Switzerland and accompanied him to the U.S. Baird invited him to work on the Smithsonian’s reptile and fish collection.