A young doctor, freshly arrived, hastened to meet him: Georges Duhamel. With the help of Paul Santy, Leriche undertook very extensive research work on osteogenesis and was particularly interested in repairing fractures with experiments carried out on rabbits, and he was already pursuing scholarly reflections on the role of vasa motricity in the site of trauma. That required many cuts histological and as many X-rays or photographs, but the environment and the organization of the very large 3,000-bed field hospital permitted it. He became chief surgeon on 28 December 1917.