After qualifying as a physician, Rolleston became a Fellow of Pembroke College in 1851, holding posts at the British Civil Hospital,
Smyrna (during
Crimean War), and Assistant Physician,
Children's Hospital, London (1857). Gradually he became more interested in zoology, and spent the rest of his career as a zoologist, and on the human sciences. His research included
comparative anatomy,
physiology,
zoology,
archaeology and
anthropology. In 1860, he was elected to the newly founded Linacre Professorship of Anatomy and Physiology, which he held to the time of his death. He became
FRCP in 1859, was elected
Fellow of the
Royal Society on 5 June 1862, and Fellow of
Merton College, Oxford, in 1872. He was a member of the Council of the
Oxford University, its representative in the
General Medical Council, and also an active member of the Oxford Local Board. Rolleston was one of the organisers for the meeting: he arranged for Huxley to stay at Christ Church during the meeting, and to have a crocodile skull in Huxley's room for study. Huxley was instrumental in Rolleston's appointment to the Linacre chair that very year, backing him against Owen's candidate. Rolleston wrote him a 'you'll never regret this' letter. As an expert on the brain, Rolleston was present on the Thursday, when Huxley denied Owen's claim that the human brain had parts that apes did not, and again on the Saturday for the debate on Darwin, where his opponent was Bishop
Samuel Wilberforce. Rolleston was an
Anglican, but a liberal in his religious beliefs, as was Huxley's other supporter in the brain debate,
William Henry Flower. Huxley organised his FRS, as he did for Flower; and the two men acted as liaison between the
X-Club and the
Royal Society. Rolleston remarked later that whenever he lectured on evolution, he was asked 'Was I an
atheist or a
Unitarian?' and some of Huxley's attacks on the Old Testament did cause him anguish. Rolleston was so identified with Huxley at this time that he appeared as one of 'Tom Huxley's low set' in the ironical skit
Report of a sad case recently tried before the Lord Mayor, Owen versus Huxley (publ. George Pycraft 1863) as 'Charlie Darwin the pigeon-fancier and Rollstone' cheer on their barrow-boy. This vivid broadsheet was certainly well informed: it mentions Owen's disgraceful maltreatment of
Gideon Mantell. He was elected as a member of the
American Philosophical Society in 1869. == Personal life ==