Bellingham, O'Bryen (1805–57), doctor, was born 12 December 1805 in Castlebellingham, Co. Louth, third son and fourth child among five sons and three daughters of Sir Alan Bellingham (1776–1827), 2nd baronet, and Elizabeth Bellingham (née Walls). He was educated at the Feinaiglian Institution, Dublin. Apprenticed (1822) to James Duggan in Dublin, he studied at Jervis Street Hospital, the RCSI (LRCSI 1828), and Edinburgh University (MD 1830). Elected (1833) a member of the RCSI, he subsequently became a member of its pharmacy court of examiners, professor of botany (1842–50), examiner in surgery (1850), hon. librarian (1854–7), and chairman of the court of examiners (1856). He lectured on materia medica in various medical schools, including that of Robert Adams (qv), to whom he rented his coach house and stables for his new school in Eccles St. Although a protestant, he was appointed visiting surgeon to St Vincent's Hospital, Dublin (1835–57), on the recommendation of the catholic archbishop Daniel Murray (qv).
His original clinical observations were numerous and he published articles on a variety of subjects including dermatology and ophthalmology. During the famine he correctly attributed the outbreak of scurvy to dietary deficiency caused by lack of potatoes (Dublin Medical Press, xviii (1847), 34–8). His reputation is founded on his cure for aneurysm: he published Observations on aneurysm and its treatment by compression (1847) and A treatise on diseases of the heart (1857), described as a ‘Victorian masterpiece of cardiology’ (Eoin O'Brien et al., 122). He was secretary to the Surgical Society of Ireland.
A keen naturalist from boyhood, he was a founder member of the Natural History Society (1838) and of the Proceedings of the Dublin Natural History Society (1849). In the Magazine of Natural History (1840) and the Annals of Natural History (1844), he published a ‘Catalogue of the entozoa indigenous to Ireland’ which became a valuable source of reference and involved the dissection of 270 mammals, 360 birds, and 380 fishes; a skilled dissector and taxidermist, he presented his specimens to the museum of the RCSI. He died 11 October 1857 at Castlebellingham, where he was buried in the family tomb. In 1858 the council of the RCSI commissioned J. R. Kirk (qv) to sculpt a bust of Bellingham, which is preserved in the college, and St Vincent's Hospital instituted the annual memorial Bellingham gold medal in medicine. He married Matilda Molloy (d. 1883); no evidence of children has been found.