Born about 1862 he was educated at University College, London where he served as assistant demonstrator of anatomy. He was house physician at the Great Northern Hospital and, becoming interested in diseases of the eye, was house surgeon at the Moorfields Eye Hospital 1889-91, and became surgeon to the Royal Westminster Ophthalmic Hospital, the Sick Children's Hospital in Great Ormond Street, and the Seamen's Hospital at Greenwich in 1895. He also served as demonstrator of anatomy and curator of the museum at Westminster Hospital. He retired from practice in 1902 and, his health failing, he went to South Africa, where he acted as locum tenens for Dr D J Wood of Cape Town during the winter of 1905-06. During the war of 1914-18 he was a temporary surgeon in the Royal Navy, and the rest of his life appears to have been spent in travelling. He died unmarried at the Royal Aero Club in Piccadilly on 14 March 1939. He left bequests of money to the Natural History Museum, the Victoria and Albert Museum, the Royal Society of Arts, and the National Rifle Association. Gunn is described as a quiet and rather taciturn man, who would have made a name for himself in ophthalmic surgery but for failure of health. Like his friend Charles Stoneham, FRCS he was much interested in ornithology. Publication:- Injuries and disease of the eye, in *Catalogue of the Westminster Hospital Museum* 1899.