Was educated at Westminster Hospital, where he was in succession House Physician, House Surgeon, and Resident Obstetric Assistant. After taking a voyage to South America as Surgeon to a Royal Mail Steam Packet, he took a high place in the entrance examination to the Royal Navy in 1898. He served on HMS* Powerful* at a China station, and adopting the opportunity, after five years' service, of practising surgery, he resigned his commission in 1903, acted as Resident Medical Officer to the Queen's Hospital for Children, Hackney, and in 1905 passed the FRCS examination. Upon this he was appointed in 1906 Surgical Registrar to Westminster Hospital and Assistant Surgeon to the Queen's Hospital. In 1908 he was elected Surgeon to the Bolingbroke Hospital, and shortly afterwards Assistant Surgeon to Westminster Hospital. He showed himself well fitted for the posts in skill and manner, and promised to become a surgeon of good standing. Subsequently he acted as Surgical Tutor, Demonstrator of Practical Surgery, and carried out a great deal of surgery, especi-ally in cases of emergency, at the two general hospitals with marked success. On a holiday at Ostend he was knocked down whilst crossing a street, sustaining a deep cut on the forehead and concussion with unconsciousness for at least a day. At the outbreak of the War Swainson was put in charge of the Scottish Red Cross Hospital at Dunkirk, and carried through most laborious surgical work in the midst of severe bombardment. He does not seem to have met with any head injury, nor was he otherwise wounded, but he was utterly shaken by the bombardment. He may have been damaged by the Ostend accident, for he broke down and became mentally incapacitated. After his return to England he got worse, until he lapsed into a state of mania, at times of the utmost violence requiring full control. He was granted leave of absence several times, and his sister finally sent in the resignation of his post at Westminster Hospital. After more than two years he gradually improved, and was employed for two years on a Medical Board of the Ministry of Pensions. Then with further improvement, although insufficient to allow of a return to surgical practice, he was able in 1921 to take up the post of Demonstrator of Anatomy at St Thomas's Hospital. His anatomical knowledge was both extensive and accurate, and he enlarged it by reading in comparative anatomy and embryology. Indeed, he was gaining success as a teacher. He died unmarried, after a day or so of illness, perhaps from influenza, on May 16th, 1923, at 21 Rims Road, Clapham Common.