John Bertram Gilchrist Muir was born on 18 July 1899 at Kai Yuan, Manchuria, where his father, who had qualified in Edinburgh, was a medical missionary. He was educated at George Watson's College, Edinburgh, Eltham College in London and the Middlesex Hospital. His medical training was interrupted by service with the 52nd Royal Fusiliers in 1917-1918 where he reached the rank of Lance-Corporal. On returning to the Middlesex Hospital he took prizes in anatomy, physiology, medicine and surgery and qualified with the Conjoint Diploma in 1921 and MB BS London 1923. He was house surgeon to Gordon Gordon-Taylor and surgical registrar to Sampson Handley. He took the FRCS in 1924. On leaving the Middlesex Hospital, having recently married, he returned to China, as he could not afford the long wait to set up practice in London. At first he was in surgical practice in Shanghai (1924-26) but later accepted a position at the Kailan Mines in North China, becoming their principal medical officer and chief surgeon (1929-1941). During this period he took every opportunity during his leaves, which came every three years, to visit the surgical clinics of North America, and in 1937 returned to London long enough to sit the MS and win the Gold Medal in 1937. In 1941 he left for Tasmania, becoming surgeon superintendent at the Royal Hobart Hospital. His younger brother, Sir Edward Muir, became PRCS. He married in 1924 and of his two sons the elder, David Muir (FRCS, FRACS) has followed in his father's footsteps, the younger, Malcolm, contracted poliomyelitis. His first wife died soon after his move to Tasmania, but when he died on 13 January 1975 he was survived by his second wife, Joan.