Born at Blackburn on 21 January 1866, the second child and eldest son of Thomas Firth, cotton spinner and manufacturer, and Betty Fielden Lacy, his wife. He was educated privately and at Owens College, Manchester, before beginning his medical training at King's College and University College Hospital Medical Schools in London. He won an exhibition and the gold medal in physiology and histology at the intermediate MB, and took honours in anatomy, materia medica, and obstetrics at the first MB examination in 1886. He served as house surgeon at the Royal Infirmary, Bradford, at the Royal Berkshire Hospital, Reading, and at the General Hospital, Bristol, where he then settled in practice. He was connected with the General Hospital, a branch of the Royal Hospital, for forty-seven years, being appointed house surgeon 1893, assistant surgeon 1896, surgeon to the throat, ear, and nose department, full surgeon 1902, and consulting surgeon on his retirement in 1926. During the war of 1914-18 he served at the 2nd Southern General Hospital at Bristol, having been commissioned captain *à la suite* at the formation of the RAMC territorial force 30 September 1908. He was a Fellow of the Association of Surgeons, and president of the Bristol Medico-chirurgical Society in 1923-24; he had been a rapporteur of its meetings from 1901 to 1913, and for many years editor of the reviews in the society's *Journal*. Lacy Firth married on 12 March 1908 Winifred Mary, daughter of Lewis Edmund Naish, of Bristol, and widow of Henry Ernest Grace, also of Bristol. He died suddenly at his house, 8 Victoria Square, Clifton, Bristol, on 26 April 1943. Mrs Firth survived him; there were no children. Publications:- Torsion of the spermatic cord. *Bristol med chir J*. 1904, 22, 320. On nephropexy. *Ibid*. 1913, 31, 220. The evolutionary history of renal surgery and of temporal bone (Presidential address). *Ibid*. 1924, 41, 1 and 49.