The third son of Louis Thomas, a merchant whose place of business in George Street, Sheffield, was on the site now occupied by the Sheffield Banking Company. He was educated at a private school in Wakefield and was apprenticed to his brother-in-law, Thomas Waterhouse. He then studied in London and Paris, and settled in Sheffield about 1857, where he succeeded Thomas Waterhouse, and took the house in which he had practised. He was elected Surgeon to the Sheffield Infirmary on July 30th, 1835, on the retirement of W Staniforth, junr, and retired on account of illness in 1848, when he was appointed Consulting Surgeon. He was one of the founders of the Sheffield Scripture Readers' Society and took particular interest in this and kindred Societies. He was found dead in his lavatory at his residence, 260 Brook Hill, Sheffield, on August 16th, 1882, having bled to death from a razor wound in his groin, and was buried at Eccleshall. He married a daughter of Robert Rodgers, of Sheffield, and by her had two sons and two daughters. The elder son, Arthur, became a solicitor; the younger son, Harold, a barrister. Thomas had as one of his first dressers at the Infirmary 'Jim Bennett', who was afterwards Sir James Risdon Bennett, President of the Royal College of Physicians of London. Thomas was one of the earliest, if not the first, to use ether as an anaesthetic in Sheffield (Jan 30th, 1847). It was first administered at the Massachusetts General Hospital, Boston, on Oct 17th, 1846, and at University College, London, on Dec 21st, 1846.