Born 8 June 1870 at Neas, Dungannon, North Ireland, the eldest of he four children of John Hewitt, schoolmaster, of Kingstown, Co Dublin, and Annie Sophia Porter his wife. He was educated at the Royal School, Dungannon, at the Galway College of the Royal University of Ireland, at Edinburgh, and at St Bartholomew's Hospital, London. For a short time he acted as a clinical assistant at St Peter's Hospital for Stone in Henrietta Street, Covent Garden. He entered the Royal Navy as a surgeon in November 1897. Early in his service he showed promise of a distinguished career, being commended in 1904 for his assistance on the subject of the treatment of wounded in ships during and after action. He contributed an article entitled "Treatment of wounded in naval warfare" to the *British Medical Journal*, 1914, 2, 257. He was specially promoted to Fleet Surgeon (Surgeon Commander) in 1911 for conspicuous professional merit. Up to 1913 he had served in various ships at home and abroad, but in that year he was appointed as an Assistant to the Medical Director-General, in which post he served for six years, and throughout the war of 1914-18, with marked success. In 1918 he was made CMG in recognition of services rendered during the war. He was specially selected as senior medical officer for the North Russian Expeditionary Force, in which appointment he was in charge of the medical arrangements for both the Navy and the Army. He was strongly commended for his untiring, farseeing, and excellent arrangements, and was made CB (military) for these valuable services in 1919. Proceeding to sea once more, he continued to show considerable powers of organization and proved a competent operating surgeon as principal medical officer of the new hospital ship Panama, afterwards renamed Maine. His service was concluded as Surgeon Rear-Admiral in charge of the RN Hospital at Haslar from 1926 until 1929, when he was placed on the retired list at his own request. All who served with Surgeon Vice-Admiral D W Hewitt became impressed with his zeal. No appreciation of him, as a doctor and an officer, can be better expressed than in the words of a senior officer at the end of his service: "By his solicitude for the patients and the sympathy he shows to relatives and dependents, he has endeared himself to all classes, and I fully believe that Haslar Hospital stands even higher in the general estimation than in the past." He was a loyal friend, ever ready to lend a helping hand to his juniors. He married Nora Gertrude Pinkey on 11, February 1908. She survived him, with a son and two daughters. He died on 25 October 1940 at Lindhu, Alverstoke, Hants.