Born at Sao Paulo, Brazil, on 10 September 1880, the second son of Richard Gray, railway engineer, of Sao Paulo, and Ellen Tyrrell, his wife. He was admitted to St Paul's School, London as a capitation scholar in 1894, was transferred to Foundationers in September 1896, and left from Science VII in July 1899. He matriculated at the University of London in June 1898, after he had been placed in the first-class at the examination, and entered Trinity College, Cambridge in 1899. He graduated BA with a second-class in the Natural Sciences Tripos, part 1, in 1902. He received his medical education at St Thomas's Hospital, where he served the offices of house surgeon and clinical assistant in the throat department. In 1906 he was elected resident medical superintendent at the Great Ormond Street Hospital for Sick Children, where he remained for three years. He was chosen assistant surgeon to the hospital in 1911, and surgeon in 1926. Gray was appointed assistant surgeon to the West London Hospital at Hammersmith on 2 July 1912, becoming surgeon on 27 September 1921. He was also on the staff of the Hampstead General Hospital, the Italian Hospital, the Infants Hospital, and the Royal Masonic Hospital and Nursing Home. At the Royal College of Surgeons he gave the Arris and Gale lectures in 1912 on "The mechanism of shock", a subject which had long interested him, and in 1920 a lecture as Hunterian professor of surgery and pathology on "The influence of nerve impulses on visceral disorders." He was for a time greatly interested in the surgical treatment of pyloric stenosis in infants, and contributed largely to improvements in the technique of Rammstedt's operation. The condition, which had been almost invariably fatal, was reduced by these improvements to a comparatively slight mortality. He was honorary secretary of the section of diseases of children at the Aberdeen meeting of the British Medical Association in 1914, and vice-president of the section at Nottingham in 1926. He was president of the West London Medico-Chirurgical Society in 1933. During the war he made many attempts to join the Army, but was always rejected on medical grounds. He nevertheless did much good work at Queen Mary's, King George's, and other war hospitals. He was keenly interested in craft masonry, was a founder of the Old Pauline Lodge in 1919, and was appointed a past grand deacon of England in 1932. He married Elizabeth Gibson Whitelaw, the adopted daughter of Mrs Parker Jervis of Egerton Gardens, on 28 November 1912, who survived him with a son and three daughters. He died on 6 February 1935, and was buried in the St Marylebone cemetery, East Finchley. Tyrrell-Gray was a surgeon with original ideas, a highly skilled operator, more especially in abdominal work, where his great technical ability showed to the best advantage. He did a very large amount of surgical work in spite of the fact that during the whole of his professional life he was handicapped by ill-health, originating in an attack of pneumonia followed by pleurisy with effusion. In spite of this handicap he never spared himself or lost the hopeful spirit which often led his patients to a successful issue, when others had despaired of their recovery. Personally he was of slight build and sallow complexion. His suggestions were well thought out and were expressed in clear terms. They were based on common-sense arguments and usually carried conviction. He was so good an executive musician that he thought at one period of his career that he would adopt music rather than surgery as a profession. Publications: Pathology and treatment of shock, Arris and Gale lectures, with Leonard Parsons. *Brit med J* 1912, 1, 938 and 1004; 2, 106. Congenital hypertrophic stenosis of the pylorus, with G R Pixie. *Lancet*, 1919, 2, 5. The influence of nerve impulses on visceral disorders, Hunterian lectures. *Lancet*, 1920, 1, 1299.