Born 4 May 1876, the only child of George Mayou, MD, and Adela Coombes Showers, his wife; his father was in practice at Monmouth. He was educated at the Hereford Cathedral School and at King's College Hospital, where he won the Warneford scholarship and the Jelf medal in 1896. He gained the Jacksonian prize at the Royal College of Surgeons in 1904 with an essay on "Conjunctivitis, its pathology, causes, and treatment" and in 1905 as Hunterian professor of surgery and pathology he lectured on "The changes produced by inflammation in the conjunctiva". In 1906 he was appointed pathologist and radiographer at the Central London Ophthalmic Hospital, was elected assistant surgeon in 1907 and surgeon in 1913 in succession to Ernest Clarke. Here he carried on the work inaugurated by T Brittin Archer, MRCS, and it was mainly owing to his instrumentality that a private ward for paying patients of limited means was added to the hospital under the name of the Princess Marie Louise Ward. In 1918 he was appointed consulting surgeon to the London County Council at St Margaret's Hospital, Kentish Town, for the treatment of ophthalmia neonatorum, and in this position did much good work by teaching students and midwives. In 1927 he followed E Treacher Collins as visiting ophthalmic surgeon to the White Oak Hospital at Swanley, Kent, which was then under the control of the Metropolitan Asylums Board. The White Oak institution was originally opened for the treatment of trachoma, but was used afterwards for patients suffering from interstitial keratitis, chronic conjunctivitis, and diseases of the cornea. Mayou was also ophthalmic surgeon to the Bolingbroke Hospital, the Foundling Hospital, the Seamens Hospital, Greenwich, the Ear, Throat, and Nose Hospital in Golden Square, the Infants Hospital, Vincent Square, the Children's Hospital, Paddington Green, the Hospital for Epilepsy and Paralysis, Maida Vale, and the Charterhouse Rheumatic Clinic. Mayou was an original member of the section of ophthalmology of the Royal Society of Medicine, treasurer of the Council of British Ophthalmologists, and liaison officer between the two bodies. In 1930 he served as the representative of the British Medical Association on the National Ophthalmic Treatment Board. He was elected president of the Ophthalmological Society of the United Kingdom in 1933, and died during his two years' tenure of the office on 20 July 1934, at 70 Portland Court, W. He married Daphne Lyla England on 13 March 1913, who survived him with three daughters. He made many contributions on pathology, comparative and clinical, to the *Royal London Ophthalmic Hospital Reports*, *The Ophthalmoscope*, and various other ophthalmological journals in England and the United States. He was also interested in the mechanical side of ophthalmic work, for he invented the Mayou operating lamp and the Mayou slit-lamp, as well as numerous instruments. Mayou was an enthusiastic fisherman, who discussed the question of colour vision in fish, a keen golfer, and an ardent horticulturist at Alison House, Camberley. He served as worshipful master of the Captain Coram Lodge, and was ophthalmic surgeon to the Masonic Hospital and to the Masonic Schools. Publications: *The changes produced by inflammation in the conjunctiva*, Hunterian lecture. London, 1905. *Diseases of the eye*. *Ibid*. 1908; 4th edition, 1933. *Pathology and bacteriology of the eye*, with E Treacher Collins. London, 1911; 2nd edition, 1925.