Born on 23 October 1872, the son of the Rev John Ferguson MacCallan MA, Vicar of New Basford, Notts, and Elizabeth his wife, daughter of Thomas Danks, chairman of the Nottingham and Nottinghamshire Bank, MacCallan was educated at Nottingham High School, Charterhouse School, Christ's College, Cambridge, and St Mary's Hospital, London, where he won a university exhibition. He served as house surgeon for three years at the Royal London Ophthalmic Hospital, Moorfields, and afterwards as chief clinical assistant, and was for a short time assistant ophthalmic surgeon at Westminster Hospital. He was appointed in 1903 to organise the new Egyptian ophthalmological service under the trust established by Sir Ernest Cassel, whose purpose was to conduct a vigorous campaign against trachoma throughout the country. MacCallan had to establish and maintain a series of provincial hospitals, train a corps of ophthalmic surgeons to the highest scientific standard from among the young Egyptian doctors seconded to him by the Department of Public Health, and himself practise as a whole-time salaried surgeon in the public service. He spent most of the nine years till 1914 travelling among his hospitals, but he had frequent contact with individual members of the government, ranging from successive Eygptian Khedives and Kings, British High Commissoners, Ministers, and senior civil servants to the local officials in the country. He was President of the Ophthalmological Society of Egypt in 1913. In 1912 by order of Lord Kitchiner, the High Commissioner, he undertook a survey of the incidence of ankylostomiasis and bilharziasis in two provinces of Egypt, published a detailed report, and organised two travelling hospitals. As a result of this work he was appointed, against his own wishes, head of the epidemiological section of the Department of Public Health in 1913. His Cambridge MD thesis of 1913, on trachoma and its complications in Egypt, was awarded the Darwin prize by Christ's College. He was on leave in England in August 1914 when war broke out, and was ordered to return at once to Egypt by Lord Kitchiner, who was now in London as Secretary of State for War. He reorganised the five ophthalmic hospitals in North Egypt to receive casualties from the Gallipoli campaign (1915). He also sent three of his travelling ophthalmic hospitals to Ismailia and Suez to receive Turkish wounded. The British Director of Medical Services described his 700-bed camp hospital as "the model of what a hospital under canvas should be". This hospital was transferred to Cairo and evacuated in 1916 (*Ophthalmoscope*, December 1916, 14, 650). In February 1916 MacCallan was posted by the General Officer in command of the British Army in Egypt to serve as senior medical officer with the rank of Major RAMC at the base of Mersa Matruh on the Mediterranean coast of the Western Desert province. In March 1916 he volunteered to take food and medical supplies through the Turkish lines in Libya to starving British prisoners from the ship *Tara*, which had been wrecked on the African coast. They were, however, rescued by the Duke of Westminster's armoured-car raid before MacCallan started on this audacious venture. He was mentioned in dispatches and created OBE in 1918. He returned to civil ophthalmic work - administration, teaching, and surgery - in Egypt in 1917. The Egyptian Government appointed him in 1923 as director general of the epidemic services and general hospitals, but he resigned and returned to London, where he practised at 33 Welbeck Street, and was appointed ophthalmic surgeon to Westminster Hospital, and surgeon to the Royal Eye Hospital. He lived at the Downs, Hertford Heath. In 1925 the Memorial Ophthalmic Laboratory at Giza near Cairo was opened through his efforts, as a memorial to the men of the Egyptian labour corps and camel transport corps who had fallen in the war of 1914-18, with a grant of £6600 from the Imperial War Graves Commission. The original laboratory had been financed by the gifts of MacCallan's personal friends; the new laboratory, a fine modem building designed by Noel Dawson, was planned and equipped internally with MacCallan's expert advice. His former pupils subscribed for a bronze bust of him by Doyle Jones, which was placed in the laboratory in 1931; a replica of the head was presented to him. His principal assistants had been L S Miller, afterwards of Hobart, Tasmania; Granville Waddy, of Sydney; E V Oulton, of Brighton; and M Sobhy, afterwards Professor at Cairo. His services were rewarded with the CBE, the Turkish Order of the Medjidieh (third class), and the Egyptian Order of the Nile (second class). He was also honoured by the Order of St John of Jerusalem. He was a Hunterian Professor at the College in 1936. MacCallan took a prominent part in the international campaign against blindness. He was elected President in 1935 of the International Organisation against Trachoma, and was given a seat ex officio in 1936 on the International Council of Ophthalmology; he was re-elected quadrennially to the presidency up to 1954, when he was elected Honorary President for life. His classification of trachoma (*Archives d'Ophtalmologie* 1911, 31, 600) came into use all over the world and was adopted by the committee of experts appointed by the World Health Organisation after the second world war. When the Egyptian government terminated the employment of British citizens in the 1950s, MacCallan became chairman of the Anglo-Egyptian Association, which negotiated successfully with the British and Egyptian authorities to secure compensation for loss of pensions. He married in 1918 Hester McNeill, daughter of the Rt Rev William Boyd-Carpenter KCVO, Bishop of Ripon (1884-1911). He died on 31 March 1955 aged 82, survived by his wife and their two sons and one daughter. A memorial service was held in Westminster Hospital Chapel on 6 April 1955. Mrs MacCallan died on 25 March 1960. Publications: Trachoma. *Ophthalmoscope* 1908, 6, 856; 947. Trachoma. *Arch Ophtal Paris* 1911, 31, 600. *Trachoma and its complications in Egypt*. Cambridge University Press 1913. Acute conjunctivitis in Egypt. *Bull Ophthal Soc Egypt* 1915, p. 37. Slight injuries of the head and optic nerve changes, with A F El Rasheed. *Bull Ophthal Soc Egypt* 1917, p. 34. The pathognomonic signs of trachoma. *Bull Ophthal Soc Egypt* 1920, p 15. Notes on the history of ophthalmology in Egypt. *The same* p 64. Causes of blindness in Egypt. *Bull Ophthal Soc Egypt* 1922, p. 22. Interesting cases seen in 1921. *The same* p 56. *Trachoma*. London, Butterworth 1936 (also many translations). The ophthalmic campaign in Egypt. *Rev int Trachome*, 1948, 25, 1, with portrait. Trachoma. *Brit Encyc Med Practice*, 2 ed., 1950, 12, 274-293.