Born in Dublin on 23 October 1865, the fourth child and second son of Commissary Major-General Latham Blacker, a member of the Co Tyrone landed and military family, and Harriette Demaine Bagot-Smith, his wife. He was educated at Cheltenham College and University College, London, where he won an exhibition in 1888. He afterwards became president of the Old Cheltonian Society. He won the gold medal in anatomy, materia medica, and pharmaceutical chemistry at the London MB examination 1891, was elected Atkinson Morley surgical scholar at University College Hospital, and again won gold medals in surgery and in obstetric medicine at the MD examination in 1893. He was appointed assistant obstetric physician to University College Hospital and lecturer in obstetrics at University College. Although obstetricians were then classed as physicians, Blacker took the surgical Fellowship in 1891 and kept abreast of the surgical aspect of his specialty; he was elected FRCP in 1902. He was also a Fellow of University College. He examined for the Conjoint Board and for the Universities of London, Liverpool and New Zealand. During the war of 1914-18 he served as a captain in the RAMC and was twice mentioned in despatches. He became particularly interested in the work of the British Red Cross Society, and after his retirement served as president of the Farnham branch. On returning to civilian practice Blacker was appointed dean of University College Medical School. During his deanship the Rockefeller Foundation made gifts of more than one million pounds to the development, under Blacker's guidance, of the clinical unit system. The income from half a million was set apart for research with the upkeep of 120 beds. Blacker had been president of the section of obstetrics and gynaecology the Royal Society of Medicine in 1917-18, and in the early twenties took an active part in the discussion started there by T Watts Eden the reform of obstetric teaching. There and in letters to the professional journals Blacker advocated the provision of four or more large lying-in institutions, for teaching at each the whole range of midwifery, gynaecology, maternal and child welfare, by whole-time paid teachers, to all medical students in London. He was created CBE in 1920 and knighted three years later. He promoted the use of radiation in the early treatment of cancer of the uterus, became a vice-president of the Mount Vernon Hospital and president of the Radium Institute in 1929. Blacker retired in 1930 to Hampshire, moving later to Oak Hill, Frensham, near Farnham, Surrey. He was elected consulting obstetric physician to University College Hospital and to the Royal Northern Hospital. Blacker married in 1904 Shirley Elvina, second daughter of the Rev T J Bowen, a canon of Bristol, who survived him with one son. He died at Frensham on 21 May 1948, aged 82. He was a man of simple tastes and quiet mind, with a public-spirited devotion to the improvement of his chosen specialty. Publications:- Galabin's *Practice of midwifery*. 7th ed 1910. Twilight sleep, its advantages and disadvantages. *Lancet*, 1918, 1, 430. Ectopic gestation, in Eden and Lockyer's *New system of gynaecology*, 1917. Ante-partum and post-partum haemorrhage. Encyclopaedia of diseases of women. Menorrhagia, in Latham and English's *System of treatment*. Limitations of caesarean section, a review. *J Obstet Gynaec Brit Emp*. 1921, 28, 447.