Born on 11 May 1862 at Birmingham, the son of Oglethorpe Wakelin Barratt MRCS, he was educated at University College, London. Although he took the Fellowship soon after qualifying, Barratt never practised surgery but spent his life in research, producing valuable work in a variety of fields. While making postgraduate study at Göttingen and Munich he contributed papers to the German journals of physiology and bacteriology. He worked in the physiology and pathology departments at University College 1893-96, was a research scholar in neuropathology in the London County Council's asylums 1897-99 and pathologist to the West Riding Asylum at Wakefield 1899-1903. He held a British Medical Association research scholarship 1903-05 and then, after a year as assistant bacteriologist to the Lister Institute, spent a year (1906-07) in the Cytology and Cancer Research Department of Liverpool University. The Liverpool School of Tropical Medicine sent him to Nyasaland in 1907 as senior member of its Blackwater Fever Expedition. His valuable findings were published between 1909 and 1911, while he was director of cancer research at Liverpool. He came back to the Lister Institute in 1913 with a Beit memorial fellowship to research on blood plasma and serum reactions. This work was interrupted by his service in France during the war of 1914-18 as a Captain RAMC with the 1st City of London Sanitary Company. Wakelin Barratt was Master of the Society of Apothecaries in 1933-34. He married Dr Mary Muter Gardner of Stonehouse, Lanark, in 1913, and she survived him. He lived at 56 Alfriston Road, Clapham Common, and died on 1 December 1956 aged 94.