Joseph Barcroft was born at the Glen, Newry, County Down on 26 July 1872, the second of five children.1-3 His parents, Henry and Anna, were Quakers, originally from Lancashire. His father worked in textiles (linen) and became deputy lieutenant of County Down and high sheriff of County Armagh. Joseph went to school at Bootham, the Friend's School at York, and then the Leys School, Cambridge. While still a schoolboy he was awarded a BSc (London, 1891).

After considering both the law and medicine, he opted for a career in physiology. Entering King's College Cambridge as an exhibitioner in 1894, he obtained first class honours in natural sciences (BA, 1896), was made a fellow of Kings (1899), won the Walshingham Medal for biological research (1899), and in 1900 shared the Gedge Prize for physiological research with H H Dale. That same year he was appointed to a lectureship in natural science at Kings, a post he held for 25 years. By the outbreak of the Great War he had already achieved international recognition for his work on the respiratory function of blood; a monograph with that title published in 1914 is still regarded as a classic. He also invented the Barcroft differential blood gas manometer and led two high altitude expeditions to Teneriffe (1910) and Monte Rosa (1911). In 1910 he was elected a fellow of the Royal Society.1-3

During the Great War he worked as civilian chief physiologist at …