Barker, Francis (1773–1859), physician and chemist, was born in Waterford, the eldest son of six children (five sons and a daughter) of William Barker (1731–88), pharmacist, alderman and sheriff of Waterford (1759–63), and Elizabeth Barker (née Acheson) of Duncormuck, Co. Wexford. He entered TCD in October 1788 and graduated BA (1793). He then studied at Edinburgh (where he came to know Sir Walter Scott), graduating MD (1795) with a thesis on the work of Galvani that suggested the identity of the nervous fluid with dynamical electricity. Returning to Waterford, he investigated the prevalence of fever for a local committee that intended to found a fever hospital in the city. In about 1800 he moved to Dublin, and became assistant lecturer in chemistry (1801) and assistant professor of chemistry (1803) at TCD. Despite these appointments he was primarily a physician. He and Whitley Stokes (qv) inaugurated the first formal series of clinical lectures in Ireland in the Meath Hospital from November 1803. In 1804 he was appointed senior physician to Cork St. fever hospital, and became licentiate (1805), fellow (1807), and honorary fellow (1813) of the K&QCP(I).
In 1808 he was appointed professor of chemistry at TCD, and in 1810 was awarded MB and MD degrees. With three other doctors he founded the quarterly Dublin Medical and Physical Essays, the first Irish medical journal, which was published from March 1807 to June 1808. He was secretary (1820–52) of the General Board of Health, founded after the epidemics of 1816–19, which advised the government on public health, investigated the living conditions of the poor and inspected dispensaries and fever hospitals. Barker published many valuable reports on fevers, notably An account of the rise, progress and decline of the fever lately epidemical in Ireland (2 vols, 1821) in collaboration with John Cheyne (qv), which highlighted the effects of poverty and poor hygiene in the spread of typhus 1816–19. The report maintained that the establishment of local fever hospitals by county grand juries under legislation passed in 1818 was one of the most effective means of fighting disease. Shortly after the publication of the report, Barker was commissioned to investigate the fever epidemic in Munster. In 1828 he also published an annotated translation of the Dublin Pharmacopoeia. He retired from TCD in 1850. He died 8 October 1859 at Wellington Road, Dublin, and was buried at Mount Jerome cemetery.
In 1804 he married Emma, daughter of Arthur Conolly, vicar of Donard, Co. Wicklow; they had four daughters and a son William (1810–73), who was professor of chemistry (1850–73) at the RCSI.