William Farr CB (30 November 1807 – 14 April 1883) was a British epidemiologist, regarded as one of the founders of medical statistics. Early life William Farr was born in Kenley, Shropshire, to poor parents. He was effectively adopted by a local squire, Joseph Pryce, when Farr and his family moved to Dorrington. In 1826 he took a job as a dresser (surgeon's assistant) in the Salop Infirmary in Shrewsbury and served a nominal apprenticeship to an apothecary. Pryce died in November 1828, and left Farr £500 (), which allowed him to study medicine in France and Switzerland. In Paris he heard Pierre Charles Alexandre Louis lecture. Farr returned to England in 1831 and continued his studies at University College London, qualifying as a licentiate of the Society of Apothecaries in March 1832. He married in 1833 and started a medical practice in Fitzroy Square, London. He became involved in medical journalism and statistics. General Register Office In 1837 the General Register Office (GRO) took on the responsibility for the United Kingdom Census 1841. Farr was hired there, initially on a temporary basis to handle data from vital registration. Then, with a recommendation from Edwin Chadwick and backing from Neil Arnott, Farr secured another post in the GRO as the first compiler of scientific abstracts (i.e. a statistician). Chadwick and Farr had an agenda, demography aimed at public health, and the support of the initial Registrar General Thomas Henry Lister. Lister worked with Farr on the census design, to forward the programme. Farr was responsible for the collection of official medical statistics in England and Wales. His most important contribution was to set up a system for routinely recording the causes of death. For example, for the first time it allowed the mortality rates of different occupations to be compared. Learned societies and associations In 1839, Farr joined the Statistical Society, in which he played an active part as treasurer, vice-president and president over the years. In 1855 he was elected Fellow of the Royal Society. He was involved in the Social Science Association from its foundation in 1857, taking part in its Quarantine Committee and Committee on Trades' Societies and Strikes. Law of epidemics In 1840, Farr submitted a letter to the Annual Report of the Registrar General of Births, Deaths and Marriages in England. In that letter, he applied mathematics to the records of deaths during a recent