Born in 1799 at East Brunton, Gosforth, Northumberland, he was descended from the family of Dunn, lairds of Matfen, Co Northumberland and through his mother from the family of Ridley. He was educated at Atkinson's private school in Newcastle, was apprenticed to W Davison, of Alnwick, and at the age of twenty-three entered the United Borough Hospitals of St Thomas and Guy's in London. He practised throughout his life at 31 Norfolk Street, Strand, and was on the staff of the Carey Street Dispensary, where his friend Thomas Addison was physician. He was an original associate of the Obstetrical Society of London, vice-president of the Royal Medical and Chirurgical Society, and president of the Metropolitan branch of the British Medical Association. He died 4 November 1877; but his record was inadvertently omitted from the *Lives of the Fellows*, published in 1930. Publications:- On the inhalation of chloroform. *Lond Med Gaz*. 1851, 48, 281. *An essay on physiological psychology*. London, 1858. *Ethnology*, three papers read before the Ethnological Society, London, 1851.