In 1800 he moved to Hertford, where he introduced vaccination into three parishes in spite of opposition from the doctors, but in 1802 began to practise in London, and in 1803 became a member of the College of Surgeons.
He was surgeon to the New Finsbury Dispensary, and founded a special hospital, called the Glandular Institution for the Cure of Cancer, in Clifford Street.
His entry in The Knights of England (1906) indicates that his knighthood along with one other was deemed to be "surreptitiously obtained", and there was some question as to whether they should be listed.
[3][4] The title was not revoked, but the situation was regarded with some distrust by many of his contemporaries; the College of Surgeons struck his name off the list of members as a result.
116, London, 1820, 8vo, and subsequently; also papers in "Defence of Vaccination," &c.; an "Essay on the too frequent Use of the Trephine;" on the "British System of Education;" and many articles in periodicals.