On 20 April 1816 he was elected physician at St. George's Hospital, though the youngest of the candidates, and held the post until 1839; during that period he delivered a course of lectures on practical medicine, a report of which was printed in the Medical Gazette.
Ernest, the new king of Hanover, on 8 August 1837 created him KCH; but at his urgent request allowed him to decline the assumption of the ordinary prefix of knighthood.
He continued to be the leading physician in London, with an income of from seven to nine thousand guineas a year, until 1848, when bad health obliged him to retire into private life.
His success in practice depended mainly on the clear insight which he gained into all the bearings of a case by habituating himself to place all the facts before him in the order of their importance, with reference to present symptoms and immediate treatment required.
His constant habit of taking notes of cases coming before him gave his mind a compactness and clearness in summing up facts which was the parent of practical views in theory and successful decision in action.