After a short period of practice as a physician in Cornwall, he settled in London. He was elected F.R.S. 1728, and a fellow of the Royal College of Physicians 1732. He attended some of Winslow's lectures in France, and saw Giovanni Battista Morgagni and Santorinus in Italy; and on his return began to give anatomical lectures in London. In 1734 he gave the Gulstonian lectures at the College of Physicians, ‘On the Structure of the Heart and the Circulation of the Blood;’ and again in 1736 ‘On the Urinary Organs, with the Causes, Symptoms, and Cure of Stone.’ He delivered the Harveian oration in 1739, and the Lumleian lectures 1748–9, of which the inaugural lecture, ‘De Anima Medica,’ was given 16 December 1748, and was published in 1750 (2nd edit. 1771; 3rd edit. 1773).