Dr. Duncan, born in St Andrews on 17 October 1714 and educated at its university, trained in medicine in Edinburgh and became an active and influential member of the Medical Society, serving repeatedly as treasurer and president and playing a leading role in establishing its Hall. After a notable voyage to China in 1768–69 as surgeon to an East India Company ship, he took his MD at St Andrews and became a licentiate of the Royal College of Physicians. He pioneered private medical lecturing in Edinburgh, published several influential works, and, despite being unfairly passed over for a university chair, attracted large and loyal classes. In 1776 he founded the Edinburgh Dispensary, an institution that went on to benefit hundreds of thousands of patients, and he later established the long-running Annals of Medicine. In 1789 he succeeded Dr. James Gregory as professor of the Theory of Medicine, a post he held until shortly before his death.