William Cullen FRS FRSE FRCPE FPSG was a Scottish physician, chemist and agriculturalist, and professor at the Edinburgh Medical School. Cullen was a central figure in the Scottish Enlightenment: He was David Hume's physician, and was friends with Joseph Black, Henry Home, Adam Ferguson, John Millar, and Adam Smith, among others.
He was President of the Royal College of Physicians and Surgeons of Glasgow, President of the Royal College of Physicians of Edinburgh and First Physician to the King in Scotland. He also assisted in obtaining a royal charter for the Philosophical Society of Edinburgh, resulting in the formation of the Royal Society of Edinburgh in 1783.
Cullen was a beloved teacher, and many of his students became influential figures.