William Cullen, Scottish physician and chemist (died 1790)

William Cullen was a British physician, chemist and agriculturalist from Hamilton, Scotland, who also served as a 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.

April 15 is the 105th day of the year in the Gregorian calendar; 260 days remain until the end of the year.