His brother was the physician Henry Cullen .
Born on 22 September 1742 , in Edinburgh , the son of eminent physician and chemist William Cullen and Anne Johnstone ( d. 1786 ) .
William Cullen 's brother was the physician Henry Cullen .
Born on 22 September 1742 , in Edinburgh , the son of eminent physician and chemist William Cullen and Anne Johnstone ( d. 1786 ) .