William Cullen. Engraving of William Cullen (1710-90), Scottish physician and chemist. Originally educated in mathematics, Cullen began attending medical classes at Glasgow and Edinburgh Universities. In 1747 he began teaching chemistry at Glasgow and in 1755 was offered a professorship in Medicine. His teaching at both Glasgow and Edinburgh was highly influential; his pupils included the chemist Joseph Black and the anatomist William Hunter. Cullen also emphasised the importance of the nervous system in illness and invented the phrase 'neurosis' to describe a group of nervous diseases.