The Bartholin family were a family of Danish physicians (Latin: Bartholinus). Caspar Berthelsen Bartholin (1585–1629) was the author of the much-used Institutiones Anatomicae (1611). This was enlarged by his son, Thomas Bartholin (1616–1680), noted also for his study of the human lymphatic system (1652). Erasmus Bartholin (1625–1698), brother of Thomas, in 1669 discovered the phenomenon of double refraction in Iceland spar crystals. Caspar Bartholin (1655–1738), son of Thomas, was the first to describe what became known as Bartholin's glands.