Thomas Willis, an English physician, born at Great Bed win, Wiltshire, Jan. 27, 1621, died in London, Nov. 11, 1675. He graduated at Oxford in 1639, fought in defence of Charles I., studied medicine, and at the restoration was appointed Sedleian professor of natural philosophy in the university of Oxford. In his "Anatomy of the Brain" (4to, 1644) he first showed that the brain is a congeries of organs, and the seat of moral and intellectual action. The name " circle of Willis " has been retained for the circular arterial inosculation at the base of the brain by which the vertebral arteries behind and the internal carotids in front are united with each other, while those on the right side at the same time communicate with those on the left by similar free inosculation. He was appointed physician in ordinary to the king in 1666. He was one of the founders of the royal society. He also published a treatise on the "Pathology of the Brain and Nervous System" (1667), in which he gave the true explanation of the phenomena in the spasmodic diseases hysteria, chorea, etc.