Thomas Willis (1621-1673) was an English physician who played an important part in the history of the science of anatomy, was a co-founder of the Royal Society (1662) and is often considered the 'father of neurology'. Willis worked as a physician in Westminster, London, and from 1660 until his death was Sedleian Professor of Natural Philosophy at Oxford. He was a pioneer in research into the anatomy of the brain, nervous system and muscles. The "circle of Willis", a part of the brain's vascular system, was his discovery. His anatomy of the brain and nerves, as described in his Cerebri anatomi of 1664, is so minute and elaborate, and abounds so much in new information, that it presents an enormous contrast with the vague and meagre efforts of his predecessors. This work was not the result of his own personal and unaided exertions; he acknowledged his debt to Sir Christopher Wren and Thomas Millington, and his fellow-anatomist Richard Lower. Wren was the illustrator of the magnificent figures in the book. Willis was the first natural philosopher to use the term "reflex action" to describe elemental acts of the nervous system. He also wrote Pathologiae Cerebri et Nervosi Generis Specimen, 1667 (An Essay of the Pathology of the Brain and Nervous Stock) and of De Anima Brutorum, 1672 (Discourses Concerning the Souls of Brutes).

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