1-158-237 - Oxford Science Archive/Heritage Images

Descartes' representation of the antagonistic eye muscles, 1692. When E is relaxed A is innervated. Rene Decartes (1596-1650) believed that an animal spirit travelling down hollow nerves C and B contracted the muscles and blew them up, and that they relaxed when the spirit was shut off by valves. From Opera Philosophica by Rene Descartes. (Frankfurt-am-Main, 1692). Originally published in his Tractatus de homine. (Paris, 1664).