CYON, ELIE DE (Tsion, Ilya Faddeyevich; 1842–1912), Russian physiologist. Cyon, who was born in Samara (now Kuibyshev), graduated from the University of Kiev and later studied in Berlin and France. In 1870 he became the first Jewish professor in Russia when he was appointed to the chair of physiology at the University of St. Petersburg. In 1872 he was appointed professor at the Medico-Surgical Academy in St. Petersburg and reformed the teaching of physiology by introducing the method of illustrative experiments. His work on reflexes won him international renown. As a result of political intrigues, Cyon was obliged to resign from the Academy in 1875. He thereafter gave up his scientific career and left Russia for Paris. Cyon published original work on the physiology of the nervous system and the heart, the mechanism of blood pressure, the application of electrotherapy, and a monograph on the inner ear. His treatise on new methods and techniques in physiological experiments served as a guide in many European medical centers. His publications include: Methodik der physiologischen Experimente und Vivisektionen… (1876); Gesammelte physiologische Arbeiten… (1888); Dieu et Science: Essais de psychologie des sciences… (1910).