CYON, ELIA von. - Russian physiologist, b. at Telschi in 1843, d. at Paris in 1912. In the first phase of his scientific activity he discovered the accelerator nerves of the heart and (with the German physiologist K. F. W. Ludwig) the depressor nerve (1866), discoveries for which he remains deservedly famous.
Professor at Pietroburgo until 1877, he left Russia for political reasons and in Paris devoted himself to political life and was an effective advocate of the Franco-Russian alliance. Having returned to research, he published three works that remained classics: I nervi del cuore, Le ghiandole sanguigne come organi protettori del sistema nervoso centrale and L'orecchio, which were translated
also into Italian (Bologna 1912-13). Jewish by birth, he converted to Orthodoxy toward the end of his medical studies and died a Catholic. His work Dieu et science (1910-12), written with an apologetic purpose, should be noted.