German physiologist; born in Berlin Oct. 21, 1838; M.D. Berlin, 1859. He engaged in practise in his native city, and in 1865 became privat-docent at its university. In 1868 he was appointed professor of physiology at Zurich, and in 1884 he accepted a similar chair at the University of Königsberg. His chief works include: "Lehrbuch der Physiologie," 12th ed., Berlin, 1900; "Handbuch der Physiologie" (together with other physiologists), 6 vols., Leipsic, 1879-81; "Leitfaden für das Physiologische Praktikum," ib. 1898; "Lehrbuch der Experimentellen Toxikologie," Berlin, 1894; "Physiologische Jahresberichte," beginning with 1873. His essays, most of which have appeared in Pflüger's "Archiv für die Gesch. der Physiologie" and in Poggendorff's "Annalen für Physik," cover nearly the whole field of physiology and part of that of physics. Most of them deal with muscular and nervous physiology, the organs of sense, and the nature of phonetics.