MULLER, JOHANNES PETER German physiologist and comparative anatomist, was born in Coblenz on July 14, 1801. He studied at Bonn university, where he taught from 1824 until 1833, when he received the chair of anatomy and physiology at Berlin. He died on April 28, 1858. The appearance of his Handbuch der Physiologie des Menschen, 1833-40 (Eng. trans., Dr. William Baly, London, 1842) marked the beginning of a new period in the study of physiology, by showing its de pendence on the other sciences. The most important part of the work deals with the physiology of the nerves and the senses. Here Muller first declared that the kind of sensation following stimula tion of a sensory nerve depends not on the mode of stimulation, but upon the nature of the sense-organ which transmits it to other nerve-terminals, and expounded the mechanism of voice, speech and hearing. Muller is also noted for his early investigations of specific nerve energies, his discoveries of the foetal Miillerian duct (1825) and of the lymph-hearts in the frog (1832), his work on tumours (1838) and his description of the parasitic disease, psorospermosis (1841). In the later part of his life he devoted
himself to the study of ocean fauna and comparative anatomy.
In addition to his Handbuch der Physiologie, Muller published Zur vergleichenden Physiologie des Gesichtssinns (1826) ; Ueber die phantastischen Gesichtserscheinungen (1826) ; Bildungsgeschichte der Genitalien (1830) ; De glandularum secernentium structura (1830) ; Vergleichende Anatomic der Myxinoiden (1834-43) ; Systematische Beschreibung der Plagiostomen (1841) with F. G. J. Henle ; System der Asteriden (1842) and Horae ichthyologicae (1845-49) with F. H. Troschel.