1833 studies at the University of Giessen under Liebig; 1835 change to Berne and studies of anatomy and physiology under Valentin; 1839 medical diploma; from 1839 onward collaboration in a project headed by Agassiz; stay at Paris; return to Giessen where he taught zoology; 1842 Reichsregent; activities in the Revolution of 1848 which forced him to go to Geneva where he taught geology; naturalized citizen of Geneva and political career as conseiller aux états and conseiller national; 1872 chair of zoology and director of the Institute of Zoology until his death.