Rudolf Virchow (1821–1902) was a German physician, liberal politician and archaeologist. He founded modern pathology and was the first to describe the symptoms of leukemia, a name that he designated. He is also one of the founders of the Berliner Gesellschaft für Anthropologie, Ethnologie und Urgeschichte.
George Engelbach (1817–1894), Rudolf Virchow (1821–1902), lithograph, undated; source: National Library of Medicine, http://resource.nlm.nih.gov/101408082, public domain.