German pathologist who studied under Johannes Müller. Virchow opposed the idea that disease was an affliction of the body at large or one of its humor, wanting to find the anatomical location of diseases. In Die Cellularpathologie (Cellular Pathology, 1858), he set out methods and objectives of pathology and demonstrated that cell theory applied to diseased tissue as well as healthy. He summarized the cell theory with the Latin phrase "omnis cellula a cellula" (all cells arise from cells) in 1855. However, he did not accept Pasteur's germ theory, and in later life devoted himself to archaeology and anthropology, forming a close friendship with Schliemann and collaborating in the excavation of Troy.