Virchow, FIHR koh, Rudolf (1821-1902), was a prominent German physician, scientist, and statesman. He helped develop pathology (the study of diseased body tissue). Virchow believed that the cell is the basic unit of human life and that disease results from disturbances in the function of cells. He showed that the effects of disease could be detected by observing cells through a microscope. Virchow described his findings in his book Cellular Pathology (1858).