Koch, kawhk or kohk, Robert (1843-1910), a German physician, played a key role in helping bacteriology develop as a science during the 1800's. He introduced new techniques of staining and culturing (growing) bacteria, and he became the first scientist to show that specific bacteria cause certain diseases. Koch discovered the causes of tuberculosis and other diseases. He received the Nobel Prize in physiology or medicine in 1905 for his work on tuberculosis.