Portrait of Johannes Purkinje (1787-1869), Czech histologist and physiologist. Purkinje was educated by monks, initially for the priesthood, then philosophy and finally medicine. He graduated in 1818, publishing his well-known thesis on vision. This established his reputation, and he took professorships at Breslau and, later, Prague. With his use of the compound microscope he made many new observations, describing ciliary motion in 1835. Two years later he produced an outline of cell theory. At the same time, he described nerve cells in the cerebellar cortex, now known as Purkinje cells. Other histological advances included the use of the microtome.