Born at Libochovice (now in the Czech Republic), Purkinje began studying to be a priest but changed to medicine and graduated MD from Charles University, Prague, in 1819. He became professor of physiology and pathology at the University of Breslau in 1823 but returned to Charles University in 1850 to take the chair of physiology, which he held until his death. Purkinje's most celebrated research was concerned with the eye, although he also did valuable work on the brain, muscles, sweat glands, digestion, animal and plant cells, and embryology. He explored various aspects of vision, drawing attention, for example, to the fact that in subdued light blue objects appear brighter to the eye than red objects – the Purkinje effect. He located Purkinje cells in the middle layer of the brain's cerebellar cortex and was the first to apply the term ‘protoplasm’ to the living embryonic material contained in the egg. He also discovered, in the inner walls of the ventricles of the heart, the Purkinje fibers, which transmit the pacemaker stimulus. His comparative studies of cellular structure in plants and animals were continued by Matthias Schlieden and Theodor Schwann and led to subsequent increased knowledge of the factors involved in inheritance. Purkinje was among the first to use a microtome for preparing thin slices of tissue for microscopic examination, and may have been the first to teach microscopy and microscopical technique as part of his college courses. He also realized that fingerprints can be used as a method of identification.