Purkinje, Johannes (Evangelista)

[poor kinyay] (1787–1869) Czech histologist and physiologist: advanced cell theory and observed cellular division.

Educated by monks, Purkinje first trained for the priesthood; then he studied philosophy, and lastly medicine. He graduated in 1818, with a famous thesis on vision which gained him the friendship of Goethe, the poet-philosopher. Helped by this, he became professor at Breslau and later in Prague. In 1825 he first observed the nucleus in bird’s eggs; in 1832 he began to use a compound microscope, and soon made many new observations. In 1835 he described ciliary motion; in 1837 he outlined the key features of the cell theory, which was to be fully propounded by in 1839. Also in 1837 he described nerve cells with their nuclei and dendrites and the flask-like cells (Purkinje cells) in the cerebellar cortex. In 1838 he observed cell division, and the following year he was the first to use the word ‘protoplasm’ in the modern sense. His improvements in histology included early use of a mechanical microtome in place of a razor, to obtain thin tissue slices.