Theodor Schwann (7 December 1810, Neuss – 11 January 1882)

Theodor Schwann 

(7 December 1810, Neuss – 11 January 1882)

Theodor Schwann (7 December 1810, Neuss – 11 January 1882) was a German physiologist. His many contributions to biology include the development of cell theory, the discovery of Schwann cells in the peripheral nervous system, the discovery and study of pepsin, the discovery of the organic nature of yeast, and the invention of the term metabolism.

Vitalism and germ theory

He was the first of Müller's pupils to break with vitalism and work towards a physico-chemical explanation of life. Schwann's rediscovery of the cell came when he was paying particular attention to the cytoplasm of a plant cell, and noticed its jelly-like consistency. He went on to view animal cells, and noted that they had different properties. Müller also directed Schwann's attention to the process of digestion, which Schwann showed in 1837 to depend essentially on the presence of a ferment he called pepsin. Schwann also examined the question of spontaneous generation, which led to its eventual disproof. In the course of his experiments, he discovered the organic nature of yeast. In fact, the whole germ theory of Pasteur, as well as its antiseptic applications by Lister, can be traced to Schwann's influence.

http://en.wikipedia.org/wiki/Theodor_Schwann