The German biologist Theodor Schwann (1810-1882) is considered a founder of the cell theory. He also discovered pepsin, the first digestive enzyme prepared from animal tissue, and experimented to disprove spontaneous generation.

Theodor Schwann was born at Neuss near Düsseldorf on Dec. 7, 1810. At the University of Bonn, which he entered in 1829, he met Johannes Müller, the physiologist, whom he assisted in his experiments. Schwann continued his medical studies at the University of Würzburg and later at the University of Berlin, from which he graduated in 1834. His doctoral dissertation dealt with the respiration of the chick embryo.

Contributions to Physiology and Anatomy

At the University of Berlin, Schwann again came into contact with Müller, who convinced him that he should follow a scientific career. Very soon after he began to work under Müller, he had his first success. From...