Theodor. 1810-1882 Student of Johannes Müller in Berlin; Louvain & Liège anatomist & physiologist; discovered pepsin (1835); recognized cell is basic unit of life (1838, founder of cell theory with Schleiden, q.v.); showed bile is essential for digestion (1844); S. cells = neurilemma cells making myelin sheath; sheath of S. = neurilemma = myelin sheath (1839).

German physiologist and histologist who in 1838 and 1839 identified the cell as the basic structure of plant and animal tissue (1810-1882)

Sheath of, the neurilemma. Substance of, the myelin sheath which surrounds the nerve fibers of the central nervous system.