Theodor Schwann
Theodore Schwann (
December 7,
1810 -
January 11,
1882) was a
German physiologist,
histologist and
cytologist.
Among his many contributions to
biology there was the development of
cell theory, the discovery of
Schwann cells in the
nervous system, the discovery and study of
pepsin, the discovery of the organic nature of
yeast and the invention of the term
metabolism.
Histology
It was during the four years spent under the influence of
J. P. Müller at Berlin that all Schwann's really valuable work was done. Müller was at this time preparing his great book on
physiology, and Schwann assisted him in the experimental work required. Schwann's attention was directed to the
nervous and
muscular tissues. Besides making such
histological discoveries as that of the envelope of the
nerve fibers which now bears his name, he initiated those researches in muscular contractility since so elaborately worked out by
Du Bois-Reymond and others. Schwann is sometimes regarded as the "father of cytology."
Vitalism and germ theory
Schwann was thus the first of Müller's pupils who broke with the traditional
vitalism and worked towards a physico-chemical explanation of
life. Müller also directed Schwann's attention to the process of
digestion, which Schwann showed in 1836 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 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.
Cell theory
Once, when Schwann was dining with
Schleiden in 1837, the conversation turned on the
nuclei of plants and animal
cells. Schwann remembered having seen similar structures in the cells of the
notochord (as had been shown by Müller) and instantly realized the importance of connecting the two phenomena. The resemblance was confirmed without delay by both observers, and the results soon appeared in his famous
Microscopic Investigations on the Accordance in the Structure and Growth of Plants and Animals http://vlp.mpiwg-berlin.mpg.de/library/data/lit28715/index_html?pn=7 scanned source(Berlin, 1839; trans.
Sydenham Society, 1847). Thus
cell theory was definitely constituted. In the course of his verification of cell theory, in which Schwann traversed the whole field of histology, he proved the cellular origin and development of the most highly differentiated tissues including
nails,
feathers, and
tooth enamel.
His generalization became the foundation of modern histology, and in the hands of
Rudolf Virchow (whose
cellular pathology was an inevitable deduction from Schwann) afforded the means of placing modern
pathology on a truly scientific basis.
*
Cell biology*
Cell theory*
History of biology*
Michael Swann*
Short biography and bibliography in the Virtual Laboratory of the
Max Planck Institute for the History of Science
