Theodor Schwann

For the American Union Army officer, see Theodore Schwan.

Theodor Schwann
Theodor Schwann
Born	December 7, 1810 Neuss, First French Empire (now in Germany)
Died	January 11, 1882 (aged 72)
Known for	Cell Theory Schwann Cells
Influences	Johannes Peter Müller

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.

Early life

Schwann was born in Neuss. His father was a goldsmith, later a printer. Schwann studied at the Jesuits College in Cologne, and then at Bonn, where he met Johannes Peter Müller.

Work

It was during the four years spent under the influence of Müller at Berlin that Schwann's most 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 observed animal cells under the microscope, noting that their different properties. Schwann's attention was directed to the nervous and muscular tissues. He discovered the cells which envelope the nerve fibers, now called Schwann cells in his honour. He discovered the striated muscle in the upper esophagus and initiated research into muscle contraction, since expanded upon greatly by Emil du Bois-Reymond and many others. Müller also directed Schwann's attention to the process of digestion, and in 1837 Schwann isolated an enzyme essential to digestion, which he called pepsin.

Schwann's later years were marked by increasing concern with theological issues. He died in Cologne on January 11th, 1882.

Vitalism and germ theory

Schwann was the first of Johannes Peter Müller's pupils to break with vitalism and work towards a physico-chemical explanation of life. 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 retrospect, the germ theory of Pasteur, as well as its antiseptic applications by Lister, can be traced to Schwann's influence.

Cell theory

In 1837, Matthias Jakob Schleiden viewed and stated that new plant cells formed from the nuclei of old plant cells. While dining that year with Schwann, the conversation turned on the nuclei of plant and animal cells. Schwann remembered seeing 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 Schwann's famous Microscopic Investigations on the Accordance in the Structure and Growth of Plants and Animals, in which he declared that "All living things are composed of cells and cell products". 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) placed modern pathology on a truly scientific basis.

Schwann established a basic principle of embryology by observing that the ovum is a single cell that eventually develops into a complete organism.

References

Attribution

 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Schwann, Theodor". Encyclopædia Britannica (11th ed.). Cambridge University Press. 

Further reading

• Aszmann, O. C. (May 2000). "The life and work of Theodore Schwann". Journal of reconstructive microsurgery (United States) 16 (4): 291–5. doi:10.1055/s-2000-7336. ISSN 0743-684X. PMID 10871087. 
• Florkin, M. (September 1958). "Episodes in medicine of the people from Liège: Schwann & the stigmatized". Revue médicale de Liège 13 (18): 627–38. ISSN 0370-629X. PMID 13591909. 
• Florkin, M. (September 1957). "1838; Year of crisis in the life of Théodore Schwann". Revue médicale de Liège 12 (18): 503–10. ISSN 0370-629X. PMID 13466730. 
• Florkin, M. (March 1957). "Discovery of pepsin by Theodor Schwann". Revue médicale de Liège 12 (5): 139–44. ISSN 0370-629X. PMID 13432398. 
• Florkin, M. (November 1951). "Schwann as medical student". Revue médicale de Liège 6 (22): 771–7. 
• Florkin, M. (October 1951). "Schwann at the Tricoronatum". Revue médicale de Liège 6 (20): 696–703. ISSN 0370-629X. PMID 14883601. 
• Florkin, M. (May 1951). "The family and childhood of Schwann". Revue médicale de Liège 6 (9): 231–8. ISSN 0370-629X. PMID 14845235. 

• Haas, L. F. (January 1999). "Neurological stamp. Theodore Schwann (1810-82)". J. Neurol. Neurosurg. Psychiatr. (England) 66 (1): 103. ISSN 0022-3050. PMC 1736145. PMID 9886465. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1736145. 
• Hayashi, M. (1992). "Theodor Schwann and reductionism". Kagakushi kenkyu. Journal of the history of science, Japan (Japan) 31 (184): 209–14. ISSN 0022-7692. PMID 11639601. 
• Kiszely, G. (April 1983). "Theodor Schwann". Orvosi hetilap (Hungary) 124 (16): 959–62. ISSN 0030-6002. PMID 6343953. 
• Kosinski, C. M. (December 2004). "Theodor Schwann". Der Nervenarzt (Germany) 75 (12): 1248–1248. doi:10.1007/s00115-004-1805-5. PMID 15368056. 
• Kruta, V. (1987). "The idea of the primary unity of elements in the microscopic structure of animals and plants. J. E. Purkynĕ and Th. Schwann". Folia mendeliana (Czech Republic) 22: 35–50. ISSN 0085-0748. PMID 11621603. 

• Lukács, D. (April 1982). "Centenary of the death of Theodor Schwann". Orvosi hetilap (Hungary) 123 (14): 864–6. ISSN 0030-6002. PMID 7043357. 
• Watermann, R. (January 1973). "Theodor Schwann accepted the honorable appointment abroad". Medizinische Monatsschrift (Germany, West) 27 (1): 28–31. ISSN 0025-8474. PMID 4576700. 
• Watermann, R. (December 1960). "Theodor Schwann as a maker of lifesaving apparatus". Die Medizinische Welt 50: 2682–7. ISSN 0025-8512. PMID 13783359. 

External links

• Short biography and bibliography in the Virtual Laboratory of the Max Planck Institute for the History of Science
• Schwann, Theodor and Schleyden, M. J. 1847. Microscopical researches into the accordance in the structure and growth of animals and plants. London: Printed for the Sydenham Society
•  "Theodor Schwann". Catholic Encyclopedia. New York: Robert Appleton Company. 1913.