Theodor Schwann

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For the American Union Army officer, see Theodore Schwan.
Theodor Schwann
Theodor Schwann Litho.jpg
Theodor Schwann
Born (1810-12-07)7 December 1810
Neuss, First French Empire (now in Germany)
Died 11 January 1882(1882-01-11) (aged 71)
Cologne, German Empire
Known for Cell theory
Schwann cells
Influences Johannes Peter Müller

Theodor Schwann (7 December 1810 – 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[edit]

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 physiologist Johannes Peter Müller.[1]

Contributions[edit]

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 their different properties. Schwann found particular interest in the nervous and muscular tissues. He discovered the cells which envelope the nerve fibers, now called Schwann cells in his honor.

Schwann discovered the striated muscle in the upper esophagus and initiated research into muscle contraction, since expanded upon greatly by Emil du Bois-Reymond and others. Müller directed Schwann's attention to the process of digestion, and in 1837 Schwann isolated an enzyme essential to digestion, which he called pepsin.[1]

In his later years, Schwann found growing interest in theological issues. Schwann died in Cologne on 11 January 1882.

Cell theory[edit]

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".[2] This became cell theory or cell doctrine.

In the course of his verification of cell theory, Schwann proved the cellular origin and development of the most highly differentiated tissues including nails, feathers, and tooth enamel. Schwann established a basic principle of embryology by observing that the ovum is a single cell that eventually develops into a complete organism.

Schwann's theory and observations became the foundation of modern histology. In 1857, pathologist Rudolf Virchow posed the maxim Omnis cellula e cellula—that every cell arises from another cell. By the 1860s, cell doctrine became the conventional view of the elementary anatomical composition of plants and animals. Schwann's theory and observations became the foundation of modern histology.[1]

Vitalism and germ theory[edit]

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 disconfirmation. In the early 1840s, Schwann went beyond others who had noted simply the multiplication of yeast during alcoholic fermentation, as Schwann assigned the yeast the role of primary causal factor, and then went further and claimed it was alive. Embattled controversy ensued as eminent chemists alleged that Schwann was undoing scientific progress by reverting to vitalism.[citation needed]

After publishing anonymous mockery in a journal of their own editorship,[Who published the mockery? clarification needed] they published a purely physicochemical if also hypothetical explanation of the interaction resulting in fermentation. As both the rival perspectives were hypothetical, and there was not even an empirical definition of 'life' to hold as a reference frame, the controversy—as well as interest itself—fell into obscurity unresolved. Pasteur began fermentation researches in 1857 by approximately just repeating and confirming Schwann's, yet Pasteur accepted that yeast were alive, thus dissolving the controversy over their living status, and then Pasteur took fermentation researches further.[citation needed]

In retrospect, the germ theory of Pasteur, as well as its antiseptic applications by Lister, can be traced to Schwann's influence.[1]

References[edit]

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

  1. ^ a b c d Chisholm 1911.
  2. ^ Schwann, Theodor (1839). Microscopic Investigations on the Accordance in the Structure and Growth of Plants and Animals. Berlin.  (English translation by the Sydenham Society, 1847)

Further reading[edit]

  • Aszmann, O. C. (2000). "The life and work of Theodore Schwann". Journal of reconstructive microsurgery 16 (4): 291–5. doi:10.1055/s-2000-7336. PMID 10871087. 
  • Florkin, M. (1958). "Episodes in medicine of the people from Liège: Schwann & the stigmatized". Revue médicale de Liège 13 (18): 627–38. PMID 13591909. 
  • Florkin, M. (1957). "1838; Year of crisis in the life of Théodore Schwann". Revue médicale de Liège 12 (18): 503–10. PMID 13466730. 
  • Florkin, M. (1957). "Discovery of pepsin by Theodor Schwann". Revue médicale de Liège 12 (5): 139–44. PMID 13432398. 
  • Florkin, M. (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. PMID 14883601. 
  • Florkin, M. (1951). "The family and childhood of Schwann". Revue médicale de Liège 6 (9). PMID 14845235. 
  • Lukács, D. (April 1982). "Centenary of the death of Theodor Schwann". Orvosi hetilap 123 (14): 864–6. PMID 7043357. 
  • Watermann, R. (1973). "Theodor Schwann accepted the honorable appointment abroad". Medizinische Monatsschrift (Germany, West) 27 (1): 28–31. PMID 4576700. 
  • Watermann, R. (1960). "Theodor Schwann as a maker of lifesaving apparatus". Die Medizinische Welt 50: 2682–7. PMID 13783359. 

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