Schwann, Theodor

Schwann, Theodor (tā`ōdōr shvän), 1810–82, German physiologist and histologist. He was a student of J. P. Müller and professor at the universities of Louvain (1838–48) and Liège (from 1848). A cofounder (with Matthias Schleiden) of the cell theory, Schwann extended the work of Schleiden and demonstrated that the cell is the basis of animal as well as of plant tissue, and because he recognized the physiological and the morphological significance of the cell in advance of other 19th-century biologists he may be called the father of cytology. He described the nerve sheath known by his name and demonstrated the living nature of yeasts. Of great influence was his Microscopical Researches … in the Structure and Growth of Animals and Plants (1839, tr. 1847).

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Schwann, Theodor

(born Dec. 7, 1810, Neuss, Prussia—died Jan. 11, 1882, Cologne, Ger.) German physiologist. He founded modern histology by recognizing the cell as the basic unit of animal structure. A year after Mathias Jacob Schleiden, a colleague Schwann knew well, advanced the cell theory for plants, Schwann extended it to animals. While investigating digestive processes, he isolated a substance responsible for digestion in the stomach, the first enzyme prepared from animal tissue, and named it pepsin. He studied muscle contraction and nerve structure, discovering the striated muscle in the upper esophagus and the myelin sheath covering nerve cells. He coined the term metabolism, identified the role played by microorganisms in the decomposition of organic matter, and formulated the basic principles of embryology by observing that the egg is a single cell that eventually develops into a complete organism.

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Schwann, Theodor 

Born Dec. 7, 1810, in Neuss; died Jan. 14, 1882, in Cologne. German physiologist and histologist; creator of the cell theory (seeCELL THEORY).

After graduating from the medical faculty of the University of Berlin in 1834, Schwann worked under Johannes Müller in the anatomical museum of the University of Berlin from 1834 to 1839. He was a professor at the universities of Louvain (1839–47) and Liége (1848–80) in Belgium.

Schwann conducted research in various fields of biology. He investigated the effects of oxygen on the development of avian eggs and the process of putrefaction and established the involvement of yeast fungi in fermentation. In 1836 he discovered the digestive enzyme pepsin. He also studied the microscopic structure of chorda and cartilage in amphibian larvae. Schwann was acquainted with the work of the German botanist M. Schleiden on the function of the nucleus in the plant cell (already fairly well studied by that time) and concluded after comparing Schleiden’s findings with his own that the structure and development of plants and animals from cells is based on the same principle. In 1838 he published three preliminary reports, and in 1839, his classic work, whose very title reflects the essence of the cell theory: Mikroskopische Untersuchungen über die Uebereinstimmung in der Struktur und dem Wachstum der Tiere und Pftanzen (Microscopic Researches on the Similarity in Structure and Growth in Animals and Plants). According to F. Engels, the creation of the cell theory, along with the law of the transformation of energy and the theory of evolution, was one of the three greatest discoveries in natural science in the 19th century.

Schwann was a fellow of the Royal Society of London (1879), the Paris Academy of Sciences (1879), and the Academy of Sciences in Brussels (1841).

WORKS

In Russian translation:
Mikroscopicheskie issledovaniia o sootvetstvii v strukture i roste zhivotnykh i rastenii. Moscow-Leningrad, 1939.

REFERENCES

Katsnel’son, Z. S. “Teodor Shvann i sovremennaia kletochnaia teoriia.” Izv. AN SSSR: Seriia biologicheskaia, 1957, no. 4.
Katsnel’son, Z. S. Kletochnaia teoriia v ee istoricheskom razvitii. Leningrad, 1963.

Z. S. KATSNEL’SON