215 years ago today, on December 7, 1810 (November 11, 1810), German physiologist Sodo Schwann was born. Schwann Theodor was born in Noyes on December 7, 1810 and died in Cologne on January 11, 1882. German physiologist, one of the founders of the cytology theory, is generally regarded as the founder of modern histology (the study of the tissue structure of animals and plants). Schwann was taught at the Universities of Bonn, Würzburg and Berlin, where he received his MD in 1834. From 1834 he worked with Johannes Peter Muller until 1838 when he moved to Belgium. He was professor of anatomy at the University of Louvain (1838-1847) and then in Liege until his death. Schwann's first experiment in Berlin was the problem of muscle contraction. He proposed that mechanical contraction could be explained by no dynamism at all - a point contrary to Miller's teachings. This mechanistic philosophy was later developed productively by his successors in Berlin, Emil du Bois-Reymond and Hermann von Helmholtz. Schwann also conducted some experiments to overturn the naturalistic view that had resurrected in the mid-1030s. In 1836, he accidentally discovered that fermentation required the involvement of yeast in his experiments on corruption and fermentation, and Charles Canal. CharlesCagniarddelaTOur also independently discovered this problem. In the same year Schwann also discovered digestive enzymes (pepsin). Of course, Schwann's most memorable achievement and most important work is his Microscopic Studies, or Microscopic Studies of the Consistency of Structure and Growth in Animals and Plants (Mikiosko-pischeUntersuchungen; Mic-roscopicalResearches, 1839). In this book, for the first time, the most important of all ideas in modern biology was systematically stated: that animals and plants are composed of cells. At the same time, Mat-thias Schleiden also proposed that "the structure of cells may be quite widespread, and may be a general principle for the construction of all organic matter." In 1838 Schleiden proposed that all plant tissues are composed of nucleated cells. Using the newly introduced achromatic microscope, Schwann continued to study tissues taken from several different animals. He hypothesized that fibrous ducts and the like were not composed directly of molecules, but of cells. He regarded the process of cell formation as somewhat like crystallization. Cells are not formed by other cells, but by the agglutination of the intercellular fluid "nutrient solution". He was even more mistaken in his belief that cellular matter, the Schwann cytoblastema, was unstructured. Despite these errors, the cell theory was quickly accepted. And it was soon corrected. In 1841 Robert Remak was the first to describe cell division, and in 1855 Rudolf Virchow was able to present his new dogma: "All cells are derived from cells." The idea of the embryonic basis of the cell was of course modified and renamed protoplasm, and in 1861 Max Schultz proved that it had a definite character and structure. Despite these achievements, Schwann's fermentation results were rudely criticized by chemical authorities of the time, such as Jus-tusvon Liebig and Friedrich Wohler. Especially after the two published a vicious attack in 1830, Schwann felt it impossible to continue working in Germany. He carried out his professional duties cautiously in Belgium and invented some devices that benefited the mining industry. However, his most outstanding contributions to physiology actually ended, and it was not until Pasteur's findings were published in the 1860s that Schwann was proved correct. Comments: One of the founders of the cell theory