protoplasm, term once used for the fundamental material of which all living things were thought to be composed. It was studied by a number of early scientists, especially by Félix Dujardin, J. E. Purkinje, M. J. S. Schultze, and Hugo von Mohl (who is credited with introducing the name), all working in the 19th cent. Many of the notions associated with the term have survived. Thus it is still accepted that all living organisms are made largely of the same classes of substances such as salts and organic molecules, that some of these are organized into structures large enough to be seen in the microscope and that water almost always is by far the most abundant material. However, the term is rarely used any more in a strictly scientific sense, although it survives in more literary usages. The unity of living matter is now most often described in terms of the cell as the unit of all living organisms (viruses, which are noncellular are at the border of life, being unable to reproduce independently outside living cells) and of the ubiquity of key biochemical molecules, especially nucleic acids and proteins.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on protoplasm from Fact Monster:

  • cytoplasm - cytoplasm: cytoplasm: see protoplasm.
  • Félix Dujardin - Dujardin, Félix Dujardin, Félix , 1801–60, French zoologist. He did valuable ...
  • Max Johann Sigismund Schultze - Schultze, Max Johann Sigismund Schultze, Max Johann Sigismund , 1825–74, German biologist, ...
  • Hugo von Mohl - Mohl, Hugo von Mohl, Hugo von , 1805–72, German botanist. He is noted for his research on the ...
  • Karl Wilhelm von Nägeli - Nägeli or Naegeli, Karl Wilhelm von Nägeli or Naegeli, Karl Wilhelm von , 1817–91, ...

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