- A dictionary of medical eponyms

Semon-Hering theory (Karl Ewald Konstantin Hering)

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The theory that stimuli leave definite traces (engrams) on the protoplasm of the animal or plant. When these stimuli are regularly repeated they induce a habit which persists after the stimuli cease, and these acquired habits may thus be transmitted to the descendants.

This is basically the same as Lamarckism, the theory that acquired traits are inheritable and that evolutionary changes are the result of environmental changes. The correct theory, that acquired characteristics are not inherited, is known as Weismannism,

Lamarckism and Weismannism are named for the French natural scientist Jean-Baptiste-Pierre-Antoine de Monet, chevalier de Lamarck (1744-1829) and the German biologist and geneticist August Friedrich Leopold Weismann (1834-1914).


  • Jean Baptiste Lamarck:
    Philosophie zoologique. 2 volumes; Paris, 1809.
  • K. E. K. Hering:
    Ueber das Gedächtnis als eine allgemeine Function der organisirten Materie.
    Vortrag. Kaiserliche Akademie der Wissenschaften Wien, 30. Mai, 1870. Wien, 1870.
    A first edition of this book is an extremely rare collector's item.
  • August Weismann:
    Das Keimplasma. Eine Theorie der Vererbung. Jena, G. Fischer, 1892. XVIII + 628 pages.
    The theory that all heritable characteristics arise in the germ plasm and that acquired characteristics cannot be inherited.
  • R. Semon:
    Die Mnemische Empfindungen in ihren Beziehungen zu den Originalempfindungen.
    1909. 2nd edition, Leipzig: Verlag von Wilhelm Engelmann, 1922.
  • R. Semon:
    Das Problem der Vererbung "erworbener Eigenschaften".
    Leipzig: Verlag von Wilhelm Engelmann, 1912. viii + 203 pages.
    In this book Semon proposes a theory entirely based on the heredity of acquired characters.
  • R. Semon:
    The Mneme.
    English translation, London, 1908, 1911 and 1921. First German edition 1904.
  • Jürgen Schatzmann:
    Richard Semon (1859 – 1918) und seine Mnemetheorie. 1968, 100 pages.
We thank Rudolf Kleinert, Bad Reichenhall, Germany, for information submitted.

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