Editing Pangenesis (section)

=== Weismann ===
[[File:Weismann's Germ Plasm.svg |thumb |[[August Weismann]]'s [[germ plasm]] theory. The hereditary material, the germ plasm, is confined to the gonads. Somatic cells (of the body) develop afresh in each generation from the germ plasm. The implied [[Weismann barrier]] between the germ line and the soma prevents Lamarckian inheritance. |270x270px]]

[[August Weismann]]'s idea, set out in his 1892 book ''Das Keimplasma: eine Theorie der Vererbung'' (The Germ Plasm: a Theory of Inheritance),<ref>{{cite book |url=http://www.deutschestextarchiv.de/book/show/weismann_keimplasma_1892 |title=Das Keimplasma: eine Theorie der Vererbung |author=Weismann, August |date=1892 |publisher=Fischer |location=Jena |trans-title=The Germ Plasm: A theory of inheritance}}</ref> was that the hereditary material, which he called the [[germ plasm]], and the rest of the body (the [[Somatic (biology)|soma]]) had a one-way relationship: the germ-plasm formed the body, but the body did not influence the germ-plasm, except indirectly in its participation in a population subject to natural selection. This distinction is commonly referred to as the [[Weismann barrier|Weismann Barrier]]. If correct, this made Darwin's pangenesis wrong and Lamarckian inheritance impossible. His experiment on mice, cutting off their tails and showing that their offspring had normal tails across multiple generations, was proposed as a proof of the non-existence of Lamarckian inheritance, although Peter Gauthier has argued that [[Weismann's experiment]] showed only that injury did not affect the germ plasm and neglected to test the effect of Lamarckian use and disuse.<ref>{{cite journal |last=Gauthier |first=Peter |date=March–May 1990 |title=Does Weismann's Experiment Constitute a Refutation of the Lamarckian Hypothesis? |journal=BIOS |volume=61 |pages=6–8 |jstor=4608123 |number=1/2}}</ref> Weismann argued strongly and dogmatically for Darwinism and against neo-Lamarckism, polarising opinions among other scientists.<ref name=":6">{{Cite book |title=Neo-Lamarckism and the evolution controversy in France, 1870-1920 |author=Persell, Stuart Michael |date=1999 |publisher=Edwin Mellen Press |isbn=978-0773482753 |location=Lewiston, NY |oclc=40193707}}</ref> This increased anti-Darwinian feeling, contributing to [[Eclipse of Darwinism|its eclipse]].<ref>{{cite book |title=Evolution: The History of an Idea |last=Bowler |first=Peter J. |publisher=[[University of California Press]] |year=2003 |isbn=978-0-520-23693-6 |edition=3rd completely rev. and expanded |location=Berkeley, CA |pages=[https://archive.org/details/evolutionhistory0000bowl_n7y8/page/253 253–256] |author-link=Peter J. Bowler |url=https://archive.org/details/evolutionhistory0000bowl_n7y8/page/253}}</ref><ref>{{cite book |title=Evolution: The History of an Idea |last=Bowler |first=Peter J. |publisher=[[University of California Press]] |year=1989 |isbn=978-0-520-06386-0 |edition=2nd revised |location=Berkeley, CA |pages=[https://archive.org/details/evolutionhistory0000bowl/page/247 247–253, 257] |author-link=Peter J. Bowler |url=https://archive.org/details/evolutionhistory0000bowl/page/247}}</ref>