Mendeleyev's "periodic system of elements" clearly shows how very important in the history of nature is the emergence of qualitative changes out of quantitative changes. The same thing is shown in biology by the theory of neo-Lamarckism, to which neo-Darwinism is yielding place. (Stalin 1906, 304)More specifically, Stalin rejected the ideas of August Weismann, a 19th-century German biologist, in favor of Trofim Lysenko, a pseudoscientist who based his ideas on Lamarckism. Weismann, who accepted Darwin's theory of evolution, disproved Lamarckism and proposed that germ cells pass on hereditary information; his work was an early variant of the modern evolutionary synthesis which unites evolutionary theory with genetics. Stalin appointed Lysenko head of the Academy of Agricultural Sciences of the Soviet Union, where he had great political power. (Rossiannov 1993)