<P> His germ plasm theory states that multicellular organisms consist of germ cells containing heritable information, and somatic cells that carry out ordinary bodily functions . The germ cells are influenced neither by environmental influences nor by learning or morphological changes that happen during the lifetime of an organism, which information is lost after each generation . The concept as he proposed it was referred to as Weismannism in his day, for example in the book An examination of Weismannism by George Romanes This idea was illuminated and explained by the rediscovery of Gregor Mendel's work in the early years of the 20th century (see Mendelian inheritance). </P> <P> The idea that germline cells contain information that passes to each generation unaffected by experience and independent of the somatic (body) cells, came to be referred to as the Weismann barrier, and is frequently quoted as putting a final end to the theory of Lamarck and the inheritance of acquired characteristics . What Lamarck claimed was the inheritance of characteristics acquired through effort, or will . </P> <P> Weismann conducted the experiment of removing the tails of 68 white mice, repeatedly over 5 generations, and reporting that no mice were born in consequence without a tail or even with a shorter tail . He stated that "901 young were produced by five generations of artificially mutilated parents, and yet there was not a single example of a rudimentary tail or of any other abnormality in this organ ." Weismann was aware of the limitations of this experiment, and made it clear that he embarked on the experiment precisely because, at the time, there were many claims of animals inheriting mutilations (he refers to a claim regarding a cat that had lost its tail having numerous tail-less offspring). There were also claims of Jews born without foreskins . None of these claims, he said, were backed up by reliable evidence that the parent had in fact been mutilated, leaving the perfectly plausible possibility that the modified offspring were the result of a mutated gene . The purpose of his experiment was to lay the claims of inherited mutilation to rest . The results were consistent with Weismann's germ plasm theory . </P> <P> He was awarded the Linnean Society of London's Darwin - Wallace Medal in 1908 . </P>

Who disproved the idea of inheritance using tailless mice