<P> August Friedrich Leopold Weismann ( 17 January 1834 -- 5 November 1914 ) was a German evolutionary biologist . Ernst Mayr ranked him as the second most notable evolutionary theorist of the 19th century , after Charles Darwin . Weismann became the Director of the Zoological Institute and the first Professor of Zoology at Freiburg . </P>
who refuted the theory of pangenesis with his classic experiment on mice tails
August Friedrich Leopold Weismann