Weismann, August, VYS mahn, OW gust (1834-1914), a German biologist, is known chiefly for his theories of heredity and evolution. He stressed the independence from the rest of the body of the germ plasm, his name for the factors of inheritance in the sex cells. He denied that acquired characteristics can be inherited. He located the germ plasm in the chromosomes, a prediction that was proved correct early in the 1900's. Weismann upheld the theory of natural selection and was one of the first German scientists to support the British scientist Charles Darwin.