SCIENCE PHOTO LIBRARY SCIENCE PHOTO LIBRARY
Portrait of August Weismann (1834-1914), German biologist. Weismann spent a few years practising medicine before entering research. He became a teacher at the University of Freiburg, and was forced to be a theorist by failing eyesight. He worked in heredity, proposing that all organisms contain a 'germ plasm'. He later identified this with the chromosomes of the cell nucleus. He proposed that in reproduction the chromosome number was halved by division, then two halves, one from each parent, united. He saw this as the basis of variability. Although broadly correct, Weismann also believed that the chromosomes were immune to outside influence, which they are not.
Model release not available. Property release not required.