Spemann, << SHPAY mahn, >> Hans (1869-1941), a German biologist, pioneered in the analysis of embryonic development. Through novel, delicate grafting experiments performed on frog and newt embryos, Spemann discovered organizers. These are organ-forming influences exerted on tissues by neighboring embryo parts. He showed that the lens of the eye, for example, is induced to develop by the underlying eye-cup. He won the 1935 Nobel Prize for physiology or medicine. Spemann was born in Stuttgart.
