Spemann, Hans (1869–1941)

German embryologist who was awarded a Nobel Prize for Physiology or Medicine in 1935 for his work on the organizer effect in embryonic development. He discovered the phenomenon of embryonic induction – the influence exerted by various regions of an embryo that controls the development of cells into specific organs and tissues.

Spemann was born in Stuttgart and studied at Heidelberg and Würtzburg. In 1908 he was appointed professor at Rostock.

He was director of the Kaiser Wilhelm Institute of Biology in Berlin in 1914–19, and professor at Freiburg im Breisgau in 1919–35.

Spemann carried out his research on newt embryos. He found that embryos split in half at an early stage of development either died or developed into a whole embryo, but if they were divided at a later stage, half-embryos formed. Next he transplanted various embryonic parts to other areas of the embryo and to different embryos, and demonstrated that one area of embryonic tissue influences the development of neighbouring tissues.

In another series of experiments, Spemann found that embryonic tissue from newts always gives rise to newt organs, even when transplanted into a frog embryo, and that frog tissue always develops into frog organs in a newt embryo.

In the course of this work, Spemann pioneered techniques of microsurgery.