Spemann, Hans (1869-1941) was a German biologist and a pioneer in the field of experimental embryology. He received the 1935 Nobel Prize in physiology or medicine for his discoveries regarding the development process of embryos. His breakthrough concept of “embryological induction” contributed to the establishment of the school of developmental biology.

Spemann received a Ph.D. degree in zoology, botany, and physics in 1895, from the University of Wurzburg, and then continued to work there as a teacher until 1908. There, his scientific interests were greatly influenced by his work under the renowned embryologist Theodor Boveri and physicist Wilhelm Conrad Roentgen. In 1919, he accepted the post of professor of zoology at the University of Freiburg. He remained on the faculty there until his retirement in 1935.

Spemann's study of embryology began with experiments on amphibian embryos. He succeeded in splitting a newly laid salamander egg and from each half a normal salamander embryo developed. With further research, he correctly concluded that at some point an embryo's cells begin to differentiate. Working with his students Otto Mangold and Hilde Mangold, Spemann discovered that when a specific type of tissue of an embryo was transplanted onto a different kind of tissue within the embryo, the transplanted tissue tended to develop into the type of tissue where it had been transplanted. Based on this induced action, Spemann described embryos as having various “organizers” or “organizing centers,” which guide the development of the cells as necessary. His discoveries also led him to predict the possibility of cloning differentiated or even adult cells, though there was no technology to do so at the time.