Changing development by microsurgery
Trained at Würzburg, Spemann became a professor at Freiburg in 1919. The relatively large eggs and embryos of amphibians supported fine manipulations. Transplanting tissues or dividing embryos allowed him to examine development under altered conditions.
References: [1]
The experiments with Mangold
In Spemann’s laboratory, Mangold transplanted newt dorsal blastopore-lip tissue to another embryo and induced an additional body axis. Differences in natural pigmentation showed that neighbouring host cells contributed to the new structures. Their findings were published together in 1924.
Investigating embryonic induction
Spemann called regions capable of organizing surrounding development organizers and compared the effects of different transplanted regions. He received the 1935 Nobel Prize in Physiology or Medicine and summarized developmental and induction studies in Embryonic Development and Induction in 1938.
References: [1]