Elected For.Mem.R.S. 1952
During the past few decades, developmental biology has become one of the most exciting areas of science. This is largely a result of the rapidly growing knowledge of molecular biology, partly resulting from the achievements of earlier generations of embryologists. One of the men of special importance among the embryologists of the twentieth century was Sven Hörstadius. Most of the content in today's biology textbooks describes results from the post – Watson–Crick era. However, few texts exclude figures and facts from Sven Hörstadius's dissertation of exactly seventy years ago. His experiments on sea urchin larvae shed light on a couple of the most central findings in developmental biology, namely that the uneven distribution of the egg–cell contents gives rise to early embryo cells with shifting qualities, and that communication between these cells has an essential role in the differentiation process. In the same way, his achievements on the neural crest and its impact on head development in vertebrates have been of lasting importance.