The German chemist Richard Willstatter, 1872-1942. He studied chemistry at the University of Munich and in 1905 obtained a professorship at the University of Zurich until 1925. Willstatter, using the chromatographic technique developed by the Russian botanist Tswett (1872- 1920), showed that the molecules of chlorophyll contain a single atom of magnesium. He also showed the similarity between the magnesium and the iron atom in the molecule of haemoglobin. In 1915 he was awarded the Nobel Prize in chemistry for his work on chlorophyll. Willstatter, who was Jewish, spent the last part of his life in continuous danger and in 1939 he migrated to Switzerland.