DEVRIES, HUGO Dutch botanist, was born at Haarlem, on Feb. 16, 1848, and educated at Leyden, Heidelberg and Wurzburg. In 1871 he became a lecturer at the University of Amsterdam and in 1881 a professor. His attention was drawn to botany and to evolution by discovering on a field trip some new forms growing among a display of Oenothera, a plant that had been introduced from America. This suggested to him a new method of studying evolution, namely the experimental method rather than the old method of observation and inference. This method of investigating evolution may be regarded as his greatest contribution to science. It resulted in a new epoch in the history of evolution. He discovered in his cultures of Oenothera new forms appearing among the hosts of ordinary forms, and this method of producing new forms was named mutation (q.v.), as distinct from Darwin's natural selection. He showed that while species vary through natural selection, new species and varieties arise suddenly through mutation. In connection with his experi mental work on the mutations of Oenothera, he visited the United States, to investigate the behaviour of this plant in its natural environment. After his retirement from the university of Amster dam he made his residence in Lunteren, where he continued his experimental work in producing new forms through many genera tions of culture. His best known works are Intracellular Pangensis (1889) ; The Mutation, Theory (19o1) ; and Plant Breeding (Chicago, 1907).