Species and Varieties, Their Origin by Mutation

"Species and Varieties, Their Origin by Mutation" by Hugo de Vries is a scientific work that puts forward the idea that new kinds of plants and animals come about through big, sudden changes called mutations, instead of the slow, gradual changes that were commonly believed at the time. In his lectures, De Vries explains how he thinks these mutations are the main way new species and varieties appear. He argues that we can actually study how new species and varieties form through experiments, especially by looking at farming and gardening. The author starts off by explaining how his theory of mutation is different from the usual ideas about evolution; instead of small changes over long periods, he believes new types of organisms can pop up all at once. De Vries emphasizes doing experiments and keeping careful track of what happens to really understand how living things evolve, and he points out problems with older theories that rely too much on things changing slowly.