1. Hermann Joseph Müller (1890 - 1965) discovers X-rays to be agents of mutation.

  2. The first German Nature Conservation Day (Deutscher Naturschutztag DNT) took place in Munich from 26 July - 28 July 1925. Since 1957 the conference is held every two years.

  3. Accident insurance is extended, at first to cover 11 occupational illnesses.