The discovery of x rays, which Kölliker later renamed “Roentgen rays”; the foundation stone of the science of roentgenology. For his work, Röntgen was awarded the first Nobel Prize for Physics in 1901. English translation in Nature, (February,) 1896, 53, 274 and 377. See also Röntgen’s third paper on the subject: Weitere Beobachtungen über die Eigenschaften der X-Strahlen. Sitzber. K. Preuss. Akad. Wiss., Ber., Kl. Phys.-Math., 1897, 576-592. Facsimile reprint of all three papers, English translation, and bibliography in H. Klickstein, Wilhelm Conrad Röntgen on a new kind of rays. A bibliographical study, 2 vols., 1966.