Rontgen’s first communication made public the fact that X-rays excited fluorescent substances and the world’s first fluoroscope quickly followed in January 1896. It is attributed^ to the Italian scientist E. Salvioni who demonstrated his cryptoscope, Figure [10.1], before the Perugia Medical Society. It was of a very simple design: a tube having at one end a pasteboard cover coated with fine crystals of platino-barium cyanide and at the other end an eyepiece.