1894 Richard Greeff, a young scientist at the University of Berlin, translated the book "The retina of vertebrates" of Santiago Ramón y Cajal into German. Greeff himself had already applied the Golgi-Cajal-Chromic-Silver dye to the retina and was enthusiastic about the results of Cajal. He interrupted his own investigations in favour of translating the book into German. Cajal demonstrates that the retina contains individual neurons contradicting the theory at that time, that the nervous system is a synzythium. This new theory had a great impact on German science although it took years to be accepted unanimously.