Progress in science is often promoted by a new method. Diagnostic cytology, however, developed slowly over a whole century, mainly in differentiating malignant from benign cells from various tissues. The decisive step in this development was the intensive investigation of one local- ization by Papanicolaou: The application of cytology for screening in the field of gynecologic oncology made it an acknowledged technique. Consequently, materials inves- tigated before were tested again on a larger scale and new ones were included into the program. The possibility of a wide-range application of...