[The different procedures for value collection in biological morphometry and stereology (author's transl)].

Each stereological or morphometrical investigation presumes a high experience in structure diagnosis. Therefore, a good contrast between the structures to be evaluated is necessary, especially when using automatic measuring systems. Furthermore, some suggestions are given to facilitate the object-evaluation. The stereological principles including pattern-recognition are mentioned briefly in order to understand some of the technical details. The techniques are divided into simple and advanced procedures. However, it is also possible to evaluate using a simple counter combined off- or on-line with a computer. The advanced system can be divided into tracing instruments and photometric- and television-scanning procedures. The first system which is manipulated by eye-control can also be called "optomanual devices". These are planimetry, a type of automatic point counting, and instruments which locate the coordinates by ultrasound or a magnetic tableau. With relatively inexpensive electronics the coordinates can be transformed into stereological values. The photometric instruments and the television devices "Scan-computers" discriminate only between gray-steps while measuring. The first group works by moving either the photometric spot (flying spot) or the microscopical object-stage. The second group is guided by its computer and the output immediately shows the stereological results. The discussion gives information about choosing the best instrument for investigation. The scientist should keep in mind that the size of the over-all procedure, the frequency of measuring, the time of object preparation, the possible difficulty in discrimination of the gray-steps and the extent of his scientific funds are important for his decision.