[Spot marking of photo-optic preparations intended for ultratomy].

The possibility of a highly precise spot marking of those areas of the tissue which are of interest for the investigator of the group and individual cells revealed during the photo-optic investigation of preparations, is of particular importance for their subsequent ultrastructural studies. However, the markers used new for marking photo-optic preparations, whose effect is based on the principle of delineation and of the area concerned, suffer a number of shortcomings, one of them being the impossibility to variate while marking the geometrical form of the mark on the preparation and to apply to it simultaneously more than one mark. In combined photo-optic and electron-microscopy studies of preparations it would be invaluable to apply a highly precise spot marker capable of applying simultaneously to the preparation two marks differing from each other by their geometrical form. In this case, the process of formation of "pyramid" would have been considerably easier for the investigator during the preparation of the specimen for ultratomy. Exactly this kind of a highly precise spot universal marker based on the principle of stamping has been designed and used by the author.