Improved silver technique for showing nucleolar organiser regions in paraffin wax sections

An improved technique for the demonstration of nucleolar organiser regions (NORs) was devised. It has the advantage that any non-specific background deposits which mimic the NOR dots formed during staining are trapped by the celloidin film. The specificity of the silver staining is also increased by the postfixation treatment of sections in an acetic acid-ethanol mixture. Moreover, it is economical because of the low silver content and small volume of the incubation solution used.