DIFFERENTIAL STAINING OF NERVE-CELLS AND FIBERS FOR SECTIONS OF PARAFFIN-EMBEDDED MATERIAL IN MAMMALIAN CENTRAL-NERVOUS-SYSTEM

A differential staining method is described of myelinated fibres and n erve cell bodies applicable to sections of mammalian, including human, central nervous system specimens embedded in paraffin wax. Experiment al and human necropsy material fixed in acetic pa raformaldehyde in ph osphate buffer was used. Sections of 15-20 mu m in thickness were obta ined, attached to slides, deparaffinized and hydrated. After hydration , sections are oxidized (30 s) in 2% potassium permanganate, bleached (1 min) in 5% oxalic acid and rinsed in distilled water. Staining is f or 2-5 h in the following solution: 0.06% thionin, 1% formaldehyde, 10 % acetic acid in distilled water. Sections are subsequently washed in distilled water, dehydrated through 96% and absolute ethanol, cleared in eucalyptol and mounted in Eukitt. Using the method described in the present paper, a differential coloration of myelin and neurons is obt ained. Myelinated fibres appear red, whereas nerve cell bodies and gli al nuclei are stained blue. This procedure provides a high contrast be tween myelin and cells suitable for observation and photography of sec tions. Simultaneous and differential coloration of both myelin and cel ls is easily and directly obtained with constant and homogeneous resul ts.