Procion brilliant orange, a counterstain for decalcified sections vitally labeled with procion brilliant red H-8 bs

Procion brilliant red H-8 BS is a fluorescent dye that stains the organic matrix of bone supravitally. A procedure is described for counterstaining sections of such bone for visible light examination without interfering with the demonstration of sites of bound dye under UV illumination. Sections are brought to water, stained in Delafield's alum hematoxylin for 10 minutes, washed in tap water for 10 minutes, counterstained in 1% Procion brillant orange M-GS for 15 minutes and washed in distilled water for 10 minutes. After dehydration the sections were mounted in Eukitt.