Perls-Van Gieson kit is used for staining free iron ferric ions and connective tissue. Fuchsin Acid Van Gieson is a component of the kit and it contains two dyes (acid fuchsin, picric acid) that simultaneously stain different tissue structures. Acid fuchsin stains collagen fibers intensive red while picric acid stains muscle fibers, erythrocytes and glial fibers yellow. Amyloids, hyalin, colloid and mucosa are stained in nuances between red and yellow. Potassium hexacyanoferrate solution reacts in presence of iron and creates non-soluble blue dye precipitate.