Diapath Special Stains Kit for Perls stain to visualize reactive ferric iron on histological section. The acid potassium ferrocyanide solution reacts in presence of reactive ferric iron making an insoluble blue precipitate (Prussian blue). The Kit supplies as counterstaining the picrofuchsine acc. Van Gieson, a solution obtained by mixing two reagents: acid fuchsine, made by big molecules that penetrate and highlight collagen fibers, and picric acid, made by small molecules for the staining of collagen and muscle fibers, cytoplasm and blood cells.