Carbol Fuchsin (ZN, Dilute) is used as solution for monochrome staining of bacteria. Carbol Fuchsin is a primary stain and is a lipid soluble phenolic compound and therefore it penetrates the waxy-cell walls. Staining by carbol fuchsin is further enhanced by heating the preparation to drive the stain into the cell. The acid-fast stain is an important differential stain for identifying the bacteria of the genus Mycobacterium .