A set of two stains that are used to stain (crystal violet and iodine) and counterstain (fuchsin) bacteria. @G02680@-negative bacteria are completely decolorized after treating the stained bacteria with ethanol or acetone and can be visualized by the counterstain. They have a complex cell wall in which the @P04480@ layer is covered by @L03574@ in an outer @MT06878@ structure. @G02680@-positive bacteria resist decolorization by ethanol or acetone, they retain the initial @G02680@ stain. They have a cell wall consisting predominantly of @P04480@ not overlayed by an outer @MT06878@.