Well developed granules of volutin (polyphosphate) may be seen in unstained wet preparations as round refractile bodies within the bacterial cytoplasm. With basic dye, they tend to stain more strongly than the rest of the bacterium, and with toluidine blue or methylene blue they stain metachromatically, a reddish purple colour. They are demonstrated most clearly by special methods, such as Neisser's, which stain them dark purple but the remainder of the bacterium with a contrasting on a blood or serum medium. counterstain.The diphtheria bacillus gives its characteristic volutin-staining reactions best in a young culture (18-24 hours)