Methylene Blue was earlier recognized as a good nuclear stain, the staining solutions are always either aged or alkalized, if not both. More importantly it is an excellent stain for ribonucleic acid, which is the important stainable constituent of bacterial bodies, of lymphocyte and hemoportoal cytoplasm, and of nerve cell tigroid granules. It can also be employed in capsule stain. The capsule stain begins as a negative stain leaving the organisms colorless. The capsule are clearly seen as halo surrounding the bacterial cell. Another staining procedure is performed with nigrosin (Cat. No. 43925).

reagent contains:
methylene blue 0.5 g
distilled water 100 ml