The latter is utilized to stain peripheral blood smears. The giemsa stain can be helpful for identifying components in a variety of tissues. One property of methylene blue and toluidine blue dyes is metachromasia. This means that a tissue component stains a different color than the dye itself. For example, mast cell graules, cartilage, mucin, and amyloid will stain purple and not blue, which is helpful in identifying these components.
Colonies appear as fuzzy blue clusters.
Tissue gram stains are all basically the same as that used in the microbiology lab except that neutral red is used instead of safranin. The most sensitive method for demonstrating them is Methenamine silver. Spirochetes are very difficult to stain. The best method is the Warthin-Starry. A Giemsa stain may help demonstrate donovan bodies and leishmania.