Used in microbiology to visualize bacterial capsules, which are gelatinous outer layers surrounding certain bacteria. The stain helps differentiate encapsulated bacteria from non-encapsulated ones under the microscope. Capsule staining is important in identifying pathogenic bacteria, such as Streptococcus pneumoniae and Klebsiella pneumoniae, because the presence of a capsule often correlates with virulence. The technique uses a negative staining method where the background is stained, leaving the capsule clear and visible as a halo around the cell. This aids in bacterial classification and supports diagnostic procedures in clinical laboratories.