Mayer’s Hematoxylin (Lillie’s Modification) is a progressive nuclear hematoxylin stain with several histological applications. Nuclei should staining is strong, clean, crisp, and no differentiation is needed. Bluing reagent (Catalog: BRT) may be used following hematoxylin to “blue” or alter the shade of hematoxylin from a purple to blue. Nuclei: Purple. Nuclei after Bluing: Blue. Blue nuclei after Eosin: Blue to Violet.