Wright’s stain is used for the differential staining of blood smears and bone marrow aspirates. Most commercially available products also contain Giemsa stain which intensifies the staining. Traditional Wright’s stain is a solution of lightly oxidized methylene blue in methanol. The oxidation produces a mixture of methylene blue, azure A, azure B, azure C and thionin. The mixture of dyes gives the results a polychroming effect which enhances the differentiation of the white cells. The staining procedure is a two-step procedure that requires the addition of a buffer during staining (Giordano buffer, catalog # 593A). These items are manufactured in the United States by Medical Chemical Corp