The Gram Stain Kit is intended for the demonstration and differentiation of Gram-positive and Gram-negative bacteria. Gram Positive Bacteria: Blue Gram Negative Bacteria: Red Other Tissue: Yellow Nuclei: Red The Giemsa Stain Kit (May-Grunwald) is intended for use in the visualization of cells present in hematopoietic tissues and certain microorganisms. This kit may be used on formalin-fixed, paraffin-embedded or frozen sections. Nuclei: Blue/Violet Cytoplasm: Light Blue Collagen: Pale Pink Muscle Fibers: Pale Pink Erythrocytes: Gray, Yellow or Pink Rickettsia: Reddish-Purple Helicobacter Pylori: Blue Mast Cells: Dark Blue with Red Granules Source : Scytek Laboratories