Which staining method uses Chronic acid and Metanil Yellow as reagents?

• A. Gridley
• B. Grocott
• C. Gram stain
• D. Ziehl-Neelsen

Answer: (A)

Reagent pairing is what distinguishes a staining method. Chromic acid acts as an oxidative mordant that prepares tissue components to take up a secondary dye, and Metanil Yellow then provides a distinctive yellow counterstain in the Gridley technique. This specific combination—chromic acid with Metanil Yellow—is characteristic of the Gridley staining method, helping to differentiate certain tissue elements in a way that the other options do not. The Gram stain relies on crystal violet, iodine, alcohol decolorization, and a safranin counterstain; Ziehl-Neelsen uses carbol fuchsin with an acid-alcohol decolorizer; and Grocott’s method uses silver-based impregnation with a contrasting counterstain. Thus, the reagents described point to Gridley.