Name a hematoxylin that is not readily decolorized with acidic solutions.

• A. Weigerts
• B. Gill
• C. Mallory
• D. Delafield

Answer: (A)

The main idea here is how stable hematoxylin-nuclear staining is to acid differentiation. When hematoxylin forms a complex with a mordant, its resistance to acid alcohol depends on that mordant. Weigert’s hematoxylin uses an iron mordant to form a ferric-hematoxylin complex that binds very strongly to tissue and resists removal by acid solutions. This means it is not readily decolorized during acidic differentiation steps, so the nuclear stain remains robust. The other formulations—Gill, Mallory, and Delafield hematoxylins—produce complexes that are more susceptible to acid decolorization, so they fade more easily under acidic differentiation. Therefore, Weigert’s hematoxylin is the one not readily decolorized with acidic solutions.