Which fixative increases acidophilia and basophilia of the tissue?

• A. Mercury fixative
• B. Alcohol
• C. Formalin
• D. Acetic acid

Answer: (A)

Staining properties depend on how a fixative preserves and alters tissue proteins before staining. Mercury-containing fixatives coagulate and cross-link proteins very aggressively, which stabilizes both cytoplasmic components that eosin (acidophilic dye) binds and nuclear/basophilic structures that hematoxylin binds. This strong, broad preservation tends to amplify both acidophilia and basophilia, giving the tissue a more vivid appearance with H&E.

Other fixatives modify staining in different ways and don’t produce that same dual enhancement. For example, alcohol and acetic acid act mainly through dehydration or swelling and can shift staining in less consistent ways, while formalin cross-links tissues enough to preserve morphology but doesn't typically maximize both acidophilic and basophilic staining to the same extent as mercury fixatives.