Formalin pigment can be removed from tissue by immersion in alcoholic picric acid.

• A. True
• B. False
• C. Both
• D. Neither

Answer: (A)

Formalin pigment is a brownish byproduct that can form in tissue fixed with formalin and can be mistaken for other pigments. Immersion in alcoholic picric acid dissolves this pigment because the pigment forms a complex that is soluble in the alcohol-picric acid solution. The combination provides both solvent and the acidic environment needed to break down the pigment without severely affecting the rest of the stain, making it a reliable way to prevent misinterpretation. So, this method is true for removing formalin pigment.