Acetic acid is a useful addition to many compound fixatives because of its shrinking action.

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

Answer: (B)

The thing to understand here is how acetic acid affects tissue during fixation. Acetic acid tends to swell cells, especially the nuclei, due to its osmotic and protein-precipitating effects. It is commonly added to compound fixatives (like Carnoy’s solution, which is ethanol, chloroform, and acetic acid) to rapidly fix and preserve nuclear detail. Shrinkage, on the other hand, is more associated with dehydration methods using alcohols and organic solvents that remove water and contract the tissue. Because acetic acid promotes swelling rather than shrinking, the statement about shrinking action is not accurate.