Before sectioning, the blocks made with either paraffin or water soluble wax should first be chilled.

• A. Chilling
• B. Heating
• C. Staining
• D. Equilibrating

Answer: (A)

Chilling improves sectioning quality by hardening the embedding medium and the block itself. When paraffin or water-soluble wax is cooled, it becomes rigid, which allows the microtome knife to slice through with less deflection. This rigidity helps produce smooth, uniform ribbons and reduces knife chatter, tissue compression, and tearing, so the tissue morphology is preserved and thickness remains consistent across sections. Since these embedding media soften at room temperature, cooling them makes the block stable enough for precise cutting. Heating would soften the block and worsen cutting artifacts, staining is done after sectioning, and equilibrating relates to solvent balance during processing rather than pre-sectioning preparation.