Paraffin that is considered soft is most useful when thick tissue sections are desired.

• A. Soft paraffin
• B. Hard paraffin
• C. Medium paraffin
• D. Very hard paraffin

Answer: (A)

Cutting thick tissue sections requires a paraffin that offers less resistance to the knife. Soft paraffin is more pliable and shears cleanly, allowing thicker ribbons to be produced without tearing or chatter. If the paraffin is too hard, the knife has to work harder to cut, increasing compression, snagging, and breakage—problems that are amplified with thicker sections. Medium and very hard paraffin are better suited for standard or very thin sections, respectively, but are not ideal when the goal is thick sections. Thus, soft paraffin best accommodates the need for thicker tissue sections.