Chloroform and Cedarwood Oil are clearing agents.

• A. Clearing agents
• B. Fixatives
• C. Dehydrants
• D. Embedding media

Answer: (A)

Clearing agents are used after dehydration to replace the alcohol and prepare the tissue for infiltration with the embedding medium. They dissolve residual alcohol and have a refractive index similar to paraffin, which makes the tissue transparent and compatible with paraffin infiltration. Chloroform and cedarwood oil fit this role because they effectively remove remaining solvent and mix with paraffin, allowing the tissue to be embedded for sectioning. They are not fixatives, which preserve structure by chemical cross-linking; not dehydrants, which remove water during the dehydration step; and not embedding media, which are the substances that surround the tissue during sectioning (such as paraffin). Historically, chloroform has been used as a clearing agent but is toxic, while cedarwood oil is a less toxic alternative, albeit slower.