Which two substances are clearing agents?

• A. Chloroform and Cedarwood Oil
• B. Xylene and Toluene
• C. Ethanol and Isopropanol
• D. Water and Glycerin

Answer: (A)

Clearing agents are solvents used after dehydration to remove alcohol from the tissue and make it transparent so it can be infiltrated with paraffin. They must be miscible with both ethanol (the dehydration solvent) and paraffin. Chloroform works as a clearing agent because it dissolves lipids and blends well with paraffin, helping the tissue become translucent. Cedarwood oil is also used as a clearing agent in some protocols, offering a less toxic alternative to traditional solvents and it is compatible with paraffin infiltration. Together, these two substances fulfill the role of clearing agents in preparing tissue for embedding. By contrast, ethanol and isopropanol are dehydrants, and water and glycerin are not clearing agents (water hydrates or washes, glycerin serves as a mounting medium in some contexts).