Which clearing agent is suitable for nervous tissues and embryos?

• A. Benzene
• B. Chloroform
• C. Xylene
• D. Toluene

Answer: (B)

The key idea is matching a clearing agent to the tissue’s delicacy and lipid content so that the tissue becomes transparent and can be infiltrated by paraffin without substantial distortion. Nervous tissue and embryos are especially lipid-rich and fragile, so a clearing agent that dissolves lipids well and penetrates this type of tissue effectively helps preserve morphology during infiltration. Chloroform fits this niche because it clears and solubilizes fats efficiently, allowing good paraffin infiltration with relatively gentle shrinkage and distortion compared with harsher clearing agents. That makes it especially suitable for delicate nervous tissues and embryos. In contrast, benzene is highly toxic and largely avoided; xylene is a common but more aggressive clearing agent that can cause more shrinkage or distortion in delicate tissues; toluene is also less optimal for rapid, gentle clearing of such specimens. Always remember the safety concerns with chloroform, as it is toxic and used with proper ventilation and precautions.