Hot chloroform does what?

• A. Removes all lipids
• B. Dissolves proteins
• C. Stains lipids
• D. Dehydrates tissue

Answer: (A)

Hot chloroform is used to defat tissue by dissolving lipids. It’s a nonpolar solvent, and lipids dissolve in nonpolar media, with heating speeding up the extraction by increasing diffusion and solubility. This defatting step helps tissue infiltrate with paraffin and allows uniform staining later. It does not dissolve proteins in a routine histology sense, it does not stain lipids, and dehydration is performed with graded alcohols, not chloroform. So the best description is that hot chloroform removes lipids. (Note: due to toxicity and safety concerns, many labs avoid it in favor of safer alternatives.)