What corrective step should be taken to fix the problem of mounting medium on top of the coverslip?

• A. Remove the coverslip and reapply a new one
• B. Re-stain the slide
• C. Wash with water and re-mount
• D. Ignore and proceed to analysis

Answer: (A)

Mounting medium belongs between the slide and the coverslip, not on top of the coverslip. When the medium sits on the outer surface, the mount isn’t properly sealed and may cause uneven mounting, air bubbles, or optical distortion.

The correct fix is to remove the coverslip, wipe away any excess mounting medium, and re-mount with a fresh drop of mounting medium placed on the slide before gently lowering a new coverslip. This ensures the medium is sandwiched correctly and yields a clear, stable visualization for analysis.