Bodian stained sections show light gray nerve fibers. One possible explanation is that the sections were left too long in what solution?

• A. Oxalic Acid
• B. Borax-Ferricyanide
• C. Formalin
• D. Glutaraldehyde

Answer: (A)

In Bodian staining, silver becomes deposited on nerve fibers to make them visible, and a later step uses oxalic acid to halt the reaction and help remove excess or background silver. If sections are left too long in oxalic acid, the silver that has already deposited can be bleached or dissolved, so the fibers lose their dark staining and appear light gray. The development step with borax-ferricyanide is what builds up the silver deposit, so overdoing that would typically darken the fibers rather than lighten them. Fixatives like formalin or glutaraldehyde mainly affect preservation and do not cause this specific bleaching effect.