What is the name of the bleaching agent used in Gordon and Sweets (G+S) staining?

• A. Oxalic acid
• B. Acetic acid
• C. Sodium hypochlorite
• D. Hydrogen peroxide

Answer: (A)

In Gordon and Sweets staining, the step that clears or lightens unwanted pigmentation after silver impregnation relies on a bleaching agent that can remove interfering pigments without destroying the delicate silver deposits on reticulin fibers. Oxalic acid serves this role well because it selectively bleaches residual pigments and oxidized byproducts that would obscure the fine reticulin network, helping the dark reticular fibers stand out clearly against the background. This makes the subtle pattern of reticulin more easily visible under the microscope.

Other acids like acetic acid aren’t used for bleaching in this protocol, and stronger oxidizers such as hydrogen peroxide or sodium hypochlorite would risk over-bleaching or damaging the tissue and the silver-stained fibers.