Use of the Silver-Hydroquinone Sequence for the Display of Reticular Fibers

Abstract

Although many techniques for reticulum depend on the reduction of ammino silver by formalin, silver proteinate reduced by hydroquinone is equally feasible. Procedure: Fix 1-3 days in formalin or in Bouin's, Bodian's, or Carnoy's fixative; take paraffin sections to water; place in 30% aqueous phosphotungstic acid, 3 min; wash 1-2 min; rinse in 90% ethanol; place in 95% ethanol containing 1% tannic and 2% glacial acetic acid, 2 min; rinse 3 times in distilled water; impregnate in 10% aqueous AgNO₃, 1.5-2 hr at 56 C; pass through 3 changes of distilled water, 30 sec each; give a second silvering in 0.2-0.4% protein silver (proteinate d'argent—Roques, or Protargol-S—Winthrop, were used), 2-5 hr at 37 C; rinse in distilled water; reduce in a solution containing 1% hydroquinone and 10% Na₂SO₃, 3-5 min; wash well, rinse in distilled water; tone in 0.5% gold chloride, 10 min; wash 2-3 min; reduce in 2% oxalic acid, 4-5 min; wash well; place in 5% Na₂S₂O₃, 5-10 min; wash; counterstain if desired (hematoxylin-eosin can be used); dehydrate, clear, and cover in balsam or a synthetic resin. Reticulum is stained jet black; collagen, rose. Alternatively, reticulum can be displayed by the Bodian or by the Holmes method for nerve fibers, provided that sensitization by phosphotungstic acid and alcoholic tannic acid precedes the silver staining.