Silver Impregnation Technics for Neuropathologic Studies: I. Variations on Bodian's Technic with a Review of the Theory and Methods

Abstract A plethora of silver impregnation technics exists for the evaluation of neurologic diseases and neuroanatomy. Most were developed to compensate for deficiencies of other methods as applied to the projects of the authors. This paper reviews the chemistry of silver impregnation at the light, ultrastructural and molecular levels. Successful impregnation of axons and neurofibrils results from a series of electrochemical oxidation-reduction reactions. For the first time, we offer an explanation of the stoichiometry of gold chloride toning and of oxalic acid reduction. The histochemical theory of Bodian-type impregnations is discussed and illustrated schematically.