Suppression of Costaining of Nonnervous Tissue in Protargol Technics

If, in the procedure of staining nerve fibers in mounted paraffin sections with Protargol according to Bodian, the reduction after toning with gold chloride is executed in a solution of 3–6 drops of aniline oil in 100 ml of 50% alcohol instead of in the prescribed oxalic acid solution, the selectivity of the staining of peripheral nerves is increased. This is effected by a reduction in the intensity of the staining of nonnervous tissue elements. However, at the same time the staining of nonnervous tissue is richer in details and consequently more satisfactory from a histological point of view than it is according to the original method of Bodian or the modification of this method by Ziesmer (1951).