Golgi potassium-dichromate silver-nitrate impregnation

Summary Golgi preparations were made by consecutive treatment of formalin-fixed brain and liver with potassium dichromate and silver nitrate. Impregnated tissue dissected from thin slices of the blocks were studied by X-ray powder diffraction methods, in a diffractometer and a Guinier camera. Such tissue proved to contain crystalline silver chromate, Ag₂CrO₄, both while still in the silver nitrate solution and after dehydration in ethanol and clearing in xylene and xylene-Dammar resin. No other compounds containing chromium or silver were detectable. Formalin-fixed tissue merely treated with silver nitrate contained silver chloride, but in impregnated tissue the amount was too scarce to be visible. Hence, silver chloride was no integral part of the Golgi precipitate.A number of mostly ethereal oils traditionally used for clearing histological sections, did not cause the appearance of metallic silver in detectable amount in the Golgi preparations. However, after treatment with clove oil and creosote metallic silver was detected in the tissue.This study was supported by U.S. P.H. S. Grant NS 07998. This aid is gratefully acknowledged.We are indebted to Miss I. Madsen and Mrs. K. Sörensen for technical assistance.