A technique of silver impregnation for nervous tissues with some thiocyanates

Taking advantage of some properties of thiocyanates, a technique of silver impregnation for nerve fibres in the human central nervous system is described. The following procedure is suggested: frozen sections 25-35 micrometer thick, 5-10% aqueous solution of ammonium thiocyanate or potassium thiocyanate, 10% aqueous solution of silver nitrate, ammoniacal silver solution, reduction in 20% formalin, gold toning, dehydrating and mounting. By this procedure, fine fibres appear in the color range from purple to dark purple on the almost colorless background.