Histochemical demonstration of heavy metals. A revised version of the sulphide silver method suitable for both light and electronmicroscopy

TLDR: It is particularly important to maintain a sufficient but low concentration of sulphide ions during the perfusion to avoid using oxidating or acid fixatives and to ensure low temperatures while embedding in paraffin or during polymerization of Epon.

Abstract: The three steps of the sulphide silver method have been examined: 1) Transformation of metals to metal sulphides; 2) Fixation and embedding or freezing of the tissue for sectioning; and 3) Deposition of metallic silver on the metal sulphides in a physical developer. Based on the results, a revised method is described and discussed. It is particularly important 1) To maintain a sufficient but low concentration of sulphide ions during the perfusion; 2) To avoid using oxidating or acid fixatives; 3) To ensure low temperatures while embedding in paraffin or during polymerization of Epon; and 4) to use a slow-acting physical developer. Examples of the metal sulphide pattern from various tissues are presented.