Concentric Layers in the Granules of Human Nervous Lipofuscin Demonstrated by Silver Impregnation

Abstract

Representative pieces of human brain were fixed in 10% formalin, embedded in paraffin and sectioned at 5 μ. Paired sections were used, one of which was oxidized in equal parts of 0.5% potassium permanganate and 0.5% sulfuric acid for 1-2 min, while the other was left unoxidized. Both the oxidized and unoxidized sections were impregnated with silver diamine. The lipofuscin granules in the nerve cells appeared as small intensely stained black dots, surrounded by a clear unstained zone, in the unoxidized sections, while in the oxidized sections there was an outer ring of intensely blackened material surrounding a central unstained dot.