Ruthenium tetroxide for fixing and staining cytoplasmic membranes.

Rat liver and kidney were fixed for electron microscopy with ruthenium tetroxide. When compared with tissues fixed with osmiun tetroxide, the membranes showed well without additional staining. The trilaminar structuire of the cytoplasmic membranes was clearly seen. In width the nuclear, mitochondrial, and cytoplasmic membranes investigated resembled the cell memnbrane.