The Golgi-Hortega-Lavilla technique, with a useful additional step for application to brain tissue after prolonged fixation.

The Golgi-Hortega-Lavilla silver impregnation technique was successfully applied to brain slices of various species that had been fixed for six to 24 months in a glutaraldehyde-paraformaldehyde fixative. The procedure is described in detail. Aside from being able to use material after prolonged fixation, the technique has the following advantages: 1) the impregnation is stable and yields constant results at all levels of the central nervous system, and 2) contrast is enhanced because any background precipitate that forms during staining is cleared with potassium cyanide. The possibility of using this method on material held in fixative for even longer periods is suggested.