A simplified Timm stain procedure compatible with formaldehyde fixation and routine paraffin embedding of rat brain.

A simplified sulphide/silver technique for visualizing transitional metals in rat brain is described. It consists of: (1) sulphide perfusion before formaldehyde perfusion, (2) routine paraffin embedding and sectioning, and (3) silver staining with physical developer. This method is compatible with formaldehyde fixation, eliminates the need for post-fixation in Carnoy's solution before embedding and does not require low paraffin temperatures during embedding. Once embedded, brains can be stored for months before sectioning without loss of stain quality.