An argyrophil III method for the demonstration of fibrous neuroglia.

The catalytic activity of the fibrous astrocytes in the reaction of silver ions with dissolved reducing molecules is considerably increased by ethylation and a subsequent treatment with NaJO3. As a consequence, in a special physical developer they produce metallic silver at a considerably higher rate than do other tissue elements, making possible their selective demonstration. In freshly fixed materials myelin too is silverized. This can be avoided by means of pretreatments with performic acid and iodine.