An argyrophil III method for the demonstration of elastic fibres and membranes.

An esterification with isopropyl alcohol containing 0.2% periodic acid and 2% acetone (at 56 degrees C for 16 hours) followed by a treatment in a special physical developer, similarly, an acetylation with a 3:2 mixture of pyridine and acetic anhydride (at room temperature for 16 hours) followed by the same development, render the elastic fibres and membranes visible. Both pretreatments (esterification and acetylation) serve to make the catalytic points more active in the elastic elements than in the other components of tissue.