Lynn,
Pyrogallol is used in the silver technique of Palmgren for nerve fibers.
It is an excellent method. I'm not at work just now, so I can't give you
the reference, but if my memory serves me correctly, the method is given
in Bancroft & Stevens. If you have problems getting a hold of it, let me
know and I'll see what I can do.
Best wishes
Ronnie Houston
Cytochemistry & Molecular Pathology
Texas Scottish Rite Hospital for Children
Dallas