Jenny Molde in South Africa asks about mercury orange.
I am suprised that Dr Kiernan did not quickly answer with one of his "long answers"! He must be on vacation. His book, co-authored with Dr Horobin (Conn's Biological Stains" 10th edition Horobin, R.W. and Kiernan J.A. Editors 2002 Bios) sayeth:
"Mercury orange: synonyms Bennett's sulfhydral reagent, p-chloromercuriphenyl-azo-alpha napthol. Red sulfhydril reagent....Mercury orange was introduced by Bennett in 1951 for the demonstration of cysteine, glutatione and free thiol groupings in tissue..... Other uses are in flow cytometry" The book says more, too much to write here.
I recommend this book for any histology lab doing different research projects in histology. It brings up to date information in previous editions edited by Dr Lillie.
You should buy it!

Mike Titford
USA Pathology
Mobile AL USA