Fixatives substituting zinc for mercury do not need to be treated 
with iodine and thiosulfate.  "De-Zenkerizing" removes mercurous 
chloride particles, so fixatives without mercury can avoid this 
process.

Dick

-- 
Richard W. Dapson, Ph.D.
Anatech Ltd.
Battle Creek, MI
800-ANATECH (800-262-8324)
email@anatechltdusa.com
Web address:  anatechltdusa.com