There are many published methods for the digestion of fish tissue. Most involve the use of three reagents, with one method requiring the use of no less than six reagents. Velgheet al. describe a method whereby a small piece of fish tissue is mixed with potassium permanganate and sulphuric
acid, and then digested on a hot-plate. After digestion, the excess permanganate is reduced with hydroxylamine hydrochloride.