Sulphite pulp is produced from the wood of coniferous trees. Wood chips are cooked in calcium bisulphate or sodium sulphite, and bleached, producing fairly long strong fibers. Since the end of the 1860's until recent years, it has been the most widely used pulp in America. In fact, the term"sulphite" has become generic and is still accurately used to describe any paper made from wood in distinction from papers made from cotton or other fibers. Sulphite pulp is available in a range of grades up to pure alpha cellulose.