The author gained the results as follows: (1) The main factors by which the cellulose in the Karamatsu heart wood sulfite pulp is degenerated (hydrated) are the acidic sulphur compounds among which sulphuric acid is in a large quantity but organic acids are in a little quantity. (2) The degree of the black digestion with Karamatsu heart wood is decreased by a long time seasoning as the sawdust and the content of the produced (organic) acids is also decrased in a large quantity. (3) When the pulp is made from the sawdust of the wood by sulfite method, the α-cellulose percentage in the total cellulose in the sulfite pulp can be calculated by an experimental function and the ratio of the free SO_2 and the produced acid in the waste liquor. (4) The degree of the degeneration of the cellulose in Karamatsu heart wood sulfite pulp is more and more decreased by the seasoning as the sawdust in a long time.