(1) Introduction.
(2) Problems on the Chemical Constitution of Lignin. By means of hydrogeniolysis.Y. Hachihama and S. Jyodai concluded in 1943-1944 that there were to be three kinds of lignin building stone (I), (II) and (III). (I) is only concerned to the consti-
(I)
(II)
(III) tution of soft wood lignin. Hard wood lignin shall be constructed from building stone of type (I) and (II). Grass lignin shall be constructed from all these types. In 1944, S.Jyodai obtained a dimer of the building stone from Ezomatsu by means of hydrogenolysis which was named Hydrolignin. The constitution of this Hydrolignin, in which two moles of lignin building stone combined in their side chains each other, was discussed. (3) Problems of Pulping. Sulfite pulping of heart wood of pines was discussed. The diffi culty of these sulfite pulping was conquered by adding a small quantity of cationoid reagent such as formalin. (4) Problems of Derivatives of Lignin. (5) Problems of Utilization of Lignin. (6) Conclusion.

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Authoheld the doubt that, according to the construction of synthetic lignin analog (A. Russel;J. Amer. Chem. Soc. 70, No. 3, 1060 (1948)), when it is oxydized, isohemipinic acid is produced but not veratric acid (lignin oxydations product), therefore supposed that the synthetic lignin analog would be different from the lignin in the wood.
In order to study its true form we observed the ultraviolet absorption spectrum of gymnosperm lignin and its analog by Hartley-Baly method.
In the dioxan-, ethanol gymnosperm lignin they had respectively one absorption band, the maximum absorption was 280mμ and the minimum absorption 261 mμ.
On the other hand the synthetic analog had two absorption bands, in the 1st absorption band, the wavelength of the maximum absorption was 280mμ, the minimum absorption 275mμ, in the 2nd absorption band, the wavelength of the maximum absorption was 265mμ, the minimum absorption 260mμ.
So we have supposed that the synthetic analog was different from the gymnosperm lignin in the wood.

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Employing birch woods (in Hokkaido) the influences of amounts of chemicals added (Na₂SO₃) and the cooking temperature upon the qualities and the strength properties of the products were studied. In some additional digestions, a small amount of Na₂CO₃ or NaHCO₃ besides Na₂SO₃ was added to cooking liquors.
As the conclusions from the results obtained,
1. it is possible to obtain the semi-chemical pulp which has simultaneously the whiteness of unbleached sulfite pulp and the strength of kraft pulp.
2. there is no necessity to employ above 20% of chemicals and no advantage due to addition of Na₂CO₃ or NaHCO₃, from the standpoint of either qualities or strength properties of the cooked.

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Our experiments were to find out the means of making a highly uniform pulp in chain-length distribution . At first, measurements were repeated on different kinds of pulps with regard to chain-length distribution.The results obtained were as follows :
(i) There are four parts in the differential distribution curve of the usual rayon pulp. (PD. about 900). These parts exist severally at about 1000-1300, 400-600, 200-300 and 0-100 of PD. and they all show relatively sharp peaks.
(ii) Pulp of low viscosity, (high alpha-cell. and PD. about 750) has to parts, severally at about 200-300 and 500-1000. The former curve rises in sharp peak, but the latter in flat one.
(iii) Pulp of high viscosity has three parts, at about 200-300, 1000 and 1300-1800 each, of which the last occupies the main part and shows a flat curve, while the other two are in sharp curves.
(iv) When the short fibers are removed from the usual rayon pulp, the distribution curve obtained is in a very sharp peak at about 1000.
Our conclusions from the above results are as follows :
(i) There are some periodic weak points in solid-cellulose for chemical operation, such as sulphite pulping procedure and it is understood that PD. 1000, 500 and 300 are easily made by chemical depolymerization.
(ii) We can not obtain a highly uniform pulp of chain-length distribution by chemical procedure alone ; mechanical screening at the last stage before drying has also to be used.
Our researches will be continued in order to throw more lights on the problems herein discussed.

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Yield of washed unbleached pulp is at a 75%, of that of pine. Pitch trouble occurs very rare ; on the contrary, separates again the pitch deposited on pine S. P. Unbleachability of the ceder pulp is due to its heart wood. The splint wood pulp is easy bleachable, having possibility available as RP in the future. Being easy beated, freeness of unbeaten pulp corresponds to that of pine pulp beaten for 3 hours. Breaking length is increased by 11.3% in l . d. and by 35 in c. d., and bursting ratio, increased by 42% . Color of pulp is inferior.

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The-wtiter has given empirically the following formula on the efficiency of drum barker,
Efficiency=0.713πdlN/10000 Koku/hour
where, d=dia. of drum (ft)
l=length of drum (ft)
N=no.of revolution of drum per hour.

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