The prehydrolysis treatment of wood chips is generally adopted for the manufacture of dissolving sulfate pulp, because this treatment selectively removes pentosan from wood. Instead of water if xylenesulfonate is used in the prehydrolysis, a considerable amount of lignin will be removed with pentosan, and consequently shortening the time of sulfate cooking after prehydrolysis and the improvement of yield and qualities of pulp may be expected.
Beech wood meal and beech wood chips were treated with an aqueous solution of xylenesulfonate to find a suitable condition of prehydrolysis, varying concentration of reagent, pH, cooking temperature and cooking time (Tables 15). As a comparison the prehydrolysis treatments with water were also carried out. From the results of treatments, the following conditions seem to give a good effect : concentration of xylenesulfonate, 25% in weight ; pH of xylenesulfonate solution, 6.1 ; maximum cooking temperature, 160°C ; cooking time at maximum temperature, 2 hours ; in this case the yield of prehydrolyzed chips was 71.8%, contents of lignin and pentosan in chip were 19.9% and 12.5%, respectively.

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Beech wood chips prehydrolyzed with an aqueous solution of xylene-sulfonate and water were cooked by sulfate pulping process, and the rates of dissolution of main wood constituents and the properties of pulps thus obtained were compared. The results are as follows :
(1) If a 25% xylenesulfonate solution (pH 6.1) are used, 120 minutes prehydrolysis at 160deg;C gives a better effect on the succeeding sulfate cooking than 80 minutes and 160 minutes prehydrolyses.
(2) The xylenesulfonate prehydrolysis gives a better effect on the succeeding sulfate cooking than the water prehydrolysis. In the former the rate of delignification is greater and less cellulose is decomposed during sulfate cooking. However the rates of dissolution of pentosan from chips prehydrolyzed in the two methods are nearly equal during sulfate cooking.
(3) The facts, given above, indicates that the xylenesulfonate prehydrolysis tends to shorten the time of sulfate cooking, and gives pulp of high α-cellulose content at higher yield. The distribution of polymerization degrees of cellulose in pulp, prepared by the xylenesulfonate prehydrolysis, is more homogeneous, too.
(4) Though the experiments of bleaching and purification of unbleached pulp have not been carried out, it may be expected that the xylene-sulfonate prehydrolysis gives more bleachable pulp than the water prehydrolysis at same pulp yield. By the xylenesulfonate prehydrolysis, the preparation of pulp where α-cellulose content is not less than 97% may be also expected without special treatment of purification.

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This investigation was carried out to throw light on the mechanism of difficulty to pulp larch heart wood (I). Ezomatsu (Picea jezoensis Carr.) wood (II), I and larch sap wood were cooked with four different sulphite pulping liquors (Ca-, Mg-, Na- and NH₃-base). The same cooking condition was used for every autoclave cooking : 7% T-S0₂, C-SO₂, 1:6 wood to liquor ratio, 140°C (6+α hrs.). As shown in Tab. 1, larch sap wood was pulped very well as II, but I scarcely pulped by Ca-base while relatively well by NH₃- or Na-base. Mg-base is situated between Ca and monovalent bases for all wood species.
Lignosulphonate (measured by colloid titration with glycol-chitosan (20)), S₂O₃″ and SO₄ ″ in liquor were measured at appropriate intervals during cooking (see Tab. 2 to 4 and Fig. 1). In the case of I, rise of acidity (SO₄ ″ -formation due to decomposition of cooking liquor by taxifolin, ε-galactan and others) comes at relatively late stage of cooking (7.5 hrs.). It is only 1.5 hrs.earlier than that in the case of II. Delignification in cooking of I is, however, very lower from the early stage to the end than that of II. If, at the stage of rising acidity of I (7.5 hrs.), its delignification is comparable to that of II at 7.5 hrs., I might be pulped better, regardless of existence of taxifolin and ε-galactan. It is, therefore, believed that main reason of difficulty to pulp I is due to its slow delignification, which may be caused by hard penetrability of I. Cooking result of I has been improved with soluble bases having good penetrability or by combination of Ca-base and various processes promoting penetration such as Va-purge, vacuum-impregnation and etc. (15). The authors believe that it is unreasonable to explain the difficulty to pulp I only by decomposition of cooking liquor with taxifolin and e-galactan contained in I as believed generally up to date.

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The production of feed yeasts, Myeotorula japonica and strain No. 292 has been investigated. Strain No. 292. was isolated from soil at Akita Tahoku Pulp Co.
On the rate of utilization of reducing sugar, the discontinuous culture method generally dominated over the continuous method.
The principle of the fermentor used in this work was the same as that of Waldhof-type fermentor. But the volume of medium was only two liters which was too little to maintain a steady state of aeration.
It was found that the volume of medium must he four liters at least to investigate the continuous method with this apparatus. Among six kinds of nutrients groups added to neutralized sulfite waste liquor supplementally, no great difference was recognized as for the yields of yeasts and the utilization of sugars.
On the other hand, methods of pretreatment of sulfite waste liquor will preferably exert influences upon them.

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The average fiber length λ in an area T can be estimated by counting the number of the intersections of fibers with a pattern A. (1) (2) (3) The precision of this method is discussed . When the direction and the location of A in T are choosen randomly and T satisfies the condition of “unbiasedness” (3) (4) (5), the unbiased estimate of λ is given by following eq.
λ= c⋅Π⋅D / n
Where c is the average number of the intersections, n is the average number of fiber ends in A, (average is taken for the number of traveling times of A.), and D is a reciprocal of the line density of the pattern.
The major error is due to the arrangement of fibers on A, that is c for a fiber varies according to the relative direction and the position of fiber against A.
When the pattern is consisted of the straight lines uniformly spaced at distance d from each other and fibers also straight, the variance caused both variables is calculated as
σ²= 0.234λ²+0.411d² / ν (parallel grid pattern D=d)
σ²= 0.0191λ²+0.411d² / 2ν (square lattice pattern as fig. 1B, D=d/2)
ν is the total number of fibers inside A.
The model experiment showed that above σ² was nearly proper as the variance of λ if we could minimize the error due to the judgment of the crossing. The effects of the fiber shape and the pattern character are discussed.
A square lattice pattern is efficient for determining λ.

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