This study was undertaken to improve the papermaking properties of pulps consisting of thick-walled fibers by developing the fiber flexibility. On treating bleached kraft beech wood pulp with mixer (kitchen aid) or pebble mill under certain conditions, the loosening of the textures of the inner cell walls developed, especially in the latter, without remarkable damage to the cell wall. This was proved by microscopic examination, partly by use of a two-color staining technique.However, on the rigid pulp with a comparatively high viscosity the plasticizing effect was not found on mixer treatment, so that the best effects of pebble mill pretreatment, determined by the two-color staining were investigated. Thus, a combination of pebble mill treatment and careful beating in a laboratory beater resulted in increased strength properties, especially in folding strength.

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To follow the previous report, the various effects of surface-active additives upon the viscose processing performance of the sulphate dissolving pulp were observed.
Some kinds of non-ionic and anionic surfactants have given definite improvements to the viscose processability of sulphate dissolving pulp, the extents varying according to analytical qualities and chemical reactivities of the pulps used.
The functions of nonionic surface additives are related with the chain-length of their hydrophile radicals, and the most favorable range of chain-length of ethylen oxide for the surface active additive was observed to come between 30 and 50 mols in case of the nonionic surfactants used in this experiments.
In order to ascertain how surfactants function in viscose processes, a nonionic surfactant was applied in various stages of viscose preparation. The best results were obtained when the surfactant was added at the shredding of alkali cellulose. It is presumed that the improving effects of surfactants for filterability of viscose is mainly attributed to their function as a aid for xanthation reaction and dissolving of xanthate.
The floating tendency once incited in the steeping liquor of the pulp sheets when treated by surfactants has been practically lost after the seven months' storage of the pulp sheets.

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In previous paper, relations between the degree of hydrolysis and the morphological structures of fibers were discussed.
In this paper, for the purpose of examining the relations between the morphological structures and several properties of cellulose fibers hydrolyzed by acid, pentosan and the average degree of polymerization of cellulose were determined on the following samples prepared from pine and beech (holocellulose, hydrolyzed holocellulose, holocellulose treated with 5% KOH, holocellulose treated with 5 % KOH and then hydrolyzed). The fractional dissolution curves of nitrates of the samples were also obtained by means of ethyl acetate-ethyl alcohol mixtures.
Some differences both in the behaviors of pentosan and in the resistances of the cell walls during the hydrolysis are recognized between pine tracheid and beech wood fiber.

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