Pulp was dried up by High Frequency Radio Waves (35 M. C.) when it was cut off trom the humidity of atmosphere. Moisture content of pulp was determined by this method easily and quickly. No breakdown of cellulose molecules was admitted with this treatment if suitable conditions were selected. Suitable conditions of various samples were studied. (Tube input power 50 watt, 10 minutes for sheet type pulp ; 70 watt, 30 minutes for fleecy type, etc.)
Data by this method were compared with that by the standard drying method. There were no differences between them.

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As to the utilization of the sulfite waste liquor in Japan, it is not so flourishing that the greater part of it is now still being dumped into streams except being used by only two plants in the manufacture of industrial alcohol.
Since the end of II World war, some investigations to produce food yeast from the liquor have been carried out by Kokusaku Pulp Industrial Co. Ltd. but the industrialization of the manufacture has not yet been achieved because of the slight demand of the product in the Japanese stock-farming industry.
Some reports in the United States (Ind. Eng. Chem. Aug. 1951., Paper Trade Jour. Sept. 1951., Tappl, Oct., 1951 etc.) show that a plant of the dried food yeast, daily amounts of 4.5 tons, was already established in 1947 and is meeting some demands in the United States.
The present report is summarized as follows :
(1) Laboratory experiments : Comparative studies on the growth rate, time, and properties of the product between Mycotorula japonica and other seven strains of pentose-utilizing yeasts.
(2) Pilot.plant tests : Aeration rate and the yields ; yeast density and the fermentation time ; pH, feeding velocity and sources of nitrogen of the feeding liquor were investigated.
As the results of these experiments, the above eight strains were revealed to have about the same activity of utilizing pentose. Strain (28) has rather small cell but the product is pretty white and has rather high growth rate as well as the strain (78). Further experiments should be carried out for the selection of the more powerful pentose utilizer.
Pilot plant test by means of the Waldhof fermentor ; it was unnecessary to use antifoaming agent as in the case of the usual 1 vat system and the fermentation time was markedly shortened. An interesting point of the process is that considerable amounts of the product can be obtained notwithstandingthe small capacity of the propagator. The careful control technique of theliqu or feeding is necessary for the continuous fermentation. The more profitable apparatus of co ntinuous operating process in yeast separation, washing and drying must be designed.

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The one-step replica collodion method was adopted for making replicas, suitable for examination in the electron microscope, of the surface of the wood pulp fiber without subjecting the fiber to heat and pressure. The electron micrographs of wood fiber surfaces obtained by this technique coincide with the views of cell wall structure that have been hitherto suggested from the polarisation microscopic studies and others and reveal new finding concerning submicroscopic structure.
The electorn microscopic interpretation of delignification process is discussed briefly using the very raw cooking pulps.

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Unbleached sulfite pulp, preliminary treated with chlorine water, extracted with Na₂SO₃ solution and washed with water, was subjected to cold alkaline purification at the consistency of 10%, with 3-12% solutions of NaOH, at the temperature of 25°C., for 1 hr. respectively.
A definite portion of every waste liquor was sampled, completed to an aliquot volume with water, and then (I) directly analysed by conductometric titration with N-HCl solution for the content of total alkali, (II) treated with ion-exchange resin (Amberite IR-120) to remove a greater part of free alkali, whose existence resulted poor end point in conductometric titration for the small amount of combined alkali, and then titrated potentiometrically and conductometrically with N-HCl solution for the accurate determination of combined alkali.
The amount of combined alkali is 1, 0-2, 5% (as equivalent NaOH) based on the weight of original pulp while that of total alkali is 28, 6-111, 0% on the same base.
Free alkali and absorbed alkali (apparent) were also estimated as follows,
Free alkali=Total alkali-Combined alkali
Absorbed alkali (apparent) =Originally used alkali-Total alkali.
Titration curves of II showed the presence of two kinds of acidic organic substance, i. e., A₁and A₂,
where NaA₁+NaA₂= NaA (total combined alkali).
The amounts of A₁ and A₂ in every waste liquor were estimated and their dissociation constants, KA₁ and KA₂, were calculated from pH values of corresponding equivalence points.
KA₁ and KA₂ are always in the order of 10^-4 and 10^-10 respectively.
From their dissociation constant data A-₁ and A-₂ were assumed to be RCOO^-+HCO-₃ and 1/2 CO-₃ respectively and then carboxyl content (sum of the low and high melecular parts) of every waste liquor was computed.
The amount of carboxyl group is 0, 24-0, 37% (as equivalent NaOH) based on the weight of original pulp and that of high molecular part is 1/3-1/5 of the total one.
The ratios of A/Na and A/Nao were also estimated, where A, Na, and Nao were the weight of organic substance dissolved in waste liquor, that of alkali combined with it, and that of alkali combined with carboxyl group respectively.
A/Na and A/Nao are 6-20 and 23-74, they are much higher than that (constant value of 4, 5) obtained in the case of hot alkaline purification previously reported.

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