I have previously reported ¹⁾ that the rate and the velocity of the bacterial decomposition of the extractive matter of a meat vary with the kind of aquatic animals and that these are nearly constant in the case of the extractive matter of a definite aquatic animal.
The present paper embodies my observations on the rate and the velocity of the bacterial decomposition of the mixtures in various concentrations of two kinds of the extractive matter (red meat fish such as Scomber japonicus and white meat fish such as Palalichthys olivaceus), and on the growth of bacteria in the solutions of the mixtures.

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No reports, it seems, have ever been made of the extraction of alginic acid through the agency of acids. I made an experiment on its extraction employing some acids, in consequence of which alginic acid was proved extractable by 0•1 N. oxalic acid. By the extraction white flocky substance was obtained, which was estimated because of the amount of frufurol and co!our reaction as almost pure sodium alginate, although this showed very low viscosity. Of this preparation, however, purification is very easy so that if this method was further improved, pure alginate with high viscosity would easily be obtained.

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Many researches in ca ?? bohydrates of seaweeds have been reported, in which ketose as well as alc'oses are found. But there have been few reports made in detail of the ketose in ' hydio'sate of seaweeds. To investigate the ketose, the author determined total reducing sugar: fier B_ERTRAND's method and aldose value after K_OLTHOFF's, and calculated the amount of the ketose by the difference between them. If the aldose is present, this difference is to show positive; if not it is to show nought, but never negative.
But on my experiment this difference showed negative value for 18 cases in 19 samples, therefore I investigated about this fact. The result is as follows: 1) Difference between re-ducing sugar and aldose value was the greatest in chlorophyceae, and less in phaeophyceae and least in rhodophyceae. 2) In the case of 15 hrs.' hydrolysis of seaweeds with 3% H₂SO₄. reducing sugar showed maximum value. 3) The substance absorbed by animal charcoal from the bydrolysate was first extracted by the warm 70% alcohol and then that extract was evaporated into syrup to which 95% alcohol was added and a precipitate was thus obtained, which had high aldose value. The extensive reductive power of iodine may be attributed to this precipitate. The hydro'ysate of the precipitate obtained by the addition of base from the acid solublesubstance in seaweed-held very strong reducing power against iodine. 4) It was suggested that the determ'nation of aldose value after K_OLTHOFF did not hold good for hydrolysate of seaweeds.

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Mucilagenous substances of the 6 raw-materials of agar, were separated: 1) Gelidium Amansii L_MX. 2) Gelidium subcostatum O_KAM. 3) Gelidium japonicum (H_ARV.) O_KAM. 4) Acan-thopeltis japonica O_KAM. 5) Ceramium hypnaeoides (J. A_G.) O_KAM. 6) Gracilaria eonfereoides (L.) G_REV. On the mucilagenous substances, the oxalic acid proluced by nitric acid oxidation was quantitatively estimated and the state of hydrolysis in progress by 3% H₂SO₄ was studied.
Similar experiments were carried out on pure saccharides under the equal conditions.
From these results, the following conclusions were deduced; In agar-substances, considerable amount of fructose (or other sugar of like nature) is containd and the sugar is the principal constituent next to galactose.

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By H_IGURASHI and T_AUTI's formulae, the writer ascertained that rate of-decomposition of carp muscle, obeys _VAN'_T H_OFF's law of Q₁₀ (Table 1 and Fig. 1). With 28 kinds of fishes ob-tained from Tôkyô Central Fish Market, he calculated the values of Q₁₀, within the range of 5°-17°C, with the results as shown in Tab. 2. It is remarkable that the low values of Q₁₀ most'y belong to the fishes of cold-water type while the high values to those of warm-water type. The writer gives an explanation, taking the kind of acting bacteria into co isideration.

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By the previously reported method^{(1)( )} the viscosity of 0.5% aqueous extrac's of Gloiopeltis furcata P. et R. and G. tenax (T_URN) J. A_G. was measured at 15°C. The duration and temper-ature of heating before the measurement were found to change the viscosity of the solutions as shown in Tables 1 and 2 and in Fig. 1. Fig. 2. illustrates the results of the same experiment with the marketed material, which had been bleached by certain chemicals.

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The material obtained from the Yamaguti Prefecture in November 1936 to March 1937 was studied with the following results:-(1) A linear relation was found between the fat-content and body weight (Figs. 1-5); (2) the slope of the straight line indicating the above-mentioned relation is slightly steeper in larger specimens than in smaller ones; and (3) no relation exists between the fat-content and coefficient of the thickness of the body of thematerial (Figs. 6-10).

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Twenty-eight specimens of Sardinia melanosticta (T. & S.) were immersed each in 31. of 10%, 20%, 30%, and saturated salt- so:utions kept at 77°F. and 2 or 3 each from these lots were taken out at certain intervals. The contents of water and salt of the flesh were meas u ?? ed as illustrated in Figs. 1-10.

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The crawling speed of the gill pieces of Paphia philippinarum was measured in relation to temperature. It was found to be zero at 0°C and 36°C, and the maximum value, 2•39 cm/min., was obtained at 23•4°C., as shown in Fig. 1. The sea-water was maintained at the same salinity throughout this experiment, its specific gravity being 1•01812 at 15°C.

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Almost no work has been done with running water in the determination of the oxygen consumption of a crustacean. R. G. C_LAUSEN's apparatus (1936) for the determination of the oxygen consumption of fishes was slightly modified and used for Potamobius, which had been imported from U.S.A. and propagated in the interior waters of Japan. As illustrated in the a?companying figures, all the crawfishes used agreed in having a low oxygen consumption between 8 A.M. and 4 P.M., while between 8 P.M. and 4 A.M. there is a time of higher consumption of oxygen. Generally speaking, the experimental animals consumed less oxygen at 5°•8-6°•5C (Fig. 1) than at 8°•5-9°• (Fig. 2).

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1, 758 individuals of the samples for 1936 were analysed by the same method as used in the previous three reports, and were obtained the nearly same results.

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