Oxygen consumption (QO₂) and respiratory quotient (RQ) in endogenous respiration were estimated of the intact midgut tissue in Bombyx larvae. Materials were prepared according to the following procedure; that is, the larvae were at first dissected and after removing tracheae, fat bodies and Malpighian tubes attached to midgut wall, midgut was cut longitudinally and midgut inclusions with the peritrophic membrane were drawn carefully out of midgut. Of the midgut preparations thus obtained, the middle portion colored yellowish deeply was used as a material for the estimation, which was carried out by means of Warburg's manometric method, suspending the materials in the fluid consists of 1.2 ml of 0.7 % NaCl solution and 0.2 ml of phosphate buffer (pH 6.8). Results will be summarized as follows.
1. As will be seen in Fig. 1, Qo2 which is low at the start of the fifth instar becomes higher gradually, reaching maximum at the middle, and then becomes low towards the maturation, ranging in the value from 7.0 to 12.0. The low value of QO₂ in the race of Syuka×Ginrei in Table 1. will be attributed to the effect of a rearing season in which the mulberry leaves are inferior in their nutritive value. Moreover, as is also seen in Fig. 1, RQ maintains the level of approximately 1.0 throughout the fifth instar larval development and this value is lower comparing with the one obtained with midgut homogenate by ITO and HORIE (1959). The reason why RQ with the intact tissue is lower than that with the homogenate and the oxidative significance represented by 1.0 of RQ are both unknown.
2. The starvation has no or slight effect both on QO₂ and RQ, as is shown in Table 2, remaining unknown of its physiological explanations.

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Changes in uric acid content and xanthine dehydrogenase activity of the silkworm egg were investigated during embryonic development.
1. The uric acid content of the egg decreases gradually until the blastokinesis stage, then increases and reaches the maximum level at just body pigmentation stage.
2. Xanthine dehydrogenase activity increases gradually until about middle stage, after that increases markedly, but declines a little at body pigmentation stage.
3. These changes of uric acid content and xanthine dehydrogenase activity during embryonic development in the silkworm egg were discussed with respect to the physiological function of uric acid in the silkworm egg.

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Sericin was fractionated by the methods of KANEKO, MOSHER and KONDO, and infrared absorption spectra of these fractions were measured in the rock salt region by using an NaCl prism. Following results were obtained by qualitative investigation of changes in their absorption bands.
1. Some differences in the infrared absorption spectra were observed between two kinds of sericins fractionated in any of these methods.
2. The infrared absorption spectra of A of KANEKO's method, B of MOSHER's method, and eusericin of KONDO's method were almost alike and showed no remarkable distinction of their molecular structures.
3. B of KANEKO's method, A of MOSHER's method and pseudosericin of KONDO's method gave somewhat different spectra, respectively.
In particular, the infrared spectrum of pseudosericin was clearly discriminated from those of the former two and showed a difference in molecular structure.

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In previous papers the authors poinved out that one: of the important prebursors of glycine synthesis in the silkworm larva was glyoxylic acid. The current study was carried outwith glycolic acid-1-C¹⁴ to find a precursor of glyoxylic acid. synthesis in the, silkworm larva. Amino acids, such as glycine, alanine, serine and tyrosine, were isolated by procedures described bySTEIN and MOORE from the fibroin produced by the silkworms (N124×C124) that consumed 0.5μc/ larva of C14 glycolic acid at the fourth day of the fifth stage. Glyoxylic acid was also isolated according to the procedure described in the previous papers as its 2, 4-dinitrophenylhydrazone from the body fluid of the silkworms (N124×C124) that consumed the glycolic acid-1-C¹⁴ at the third day of the fifth instar. Radioactivities of the amino acids (Table 1) and the hydrazone (Table 3) isolated were measured with an SC-16 windowless gas-flow counter (Tracerlab Inc). The glycine isolated wasdegraded stepwise according to the procedure described by VERNON et al. in order to know the distribution of the C¹⁴ in the glycine molecule (Table 2). The glycine isolated from the fibroin produced by the silkworms that consumed the glycolic acid-1-C¹⁴ had a comparatively higher concentration of the C¹⁴ (Table 1) and all the radioactivity was located in the carbon of the carboxyl group of glycine (Table 2).
Furthermore, a comparatively higher concentration of the C¹⁴ appeared in the glyoxylic acid isolated from the body fluid of the silkworms that consumed glycolic acid-l-C¹⁴ (Table 3). These facts seem to suggest that glycolic acid is used for formation of glycine via glyoxylic acid, and that this reaction plays an important role in the glycine synthesis in silkworm larva.

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[in Japanese]

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1) The formation of fibroblasts can well be obtained when employing a medium which iscomposed of WYATT's inorganic salts, sugars and amino acids (or lactalbumin hydrolysate) inaddition to silkworm hemolymph, however, the effectiveness of silkworm hemolymph was recognizedto be replaced by the addition of dialysate of hemolymph.
2) Substances promoting the formation of fibroblasts were contained in the dialysate ofhemolymph, and not markedly destroyed by treatment with alkali or acid, and seemed to bepresent in a fraction not adsorbed by active charcoal.
3) Formation of fibroblasts was also observed employing a medium which was composed of WYATT'S inorganic salts and sugars, lactalbumin hydrolysate and Difco yeast extract in place of hemolymph.
4) Pupal oviduct showed the best formation of fibroblasts among ovaries and oviducts taken during various stages from the 4th instar to pupal stage.
5) Fibroblast-like cells were observed in the culture of oviduct of Galleria mellonella.

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Bacillus thuringiensis was able to be isolated from the dust of silkworm rearing houses of farmers, suggesting a wide distribution of this sort of bacillus in Japan, though the products from Bacillus thuringiensis have still not been practically used as microbial insecticide up to the present time.
Method of isolation of Bacillus thuringiensis from the dust was also described in this paper.

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C 106-oily or -translucent strain is the recessive and one gene mutant strain derived from C 106 by natural mutation, but in many characters C 106-oily is different from C 106. In F₁- hybrids of C 106-oily and C 106 no heterosis was observed in several quantitative and physiological characters, and the expression of characters of F₁ hybrids was all the same with C 106. From these results, it was considered that the difference in many characters between C 106 and C 106-oily was based on the pleiotropic effects of C 106-oily gene (ο-106) itself.
When C 106-oily gene was homozygous, the mutant gene produced the effect on egg-pigmentationto be paler than that of the normal, and in addition to this effect, other effects distinguishedfrom the normal were observed such as poor growth in body weight, light weights of cocoon and cocoon-layer, small number of eggs laid, poor fertility, low content ofuric acid in larval integument and early critical period in pupation.

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1. The results of investigation on variability in larval body and cocoon weights of single cross and three-way or double cross hybrids were described.
2. Male or female groups of single cross hybrid showed less variability in larval body and cocoon weights than those of three-way or double cross hybrids. On the contrary, regarding variability in cocoon weight of mingled group with male and female, different feature was observed: variability of single cross hybrid was larger than those of three-way or double cross hybrids.
3. Frequency curve of cocoon weight in single cross hybrid was to be bimodal one, while that of three-way or double cross hybrids was to be something like normal curve or notso clearly bimodal one as in the case of single cross hybrid.

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As one of a series of investigations concerning the water economy and dry-matter production of mulberry plant set about by TAZAKI et al. since 1954, this study was undertaken to make clear the first step of the relation between water economy and dry-matter production of this plant, though many questions yet remained unanswered. The experiment consists of two parts.
The tap-root of 40-day-old yearlings with 6 or 7 leaves were cut off at 3 cm under soil surface on July 20, after which leaf water-content was measured with the progress of water deficit in plants. So far as the water-content was kept over lethal water-content (Fig. 1), the leaves recovered from severe wilting in the afternoon during the nighttime, and the lower leaves began to wither in a few days after the treatment, while the upper ones survived this period with scarcely any sign of wilting (Fig. 2). Strong drought resistance of upper leaves is of significance for the maintenance of dry-matter production, for the maximal photosynthetic activity of the 2 nd and 3 rd leaves, over 5mgCO₂/50cm²/ hr (Fig.3), surpassed remarkably those of the uppermost and lower leaves. The susceptibility of lower leaves for water deficit seems, in the present status, to be due to the low values of lethal deficit (normal water-content--lethal water-content) and osmotic pressure of cell sap.
Pot-cultured 2-year-old seedlings with 20 leaves and 60-70cm of shoot length were kept unwatered from a definite day and thereafter the water-content of successive leaves were measured during the critical period. The experiment in August showed similar trend as mentioned above, i. e., the withering was observed at first in lower leaves, but an unexpected result of high water deficit in some younger leaves may require further analysis (Fig. 4). In this case the lower leaves were already “dull”(TAZAKI) with inert stomatal closure at water deficit, which may play some part in the susceptibility of these leaves. In autumnal experiment, the water deficit proceeded uniformly and, consequently, different susceptibility of successive leaves could never be observed, as all leaves had turned to “dull” ones till that time.(Fig. 5).

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An experiment was carried out to ascertain the: freezing temperature in the 2-year-old potted mulberry tree, Ichinose variety, during winter period in Tokyo. The samples were put under various temperatures for about 2 hours in a freezing chamber, and were left in field before and after the treatment above mentioned.
After the middle of October, when the shoot elongation was stopped, the hardiness gradually appeared, and on December 15 the tree was not injured by the low temperature treatment at 19°C. In next spring, the tree was injured by the treatment at 5°C on April 18, the first-stage of bud sprout, whereas on March 27, 20 days before bud sprout, the tree was not injured by the treatment at -15°C.

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