(1) Although the silk-layer weight of females is usually heavier than that of males in the common silkworm strain, this relation is reversed in the W-translocated strain.
(2) The functional relationships among the three organs, brain, suboesophageal ganglion and corpora allata which are related to quantitative characters such as the weight of the silk-layer and voltinism were examined in a series of experiments in organ transplantation.
(3) By transplantation of the brain-suboesophageal ganglion complex of females of the W-translocated silkworm strain to “non-diapause larvae” the silk-layer weight of the recipient is more decreased and voltinism is more strongly changed in non- diapause direction than in the case of transplantation of suboesophageal ganglion alone.
(4) By transplantation of the brain-suboespohageal ganglion complex of males of the W-translocated silkworm strain to “non-diapause larvae” the silk-layer weight of the recipients is more increased and the voltinism is more strongly changed in diapause direction than in the case of transplantation of the suboesophageal ganglion alone.
(5) By transplantation of the brain-corpora allata complex of females of the W-translocated silkwrom strain to “diapause larvae” the silk-layer weight of the recipients is more decreased and the frequency of non-diapause eggs within one batch becomes higher than by transplantation of corpora allata alone.
(6) By transplantation of the brain-corpora allata complex of males of the W- translocated silkworm strain to “diapause larvae” the silk-layer weight of the recipient is more increased and the percentage of non-diapause eggs in one batch (laid by one moth) is more decreased than in the case of transplantation of corpora allata alone.
(7) It is assumed from the above-mentioned findings that the brain of females of the W-translocated strains weakly inhibits the functional activity of suboesophageal ganglion and weakly acclerates that of corpora allata through nerve commissures. It seems, on the contrary, that the brain of males of the same strain weakly accelerates the functional activity of suboesophageal ganglion and weakly inhibits that of corpora allata through the nerve commissures.

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The present investigation deals with the cytotoxic effect of cytotoxin produced in the mouse ascites which was previously inoculated with the Yoshida sarcoma subline C cells, upon living tumor cells.
The supernatant of the mouse ascites (ARF solution) obtained on the 7th day after inoculation of tumor cells of tho Yoshida sarcoma subline C contains a certain cytooxin. That cytotoxin acts strongly upon the tumor cells in vitro as characterized by cellular damage after they displayed an amoeboid movement.
The cytotoxic activity of the cytotoxin increases remarkably after the addition of normal rat serum as a complement. The activity of the cytotoxin is neutralized by heating to 56°C for 30 minutes, but it again recovers with the addition of the complement.
The normal serum used as a complement has a little effect on the tumor cells, but enhances the cytotoxic activity of the ARF solution.

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The present study was undertaken with a purpose to find out any fixing and staining method which demonstrates fibrous nature of the mitotic spindle using cultured rat and mice fibroblasts as material, and if possible, to obtain some information on the morphological structure of the spindle. After several trials with current methods available for demonsartion of the spindle structure, it was found that La Cour's method in combination with Lewitsky's fixative and aniline blue-orange G stains has been proved to be the most satisfactory one for the subject in question in the course of spindle formation in prophase through metaphase. Examination of the material treated with the La Cour's method has revealed that the formation of the spindle initiated by the appearance of fibrillar bundles running through the center of the nucleus and then they converged to at the centrosomes locating one each at the opposite sides of the nucleus. The fibrillar bundles showed a gradual development leading to the formation of the spindle. Surrounding the spindle thus formed there occurs a membranous structure which delimits the spindle from the cytoplasm. Remarkable fact is the presence of a clear zone between the membranous structure and the spindle surface. The clear zone is obviously discernible by its weak stainability from other parts of the cytoplasm. No chromosomes were found lying outside the clear zone. By several other methods the existence of the clear zone was also proved, though not very clear. The phase microscopy observations of living fibroblasts in vitro were also succeseful in demonstrating the occurrence of the clear zone by its low refractive index. The clear zone contains no visible granule. The membranous structure seems to serve to prevent cytoplasmic inclusions from entering into the clear zone. The structure is rather clearly visible at prophase and metaphase, while indistinct at ana and telophase. It remains unknown whether the membranous structure is of nuclear origin, or not.
The treatment of living fibroblasts with dilute acetic acid resulted in a gradual coagulation of the protoplasm, while the spindle fibres and clear zone become visible for a moment. This fact seems to support the evidence obtained in fixed and living materials for the existence of clear zone.
The in vitro observations of dividing spermatocytes of the grasshopper, Chrysochraon japonicus, seem to show that the metaphase spindle consists of two components, one being of cytoplasmic origin and the other of nuclear origin. The clear zone is not evident in the spindle of grasshopper spermatocytes, but the nuclear membrane was found to exist throughout the whole process of spindle formation in prophase and prometaphase.

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組織培養した紡錘形細胞肉腫におよぼすマイトマイシンの影響を細胞学的, 細胞化学的に研究した。マイトマイシンは特に静止期にある細胞に第一義的に作用し核のDNAおよび仁のRNAの構成に変化を起こし, 細胞の機能を乱し崩壊に導くようである。核は形態的に著しい変化を受けると同時に, その染色質は染色性を失う。特に核染色質の異常な変形と変質を引き起こす。仁もまたその形態, 染色性に著しい変化を起こし, ついには仁物質は細胞質内に流出する。細胞質には多数の空胞が現われる。分裂期の細胞においては染色体に著しい切断や染色体橋の形成がみられ, 分裂ははなはだしく乱される。仁に著しい変性を起こす点においてマイトマイシンの効果は特異である。

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