In this paper the distinguishing cytological characters, including chromosome number, karyotype and sex chromosomes, especially their size, shape and type of conjugation in meiosis, have been reviewed, based on the author's own data in 49 species of Asiatic mammals representing eight eutherian orders. The results are summarized in Table 1. The cytological data now at hand seem not to permit any conclusion as to the evolution of karyotype in mammals. The numerical as well as morphological diversities of chromosomes in mamals are very wide, and at present our knowledge of the mammalian chromosomes is still too scanty to warrant any generalizing remarks, regarding the basal or fundamental chromosome number, or the evolutional change of karyotype. The species here under study uniformly show the sex chromosome mechanism of the XY type in the male. Striking variations occur in size and shape of both the X and Y chromosomes from species to species. Special cyto-taxonomic interest attaches to the type of conjugation occurring between the X and Y and the mode of their segregation in meiosis; they also vary by species, but appear on the basis of present study to provide interesting cyto-taxonomic characters.
1. The nature of the differential staining of nucleic acids with methyl green-pyronin was investigated by way of comparing tissue staining with methyl green and pyronin, individually and in mixture, with experiments in which aqueous solutions of these dyes, both alone and mixed together, were added with different types of nucleic acids and nucleoproteins and the precipitates formed were observed microscopically. 2. Evidences have been presented which suggest that differential staining with methyl green-pyronin is not due to true selectivity of non-disaggregated DNA to methyl green on the one hand and of disaggregated DNA and PNA to pyronin on the other hand, but rather to preferential tendencies of these nucleic acids in combining with respective dyes in fixed tissues as well as in aqueous solutions. 3. Some of the discrepancies among the data published by different investigators on the nature of methyl green-pyronin staining are discussed. Acknowledgements. I would express my hearty thanks to Dr. O. Itikawa, Director of the Medico-Biological Institute, Minophagen Pharmaceutical Co., for his interest in this work and encourragement throughout the course of investigation. Thanks are also due to late Miss H. Kawamata, Miss S. Takeda, Minophagen Pharmaceutical Co., and to Dr. H. Matsuda, Mr. M. Fukuda and Mr. O. Harikane, University of Osaka for their assistance. Further it is my pleasant duty to mention my indebtedness to Prof. S. Hosoya and Dr. T. Homma, Institute for Infec-tious Diseases, University of Tokyo, for facilities in utilizing laboratory equipments in the course of extracting pDNA used in this investigation.
1. Thionin, being a basic dye of thiazine group, stains DNA and PNA of the cell differentially in blue (α) and purple (β) respectively. 2. Metachromasia of thionin ' can be observed in vitro by mixing solution of the dye with various amounts of nucleic acids of whatever type. When large excess of nucleic. acids is added with small amount of thionin, the color of the solution is blue (α); increase in the amount of the dye in comparison with that of nucleic acids causes gradual change of the color taken by the solution from blue to purple (β) and finally precipitate in the latter coloration appears. 3. Marked metachromasia caused by nucleic acids in vitro is shared by toluidine blue and cresyl violet, but metachromatic staining of nucleic acids in situ with these dyes can not so readily observed as with thionin., 4. Either of the α- and βcolors taken by these dyes can readily be distinguished from the metachromasia caused by mucopolysaccharides (γ-color). 5. Staining of nucleic acids with toluidine blue is partially inhibited by the presence of sodium chloride in high concentration. Thionin-nucleic acid complex can be dissociated by saturated sodium chloride solution in vitro as well as in situ. These facts suggest that nucleic acid stainings with thionin and toluidine blue are of electrostatic nature. 6. Partial inhibition of the staining reaction of nucleic acids with thionin, toluidine blue, or cresyl violet by different means gives rise to PNA stained in a-color, which otherwise stains in β-color. 7. On the basis of an experiment using histone and DNA, the a-color of thionin taken by cellular DNA is assumed to be resulted from competition of proteins for binding DNA. No such evidence was ob-tained with cellular PNA. 8. Implications of the metachromasia of some basic dyes caused by nucleic acids and of the ints ference of proteins in nucleic acid staining with basic dyes are discussed. Acknowledgements. It is a pleasure to acknowledge my indebtedness to Dr. O. Itikawa for his encouragement and to late Miss. H. Kawata, Miss S. Takeda, Mr. T. E. Yukimura and Mr. O. Harikane for their assistance.
In most cases, the testes of the Yoshida sarcoma rats were confined to the abdominal cavity during the latter part of their life span. These elevated testes are highly disorganized showing a remarkable decrease in size. Quite similar condition of the testis was found to occur also in the MTK-sarcomas. Microscopical observations of the elevated testes showed that little or no spermatogenetic activity was occurring. The seminiferous tubules had shrunk as a result of the disintegration of germ cells. The germ cells showed various types of mitotic abnormalities. A tentative conclusion was made on the cause of the degeneration of germ cells in the elevated testis of the tumor animal that, the influence of strange environmental condition of the elevated testis, coupled with the effect of the injurious body fluid produced by the tumor, may form the cause of the disturbance in the supplies of blood, nutrient and other secreting substances in the testis, and this may result in the production of mitotic abnormality in germ cells which are most suscep-tible to strange environment.
The spermatozid of Marchantia and Dumortiera is composed of the nucleus, the “V” portion and the “P” portion. The “V” portion is composed of the large grobule of carbohydrate (C) and its cytoplasmic sheath. In the “P” portion a small plastid (D), can be observed, attached to the “C” grobule. The spermatozoid in or around the, neck-portion of the archegonium of Marchantia has a plastid in its posterior cytoplasmic portion as it was and is thought to bring the plastid into the egg-cell in fertilization. The behaviour of the plastid in fertilization will be discussed in Anthoceros, Dumortiera and Athyrium in the future publication.