The PAS-resistance-system of Mycobacterium tuberculosis var. hominis, strain Aoyama-B, has been tsudied from genetic aspect and the following conclusions have been obtained.
Survival curve for the strain plated on medium containing various concentrations of PAS represent two discontinuous points, and population structure of one-step resistant strains obtained by one-step selection with various PAS concentrations also represents a significant change of population structure at the same points. In view of the results, it has been suggested that PAS-sensitivity or PAS-resistance is determined by three genotypes: The first is the wild genotype; The second is the genotype of lower degrees of PAS-resistance (until approximately 10mcg.); and the third is the genotype of higher degrees of PAS-resistance (until approximately 200 to 500mcg.).
Mutaion rates to mutations to these resistant genotypes are approximately 10^-5 and 10^-8, respectively, and the mutations occur independently from each other.
Even in the presence of the same genotype, there is a significant variation of phenotypic expression. Thus, the existence of various degrees of PAS-resistance is interpreted by assuming only a few genotypes and variation of phenotypic expression. It is considered that a discontinuous change of PAS-resistance is derived from the change of genotype and a continuous change of PAS-resistance is done from the variation of phenotypic expression in the presence of the same genotype.
The growth rate of PAS-sensitive cells as well as PAS-resistant mutants varies continuously depending on the PAS concentration. Consequently, the degree of PAS-resistance varies depending on the size of inoculum and the incubation period. Therefore, it is desirable that the degree of PAS-resistance is expressed as the growth rate on a constant PAS concentration or as the highest PAS concentration, on which single cells (a constant size of inoculum giving discrete colonies on PAS-free medium) can give visible colonies after a constant incubation period.
It has been indicated that there is a phenomenon of interferrence of growth between resistant mutants and sensitive cells as well as between reistant mutants of different degrees af resistance.

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Larvae of various stages (5-13mm. in body length and before pupation) in Chironomus dorsalis, were dealt with, and the vesiculation of heavy bands of salivary gland chromosomes, mainly induced by physiological treatment, was studied with the light and phase contrast microscopes (Tiyoda, BM). The treatments were performed prior to aceto-carmine fixation, as follows: (1) glands were exposed for long time (10-12 minutes) to Ringer's solution; (2) treated with N/5 NaCl in weak acid (acetate buffer solution of pH 5); (3) fixed with aceto-carmine in which N/3 Nacl was involved.
The results were discussed on the following three points, in connection with the vesiculation and the chromosomal organization:
1. The vesiculation occurs in each heavy band (band group) in larvae of all stages studied here. This corresponds with the result gotten by Fujii & Kimoto (1955) that the small vesicular bands (bulb formation?) exist in the youngest salivary gland chromosomes (1-3mm. larvae). This would indicate that the heavy band (band group) is already organized in the youngest salivary chromosome.
2. In large chromosomes, a vesiculated heavy band gives two images; one is dispersed chromatin granules with sharp strings in ordinary microscopy, and another one is phase negative, irregular shaped vesicle in phase microscopy. These images must be attributed to different structural elements. The latter image is possibly due to the optical change in chromosomal matrix. This indicates that the latter can not be any evidence for the chromosomal disruption.
3. Finally, considering cytological characteristics of both doublet (Drosophila) and heavy band (Chironomus etc.) i. e., the resistance against stretching, and the ability to vesiculate, it is assumed that they have some common role in chromosomal organization.

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1. In the present reports, the external characteristics, fertility and the number of somatic chromosomes of trigeneric triple F₁ hybrids raised from Triticum persicum×Haynaldia villosa F₁×Secale cereale (Tper HRF₁) and T. durum×H. villosa F₁×S. cereale (Tdur HRF₁) are treated respectively.
2. The percentage of the triple F₁ plants againts the number for the pollinated florets in the hybrid Tper HRF₁ was higher than that of the hybrid TdurHRF₁ (Table 1).
3. The number of somatic chromosomes of Triticum-Haynaldia-Secale trigeneric triple F₁ hybrids was found to vary from 25 to 32 in TperHRF₁ and from 24 to 32 in Tdur HRF₁ (Table 2 and 3). And the somatic number of chromosomes of eu-trigeneric triple F₁ hybrids in these two combinations is 28. This number corresponds exactly to the sum of the gametic numbers of the three parental plants (Triticum persicum or durum 28+Haynaldia villosa 7+Secale cereale 7=28). 7 chromosomes out of the 25-32 or 24-32 chromosomes as the somatic number of these two trigeneric triple F₁ hybrids are from S. cereale as the pollen plant, and the remaining 18-25 or 17-25 chromosomes must have been from TperHF₁ or TdurHF₁ as the mother plants. The number of somatic chromosomes of TperHF₁ and TdurHF₁ in these two combinations was found to be 21 respectively, therefore, up to 21 of the 17-25 chromosomes derived from mother plants are due to the irregular distribution of the chromosomes or to the formation of the equatorial plate, but the 1-4, which is in excess of 21, may be due to the non-disjunction of the chromosomes in the meiosis of the mother plants. And it is difficult to as-certain whether those surplus chromosomes came from the Triticum or the Haynaldia.
4. The variation was observed among these groups and among the individuals of each group, in the external characteristics of these two trigeneric triple F₁ plants. The remarkable differences were observed among the individuals in each group, due perhaps to the different constitution of chromosomes in the individuals of each group, though they have the same number of chromosomes. The external characteristics of these F₁ plants and their parental plants are shown in Table 4 and Photo. 1. Generally speaking, although these F₁ plants possess the external characteristics of the three parents, they resemble somewhat more closely to the original mother plant Triticum (Photo. 1).
5. Most of the individuals of TperHRF₁ and TdurHRF₁ were almost sterile, but in extremely rare cases, some anthers opened and some grains were obtained in natural selfing (Table 5) and by sowing them in October 1958, many F₂ plants were raised.

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The lipid granule can not be found in the young cells. There are small lipid granules in the cells of the logarithmic phase, but large lipid granules in the cells of the stationary phase. The large lipid granule begins to change into spore from its center. This observation has been made by the methods of Heidenhain's hematoxylin staining and Möller's spore staining.
From these results, the author supposes that the lipid granule has some relation to the spore formation.

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