In the study of nutritional requirements of leptospirae, a basal medium containing asparagine, group B vitamins, glucose, etc. was developed. The growth of pathogenic leptospirae, Leptospira canicola Utrecht and L. icterohaemorrhagiae Mikawajima, were obtained in the basal medium supplemented with dead cells of mycobacteria, particularly of Mycobacterium smegmatis and M. phlei, in place of rabbit serum. The growths were or nearly equivalent to that obtained by the medium containing rabbit serum. When mycobacterial cells were removed by Seitz or Millipore filtration from their culture medium, leptospirae did not grow. It was believed that the growth supporting factor for leptospirae was closely associated with mycobacterial cells, and that the factor did not readily diffuse into the surrounding medium. The factor was heat-stable. The addition of rabbit serum to the medium containing, mycobacterial cells did not particularly increase the number of leptospirae cells. No other microorganisms was found to be superior to mycobacteria in growth supporting activity for leptospirae.

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Using the International typing phage 80 as the transducing agent, it was confirmed that the chloramphenicol-resistance can be transduced from a highly chloramphenicol-resistant strain of Staphylococcus aureus to sensitive strains of Staphylococcus aureus as well as Staphylococcus epidermidis.
In the case of Staph. aureus, about 46% of the test strains were competent recipients of the CM-marker, and the incidence of transduction was higher in strains of phage group I than those in the other phage groups. Transduction frequencies varied from 10^-7 to 10^-8. In the case of Staph. epidermidis, abaut 35% of the 23 strains used were competent to serve as the recipient of CM-marker.
Joint transduction of the penicillinase production, mannitol fermentation and coagulase production was not observed.

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1. A number of protection tests performed using several mouse strains were analyzed statistically.
2. Mouse strains were evaluated in respect to the possession of a considerably high sensitivity to infection against virulent pertussis organisms, relatively high regression coefficient, and differentiating ability of the vaccine's potency.
3. A possibility that mice may manifest their immature immunity to the challenge infection 10 days following the immunizing injection is discussed.

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The fine structure of hyphal cells of Aspergillus niger has been studied by means of electron microscopy of ultrathin sections. Permanganate fixation of the hyphae, especially in combination with uranyl nitrate, is far more effective in preserving their detail structures and enhancing the general contrast than osmium tetroxide fixation. The examination of the vegetative hyphae of mold reveals a considerably complicated and differentiated organization similar to that of higher organisms. Among yeasts and molds, A. niger is considered to be one of the fungi which possess a higher standard of differentiation in cell structure.
Well developed double-membrane strands, resembling the endoplasmic reticulum previously described in both animal and plant cells, are much noteworthy as a peculiar structural element of the mold. These strands may be connected to the other membranous structures scattered within the cytoplasm, nucleus, mitochondrion, vacuole, and cytoplasmic membrane. A spherical electron-dense granule, called a peripheral or septal body found in hyphal cells of certain dermatophytes, is also demonstrable at the peripheral end of A. niger hypha. This body is an important organelle of filamentous fungi consisting of septate hyphae in addition to the septal pore.
The other fundamental structures, usually seen in fungal cells as call wall, cytoplasmic membrane, nucleus, mitochondrion, storage granule, and vacuole, are also observable in the vegetative hyphae of the mold.

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Vibrio cholerae, Inaba strain, were cultured on an agar medium for 36 hours, and the spherical granule at the root of the flagellum of the cells was observed electron microscopically. The electron micrographs of the negative stained specimens revealed this to be a characteristic isolated granule that can be distinctly distinguishable from the cytoplasm because it has a thin unstained membrane or boundary around it.

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The effect of heterologous antiserum and complement on glucose metabolism of rat ascites tumor cells was examined to clarify the mechanism of the cytotoxic effect of antibody.
1. Lactate-production of the target cells was inhibited by the cooperation of antiserum and complement, while no inhibition was observed when the cells were subjected to either antiserum or complement alone. The inhibition of lactateproduction was observed under both aerobic and anaerobic conditions. No effect of the antiserum and complement was observed on the oxygen consumption of the cells.
2. The amount of antiserum necessary for the inhibition of lactate-production of the cells was determined in the presence of a definite amount of complement, and it was found that the degree of inhibition was not in parallel with the concentration of antiserum beyond a certain threshold. On the other hand, a parallelism was observed between the amount of complement and the rate of inhibition of lactateproduction when different amounts of complement were added to a definite amount of antiserum.
3. Similar inhibitory effects of the antiserum and complement on lactateproduction of the cells from glucose, fructose-1, 6-diphosphate, and pyruvate suggested that the inhibition occurred toward the final step of glycolytic process of the cells.

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