In the previous reports, abnormal phosphorous metabolisms were observed both in the stunt virusinfected rice plant and the virus transmitting-green rice leafhopper. This paper deals with the results obtained from the researches on the incorporation of P³² into the abnormal phosphorous metabolisms.
(1) The incorporation of P³² into various phosphorous fractions of rice plant or green rice leafhopper is lower as affected with the virus (Table 1-2).
(2) The autoradiograms on the incorporation of P³² into RNA and DNA show no difference between healthy and diseased rice plant or nonviruliferous and viruliferous leafhopper, as infected to the rice stunt virus (Fig. 1-2). The radioactivity of P³² in RNA-P of the diseased plant shows no difference from the healthy, and the radioactivity in DNA-P of the diseased is higher remarkably. But the radioactivity in RNA-P or DNA-P of the viruliferous insect is always found on higher level than that of the nonviruliferous.
(3) The acid soluble phosphorous compounds of the plant and the insect were fractionated by the method of LePage and Umbreit. The amounts of phosphorous contents and the radioactivities in the various fractions show no consistent difference between the healthy and diseased plant or the nonviruliferous and viruliferous insect (Table 3-4 & Fig. 3-4).

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This paper deals with the results obtained from the qualitative and quantitative researches on changes of organic acids in TCA-cycle members, sugars and nitrogen compounds in green broad winged planthopper as viruliferous with the dwarf disease virus of Satsuma orange.
(1) No change is recognized in pyruvic and citric acids of the viruliferous planthopper, but its succinic acid decreases in weight considerably (Table 1).
(2) The host plant shows that total and insoluble sugars decrease in weight, though reducing and soluble sugars slightly increase, as infected to the disease (Table 2). But all sugars of the insect vector increase in weight remarkably as viruliferous with the virus (Table 3).
(3) The amounts of soluble nitrogen compounds increase in weight but total and protein nitrogen compounds decrease in the insect vector as well as the host plant, accompanied with infection to the virus (Tables 4-5).
(4) The amino acids in the host and the vector are detected by means of the ordinary two dimentional paper-chromatographic technique (Figs. 1-2). In the amino acids in the fraction extracted with ethyl alcohol, 14 acids (viz. cystine, aspartic acid, etc.) are recognized both in the healthy and diseased plant, and 12 acids (viz. aspartic acid, glutamic acid, etc.) are found in the nonviruliferous as well as viruliferous planthopper. In the combined amino acids in the residue extracted with ethyl alcohol, there is no difference between viruliferous and nonviruliferous planthopper, but the diseased plant has unknown Ninhydrin sensitive substances in addition to 11 acids of the healthy plant. The unknown spots might be alanin-like substances (Table 6).
From the results mentioned above, it may be suggested that the examined planthopper has an abnormality in the metabolisms of respiration, protein and carbohydrate.

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Salmonella anatum was lysogenized with a converting phage ε¹⁵. The resulting S. anatum (ε¹⁵) was infected with another converting phage ε³⁴ (m.o.i.=2.5), and the pattern of segregation of non-ε³⁴-carrying progenies from ε³⁴-infected cells was analyzed both by mass cultures and by single clone experiments. Both presented evidences that non-ε³⁴-carrying progeny cells were segregated out from ε³⁴-infected cells, but the segregation was to only a slight extent, suggesting that the phage ε³⁴ becomes an established prophage more easily and more quickly than the phage ε¹⁵.

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When S. anatum (ε¹⁵) was infected with temperate phage ε³⁴ or even with its virulent mutants, O antigen 34 appeared on the infected cells within 30 minutes. It indicates that the formation of the new character, antigen 34, was carried out even in cells which are destined to lysis. The mutation from temperate to virulent proved not to be related to the mutation in converting abilities.

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In the past, all strains of Japanese B encephalitis (JBE) virus were thought to be antigenically the same. In 1954, Dr. Hale, however, described that the strains isolated in Malaya were not all the same but some antigenical differences were recognized among them. It was also suggested by Dr. Ogata that the antigenicities of the two Japanese strains, Nakayama and G-1, were found to be different from each other on the basis of cross-challenge test in mice, the former being isolated in 1936 and the latter in 1949. In order to determine whether or not the immunological differences might exist between those two strains, attempt was made to compare each other antigenically by means of cross-challenge test in mice checked weekly after the immunization on one hand, and on the other hand, by means of hemagglutination inhibition (HI)-, complement fixation (CF)-and neutralization-tests on pooled sera weekly collected from mice immunized with either virus. As a result, the mice immunized with Nakayama gave much higher resistance against challenge with the homologous strain than the heterologous G-1 strain within 4 weeks after immunization and the same trend, though it was slight, was observed in immunized mice following challenge with homologous or heterologous strain. Such antigenical differences were found, to some extent, between both strains by HI-, CF- and neutralization-tests on sera collected weekly from the immunized mice. As they did not give so clear cut result as the cross-challenge test, in the next study, sera taken from guinea pigs on every 2 days within 2 weeks after intracerebral inoculation with Nakayama or G-1 strain were examined for strain specificity. Sera taken on as early as 5 days after infection were found to have only strain specific antibodies.
Such phenomena as mentioned above were not caused by contamination of the strain with the other viruses sometimes encountered in a colony of mice, because both strains used were proven to be sensitive to desoxycholate and not to be precipitated by protamine sulphate. Furthermore, the antigenic structures of both G-1 antigens prepared front infected mouse brain at the 7th and the 196th passages were found to be almost the same.
This fact strongly suggested that G-1 strain antigenically different from Nakayama might not be a laboratory product during many passages from brain to brain, but could exist in situ in nature.

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In the course of the studies on the i mutation of polioviruses it was found unexpectedly that mutants of poliovirus, forming minute plaque-m mutants were selected in some series of the serial passages of type 2 poliovirus (MEF-1) in tissue culture. Similarly m mutant of type 3 poliovirus (Saukett) was also obtained.
Selection of m mutants occurred usually in the course of several passages in tissue culture, but the factor or factors responsible for the selection of the m mutants remained undetermined.
The plaque size of m mutants was less than 0.5mm in diameter in HeLa, FL and monkey kidney cell monolayers, and certain factors such as PH and amount of agar overlay did not influence the plaque size.
m mutants were neutralized specifically by antiserum prepared against the respective m⁺ wild type viruses.
No apparent differences in both the cytopathogenic effect and the pattern of growth were observed between m⁺ and m mutants.
m mutants, after being purified repeatedly by limiting dilution technique, were proven to be stable through rapid serial passages in tissue cultures or mice.
m mutants of type 2 poliovirus were virulent for mice but a few of them were found to be less virulent than the wild type m⁺ virus.
m mutant, isolated after serial passages in tissue culture with inhibitory normal bovine serum, was found to have i character as well as the back mutant m⁺ i, obtained from the m i mutant. Furthermore i m mutant was obtained from i⁺ m mutant through serial passages in tissue culture with medium containing inhibitory bovine serum. Therefore it may be concluded that i and m mutation can occur independently from each other.

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1. Non-mouse-adapted vaccinia can produce the specific complement fixing antigen, but not mature virus in the Ehrlich Ascites tumor cells.
2. IHD strain of vaccinia produces the cytoplasmic inclusion body, the C.F.A. and mature virus in the cells.
3. In this system, the viral antibody can supress the inclusion body and C.F.A. formation.

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1° L'immunsérum contre le virus de la fièvre de la Vallée du Rift a pu être saturé avec le virus homologue.
2° Avec le virus de la fièvre de la Vallée du Rift, le phénomène dit de dilution se fait remarquablement. Le taux de la réactivation du virus a été de 10% lorsque le mélange a été immédiatement dilué. Le taux n'a été que de 1% lorsque la dilution a été pratiquée après 24 heures.
3° La réaction du neutralisation de ce virus est négative, quand le mélange est injecté immédiatement après la préparation par voie intracérébrale. Une incubation de 24 heures du mélange a rendu positive la réaction.
4° Les résultats nous suggère la fixation in vitro des anticorps au virus.

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Multiplication of Cal 10 strain of meningopneumonitis virus (MPV) in vitro was studied using strain L cells as host cells. Relationships could be established among the developmental cycle of virus determined by infectivity titrations, the viral alterations within the cells tinctorially with light microscope, and the submicroscopical structures of various developmental forms and intracellular components, containing matrix, associated with virus under the electron microscopy.
It was found that a sharp decrease in infectivity titer of cell-associated virus during the first 18-20 hours was followed by an increase in titer 22-23 hours after infection, and then a few hours leter, free virus began to increase.
The yield of MPV in a L cell, estimated from the maximum titer of free virus to the number of infected cells, was about 600 mouse LD₅₀ per cell.
It was showed with Macchiavello's stain that hundreds of red stained particles (identified the elementary bodies at the terminal stage of development) were adsorbed on the cells soaked in a suspension of MPV for 2 hours, and a few hours later, most of these particles invaded to form a group in the central region of cytoplasm, where one or more blue stained large particles (initial bodies began to develop 8 hours after infection.
Some particles with elementary body-like structures attached to the cell membrane soaked for 2 hours and several similar particles in the cytoplasm (5 hours after infection) were photographed using ultra-thin sectioning. Single large body enclosed by a intracytoplasmic vacuolar structure (tinctorially invisible matrix) were the first appearance of developmental form of MPV, observed with the electron microscope.
Large bodies in the inclusion (20 hours) often presented a morula-like appearance showing their increase in number by segmentation. A number of elementary bodies (intermingled with various developmental forms) were observed in the inclusion at the initial stage of increase in titer (24 hours after infection).
And it was found that the titration of MPV in strain L cell based on the cyto pathogenic effect was not only sensitive and reliable but also available with ease.

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