The morphological characteristics of the virus from standard passage, undiluted passage and the 10⁶ EID₅₀ inoculation were compared with each other.
In chorioallantoic fluid, in cases in which the EID₅₀/HA ratio is higher than 10⁶ (equal to standard passage), the diameter of the virus particles is constant, its distribution is normal and the width of the distribution is narrow. When the EID₅₀/HA ratio is low, where the presence of the incomplete form is dominant, the width of the distribution of the particle diameter is wide and the form of the distribution curve is skew.
In any condition of inoculations, many small sized particles are found in extracts of chorioallantoic fluid differently from the case of the chorioallantoic fluid. This finding is especially manifest in the case having low EID₅₀/HA ratio.
As these results, the author classifies the incomplete particles into three types:
1. Irregulary shaped particles larger than 120 millimicron.
2. Spherical particles which cannot be distinguished with complete particles, ranging 110-120 millimicron.
3. Irregularly shaped, small size particle smaller than 100 millimicron, maninly found in chorioallantoic membrane.
From the shape of distribution curve of the particle diameter and EID₅₀/HA ratio, the author considers the type 1 particle as the true incomplete form and the type 3 as immature form. The type 2 particles cannot yet be interpreted.

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1. The nucleic acid contents of purified and concentrated standard passage particles and undiluted passage (3rd passage) particles of influenza virus were compared.
2. In influenza virus particles the ribonucleic acid content (6.2%) is dominant than that of desoxyribonucleic acid (0.47%)
3. Between the nucleic acid content of these two passages there is no difference as desoxyribonucleic acid is concerned. (In standard passage: 0.47%, in undiluted passage: 0.39%). While, between the content of ribonucleic acid of these two, remarkable divergency is shown: the standard passage virus contains 3.3 times of ribonucleic acid compared with undiluted passage virus. (6.2%: 1.8%)
It is suggested that the infectivity of the virus is closely related to the ribonucleic acid content.
4. In the course of extraction of ribonucleic acid, the nucleic acid of the virus can not be extracted with cold perchloric acid until it is heated to 70°C.

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In the first report it was pointed out that the Zinsser's agar-slant tissue culture by using 10 day chick embryo tissue might be available for screening drugs effective on the inhibition of growth of Coxiella burnetii (C. b.) on the bases of fundamental investigations. In this report a minimal inhibition dose of each of antibiotics (chloramphenicol (CM), magnamycin (MM), achromycin (TC), streptomycin (SM) and penicillin (Pc)) and chemicals (diazin and para-aminobenzoic acid (PABA)) was estimated by adding various amounts of those drugs into the Zinsser's agar-slant tissue culture. The results were obtained as follows.
1. The growth of C. b. was inhibited to 100 per cent by adding CM in 5γ/ml to the culture medium. But C. b. proved to grow in the next passage on the culture medium without antibiotics. Accordingly it seems very likely that CM may not have coxiellicidal property but coxiellostatic.
2. 1γ/ml of TC gave a remarkable effect on both inhibition and delay of the growth of C. b. and its dose ranging 10-5γ/ml inhibited the growth of C. b. approximately to 100 per cent.
3. 10γ/ml of MM delayed and inhibited markedly the growth of C. b., and almost C. b. disappeared in the infected tissue by adding 15γ/ml of it.
4. The growth of C. b. was, to some extent, inhibited and delayed by adding 30-100γ/ml of SM to the culture. Such a phenomenon became marked by adding 200-400γ/ml of SM while 1000γ/ml of Pc allowed C. b. to grow well like the control without antibiotic.
The effectiveness of antibiotics and chemicals mentioned above may be compared as follows: TC>CM>MM>SM>Pc.
5. No evidence was obtained for C. b. to become adapted or resistant to CM after 7 passages on Zinsser's medium containing 5γ/ml of CM.
6. The growth of C. b. could not be inhibited on the culture added diazin to 2mg/ml. Such a test may be available for classification of C. b. from psittacosis virus group. 2mg/ml of PABA proved to be sightly effective on the inhibition of growth of C. b.. It may be useful for separating C. b. from rickettsia.
7. The effectiveness of TC and MM had no remarked tendency to fall in both medium groups preserved for 1 day at 37°C and for 1 day at 37°C and then 14 days at room temperature.
8. 20γ/ml of TC added to the Zinsser's medium allowed chick embryo cells which were cultivated for 8 days at 37°C to grow well like normal chick embryo cells in the stational culture medium in the next passage.

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Several characteristics of HVJ., Z strain, not described in the previous report were presenting here.
1. Hemolytic action was revealed when Z virus was eluted from fowl red blood cells. The intensity of the hemolysis increased with the furtherance of the virus concentration.
The hemolytic activity could be blocked with the homologous immune sera and treatment of the virus with formaline showed a reduction of the hemolytis. The inactivated virus obtained as a result of the destruction of the enzyme activity by heating revealed no hemolysis.
The intensity of the heinolysis was compared with the infected allantoic fluid and purified virus suspension in buffered saline. The hemolysis of the purified virus was stronger than the infected allantoic fluids which had the same titer with the hemagglutinating activity. The hemolytic activity was hightened by adding a small amount of ethylene diamine tetraacetate disodium or sodium citrate.
To get the maximum hemolysis in the infected aflantoic fluids 40 to 50 times as much EDTA as the purified virus suspensions was required.
The hemolysis was blocked by adding calcium chloride. The normal allantoic fluids inhibited the herolysis also.
2. Multiplication of the Z virus in chick embryos was held in check when it was injected with the active or irradiated influenza viruses, either simultaneously or at different times.
a) About 1 EID₅₀ of the active Z virus was excluded by the succeeding inoculation of the irradiated Lee virus of 100 EID₅₀ equivalent.
b) The active Lee virus and Z virus were mixed in ratio 1:1 and the mixtures was injected into chick embryos in dilution of 10^-1 and 10^-3. In the first mixture, the Lee exceeded the Z. In the second mixture, the reverse wsa true.
c) The Z and PR8 strain were mixed in varying proportions. The data showed that the Z virus and PR8 virus carry on interference between the two viruses, and under certain conditions both the X virus and PR8 strain can be multiplied simultaneously.

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The method of back inoculation in monkeys or man has been used heretofore to determine whether there has been propagation of measles virus in egg cultures. The virulence of this virus however readily become reduced by passage through eggs so that it is almosst impossible to detect whether propagation has taken place in each individual egg. The authors therefore conducted studies on the method for detecting propagation of the measles virus in the egg culture. Propagation of measles virus was accurately determined by the interference phenomenon with a hemagglutinating virus (the mumps virus was found to be most suited), neutralization of the interference phenomenon with immune measles serum and the complement fixation reaction, with the culture material as the antigen.
As stated previously, the egg cultured measles virus becomes almost avirulent and intranasal inoculation of this active virus imparts immunity to children who have not been infected previously with measles. It appears as if immunization of measles has been successfully attained but the number of cases is small so a conclusive statement must be with held until the reproducibility can be further verified.
This paper will be published in English in the Med. J. Osaka Univ. Vol. 6, No. 3-4.

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We have found a heat susceptible character of the h mutant derived from the Kr(h) strain of S. sendai (S. 71 strain) phage.
This character always accompanies the h character in the mutation (h)⇔h.
On the other hand this character can be introduced into the progeny of a cross with h⁺.
Therefore it can be presumed that the genetic factor contorolling the heat sensitivity of this Kr phage may compose a complex with the gene controlling the h characte.
Experiments concerning the problem whether these two loci can be separated or not are still being carried on. There have been observed several experimental results, which can support indirectely the possibility of the separation of these two loci.
We believe that the extremely high susceptibility of this virus can at least allow fluther investigation with respect to the heatsensitivity of the bacterial viruses.

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1. When S₄ bacteria were superinfected with temperate phage s₂ which bears a close relationship serologically to the carried phage s₄, a stable doubly lysogenic strain of S₄ was successfully odtained experimentally.
2. From the culture of this bacterium a new type of phages possessing exchanged characters of both parents was obtained in addition to both parents s₂ and s₄. Under the assumption that these new type viruses (r₁ and r₂) resulted from the recombination of s₂ and s₄, the mechanism of the recombination of viruses from doubly lysogenic strain has been considered.
3. The above recombinants r₁ and r₂ resulting from genetic exchange between s₂ and s₄ possess the characters of each of the parents in plaque morphology, host-range, etc, and moreover the factor determining O[I] antigen. It may be, therefore, concluded that the factor controlling the O[I] antigen of bacteria is situated inside the gene constitution of phage.

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