In view of the relative importance of respiratory processes in virus-infected plants, it was considered worth to carried out biochemical analysis of dehydrogenase activity in leaves comparing with those virus-infected and the sound ones.
In the demonstration of dehydrogenase activity in extracts of leaf homogenates, 2, 3, 5-triphenyltetrazolium chloride (TTC) was employed by Thunberg techniques. Solutions containing the enzymes were prepared by fractional centrifugation from the green leaves of higher plants (tobacco. tomato, dean, and broad bean).
The crude enzyme preparation from broad bean reduced TTC without substrate and showed the same reducibility even if Nicotinamide (inhibitor of DPN-TPN-linked dehydrogenase) is added. However, the enzymatic activity of which was completely inhibited by malonate. The enzyme could not be purified by centrifuging×15, 000g except in the case of seedling of broad bean.
When tomato leaves were inoculated by TMV, dehydrogenase activity during infection did not show any detectable increase until four days after inoculation. In detached leaves of tobacco, closely allied to this, oxygen consumption by infected discs was found to be scarecely higher than the sound ones. In contrast to this, the examinations on bean leaves (variety Otenashi) inoculated by TMV, which produce local necrotic lesions on the leaf, revealed that not only the dehydrogenase activity but the oxygen consumption is greater than control.
This observation suggests the existence of essential difference between systemic infection and local infection by plant virus. With the aid of these findings, a brief discussion was devoted on the metabolic processes in leaves during virus infection.

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For searching on fate of the virus (HVJ) in fertile eggs, 10^4.5 EID₅₀ of the virus was inoculated into the allantoic cavity and infectivity and hemagglutinin titrations in several parts of the infected eggs were carried out at several intervals from 12 to 72 hrs after the inoculation.
Consequently, it was demonstrated as follows; 1) In early stage (12 hrs after infections), the viral growth in chorioallantoic menbrane and allantoic fluid was much more than in other parts. In following periode, the growth curves of the virus in above both sites were paralled with one another and it seemed to be so closely related with the case of influenza viruses 2) Although at 12 hrs after inoculation the titer in amniotic fluid was less than that in allantoic fluid and chorioallantoic menbrane, at 72 hrs it showed highest titers (10^9.8EID₅₀) throughout whole course of the viral development in this experiment. Also, it appeared that the viral growth curve in amniotic fluid paralled closely with that in the embryos The above mentioned facts seemed to be different from the case of influenza virus infection. 3) The ratios of infectivity and hemagglutinin titers in all the parts of the fertile eggs were calculated and their characteristic significances were discussed.

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The effect of chloramphenicol on the phage development of UV induced E. coli, K12 (λ) was investigated by the one step growth experiment and the quantitative analyses of protein and of DNA synthesis.
When chloramphenicol is added to the induced culture at any time between 40 and 60 minutes after induction (the minimum latent period of λ is 60 minutes), induced cells lyse prematurely and the mature phage particles are liberated. Introduction of chloramphenicol during the first 35 minutes, however, is followed by a consequence that the number of infective centers tested gives less than the number of treated bacteria. These results are in fair agreement with Delbrück's finding which has been ascertained by the technique of stopping phage growth and making the cells to lyse prematurely by exposure to the KCN. It is confirmed that chloramphenicol treatment inhibits the induced bacteria from further phage development-similarly to the experiments with strain B infected with T1, and that the mature phage particles begin to appear in induced bacteria at about 40 minutes after induction.
At the earlier stages of the phage development, the chioramphenicol inhibition is reversibly removed and its influence does not seem to be reserved when the drug is diluted out. Namely, the length of the latent period is prolonged as much time as one of the exposure to the chloramphenicol, and essential latent period is not affected by the additions up to 45 minutes after induction; there is no prolongation of latent period and bacteria burst at normal latent period, if induced bacteria are still later exposed to chloramphenicol. The average phage yield too is not influenced by the presence of chloramphenicol for a short period either at initial or terminal stage. However, a, marked decrease in burst size is noted with the interruption of phage development at the middle portion, i.e. in this case there seems to be a somewhat irreversible effect of chioramphenicol on the mechanism of phage develpment.
In a growing culture of K12, chloramphenicol at bacteriostatic concentrations depresses the both ribonucleic and desoxyribonucleic acid syntheses considerablly, but a lesser extent in comparison with the complete inhibition of protein synthesis. An identical suppression is also found in the DNA synthesis of induced bacteria, when chloramphenicol is added as late as 30 minutes after induction. In contrast, the chloramphenicol addition immediately after induction shows the complete inhibitory effect on the phage DNA synthesis, as on the protein synthesise Further more, the synthesis of phage DNA begins lately as equal to the affecting time of chioramphenicol when the bacteria are exposed to the drug for a given period after induction.
These results indicate that the DNA synthesis of the induced K12 requires the new metabolic system (s) which does not participate in the host DNA synthesis, and that some enzyme proteins constructing such system (s) are synthesized immediately after induction and are continued to be formed during the first half of the latent period. It seems more adequate in the “photorestorable phase” to be interpreted not merely as the conversion of the prophage into the vegetative state takes place, but also as the metabolic reactions for phage development are already initiated.

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A new virus-host system or ectromelia virus-Ehrlich ascites tumor cell system has been introduced. With this system the growth curve of this virus was showed in vivo and in vitro, and at the same time parallel morphological changes of these cells were demonstrated; adsorption, immigration, eclipse, latent period, multiplication, and liberation were suggested.
In vivo type B of the inclusion bodies (matrices) appeared at first six hours after the infection, and type A of these (Marchal bodies) fourteen hours. Then they increased more and more in number and in size. Eighteen hours after the infection oncolyses came in view. About three days later, the majority of the cancer cells disappeared as the result of oncolyses. Mitoses have been decreased or disappeared. The first step of growth cycle continued for ca, eighteen hours, and each following step about twelve hours.
Also in vitro the inclusion bodies and mitoses have been demonstrated. One-step growth cycle has been prolonged for two or three days. Type B of the inclusion bodies appeared on the second day of the incubation, they increased on the third day, and type A of the inclusion bodies appeared on the fourth day.
Quantitative studies on the interaction between the virus and the tumor cells have been done.
Type A and type B of the inclusion bodies had been described in the previous report of the author.

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Some problems in the immunity to infectious ectromelia were discussed in a previous report. In the present paper, the immunity was studied with special reference to relationships between the immunity to the systemic disease and that to the local lesion at the inoculated site.
In neutralization test, when a mixture of virus and homologous immune serum was injected intraperitoneally the neutralizing effect was measurably shown, while when injected plantarly local lesions developed with similar intensity as in controls in which only virus was inoculated. Then, virus, homologous immune serum, and the peritoneal fluid of mice were mixed and injected after incubated at 37°C for 2 hours and subsequently in an ice-box overnight. As shown in Fig. 1, local lesions caused by plantar inoculation were again similar as in the controls.
In order to know the virus-absorbing ability of immune serum in vitro, homologous immune serum was mixed with virus, incubated at 37°C for 2 hours and in an ice-box overnight, and then heated at 56°C for 30 minutes. The supernatant after a centrifugation in 12, 000 r. p. m. for 60 minutes was used for neutralization and complement fixation test. By this method no virus-absorption by immune serum was confirmed.
When mice surviving infectious ectromelia were reinoculated, they developed neither local lesions nor generalized diseases. In mice treated with U. V.-irradiated virus, local lesions by plantar injection were developed in a similar intensity as in controls, but no generalized diseases were observed. This result was confirmed by the titration of virus in the blood, liver and pad of the mice after infection.
Moreover, when mice were daily injected with immune serum in early stages after intraperitoneal infection with virus no systemic symptoms could be found, while local lesions were caused by plantar infection regardless of the serum injections.
From the results mentioned above it seems to be safely concluded that the systemic infection of mice with ectromelia virus could be protected by serum antibodies, whereas the protection of local disease at the pad could be obtained only after infection with live homologous virus and has no relation to the existence of serum antibodies. Therefore, the pathogenesis and immunity of these two types of diseases in infectious ectromelia should be separately considered.

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The author has obtained the following results through his study of HVJ (type sendai) conducted in the manner described below in comparison with influenza A (PR 8).
The growth of HVJ (type Sendai) on Zinsser's agar slant and in Maitland's culture flask (with chorioallantoic membrane) was thoroughly followed in terms of HA and EID₅₀, and the virus was cultured successively generation after generation on Zinsser's agar slant and was investigated on its infectivity to eggs and mice as well as on its hemagglutination titers in order to reveal the changes in the nature of the virus particles. 1) HVJ can be multiplied on Zinsser's agar slant and moreover, it can be successively cultured generation after generation. But a clear distinction observed between this virus and PR 8, is the fact that its HA negative periode is considerably longer than PR 8, especially when they were inoculated in a small quantity. 2) Both, HVJ and PR 8 cultured on Zinsser's agar slant fall in EID₅₀ titer and rise in HA titre in their first generation when inoculated in a large quantity. Consequently the ratio of EID₅₀ to HA drops considerably.
In view of these facts, it is clear that this culture contains many noninfectious virus particles. But it cannot be easily determined whether this virus particle is premature, incomplete or inactivated in natures IT seems probably that this is incomplete in its first stage of culture (2 to 3 days), whereas it will be mixed with inactivated virus particles in the last stage (4 to 5 days). 3) As mentioned above, HVJ cultured on Zinsser's agar slant contains many non infectious particles in the first generation. But if it is successively cultured generation after generation at an interval of two to three days, it becomes to possess a nature of a complete virus with rising EID₅₀, with comparatively lower HA and with the ratio of I to H being kept between 5-6. 4) The pathogenicity against mice of HVJ cultured generation after generation on Zinsser's agar slant is considerably lower in comparison with that of the egg passage virus even if their egg infective titers were kept in an almost epual values. 5) When cultured by Maitland, s method with chorioallantoic membrane as its culture tissue, HVJ was quite different either from influeuza A or B and was rather similar to NDV so far as their multiplication behaviour is concerned, because its latent period was considerably longer.

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The in vitro and in vivo effects of fluorides (sodium fluoride and sodium monofluoroacetate) upon poliomyelitis virus of Lansing strain were studied with white mice infected with the virus by the intracerebral and intraspinal routes.
Sodium fluoride had no effect on the polio virus in vitro at a concentration of 2500γ/ml (i.e. 0.25%) in physiological saline; or it had no effect on the polio infection of mice when it was administered in intraperitoneal injection of 35mg/kg per mouse.
Sodium monofluoroacetate showed an apparant inhibition of the infection of polio virus during the initial stage when it was administered in the intraperitoneal injection of 9mg/kg per mouse. Moreover, the time when the first sign of infection appeared was delayed in the treated mice. However, only a slight inhibition could be observed when sodium monofluoroacetate was administered in dose of 5mg/kg per mouse.
It appeared that the inhibitory action of sodium monofluoroacetate to the morbidity of poliomylitis produced by the intraspinal route was more effective than that produced by the intracerebral route.
Sodium monofluoroacetate at a relatively high concentration such as 2500γ/ml had no direct effect in vitro on the infectivity of poliomyelitis virus.
It was demonstrated with mice infected with polio virus either intracerebrally or intraspinally that sodium monofluoroacetate showed a definite initial depression on the rate of virus multiplication when it was administered one hour prior to the virus inoculation either in the administration in the dose of 9mg/kg or 5mg/kg.
The inhibitory effect on the multiplication of polio virus by sodium monofluoroacetate appeared a little more distinct with the intraspinal inoculation than with the intracerebral inoculation.
Throughout the present experiments, it was shown that the incubation period of the polio infection in mice was shorter in the intraspinal inoculation than in the intracerebral inoculation.
Biological and virological significance of the results obtained was discussed, and it was postulated that the reduced growth of polio virus as observed might be correlated to the accumulation of citrate associated with the intoxication by sodium monofluoroacetate, as well as to some other unknown factors.

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It is very difficult to obtain the ultra-thin section of tissue cultured cells.
It was found that:-
1. The coating of the coverglass, on which the cultured tissue would grow, with the chicken blood plasma facilitated the removal of the tissue from the glass substrate in the absolute alcohol in the course of dehydration.
2. The original tissue was excluded in the ethanol with the needle tip. The specimen embedded into the methacrylate, thereafter, entirely consisted of the new grown tissues.

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