It has been discovered by Nakagawa and Kodama that FA strain of mouse encephalomyclitis virus agglutinates chicken red cells at 4C when 1.5% CaCl₂ solution is used as a reaction medium. The present study concerns the purification and concentration of the virus hemagglutinin by application of the properties of the virus.
Therefore, purification of the virus hemagglutinin by means of adsorption to and elution from erythrocytes was attempted. From the result obtained, this procedure was an effective and simple method as in the case of GD VII virus and Influenza virus. Ether extraction of crude, also, is a simple method for removal of nonviral nitrogen. In order to yield more purified hemagglutinin of FA strain, methanol and acetone precipitation methods were employed after ether extraction of virus material and elution of virus from blood cells.
The results obtained indicate that a good yield of hemagglutinin of FA strain is acquired by elution from precipitants produced by adding acetone to give a final concentration of 30% to the materials, obtained after extraction by ether and adsorption to and elution from erythrocytes, and keeping the mixture at 4C for 3 hours with occasional agitation.

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The authors have investigated the effects of Contomin (Chlorpromazine) and glucose on the propagation of the GDVII strain of mouse encephalomyelitis virus in tissue culture of mouse brain and obtained the results as follows. 1) Contomin decreased the level of metabolism of the brain tissue, however, it had no influence on the propagation of virus up to the concentration of 0.05mg/cc. 2) Glucose was an important source of energy in the tissue culture of brain and it increased the metabolism of the brain tissue. However, the propagation of the virus in a definite period was not affected with or without glucose.

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The author has investigated the effect of Contomin (Chlorpromazine) on the susceptibility of mice to mouse encephalomyelitis virus (GD VII strain) and obtained the results as follows. 1) In the case of the intracerebral inoculation of virus, the susceptibility to virus was not affected by artificial hibernation of 15 hours or less which was induced at the time later than 12 hours of inoculation. But the susceptibility was increased by artificial hibernation which was induced immediately before and after inoculation of virus. 2) The susceptibility increasing effect depended on the increase of the receptivity which allows the multiplication of virus. 3) Hypofunction of reticuloendothelial system was not observed in the mice maintaining such a level of artificial hibernation as done in this experiment. 4) In the case of the intraperitoneal inoculation of virus, the susceptibility was not increased even by artificial hibernation which was induced immediately before inoculation of virus. 5) Change of the susceptibility of mice under artificial hibernation, which was observed in this experiment, depended on the effect to the probability of establishment of virus-host system and the increase of local stationability of virus seems to have an important role on that effect.

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The author made some discussion and experiment on the method of biological assay of virus, assuming that the individual sensitivity of experimental animal is normally distributed against the logarithmic dosis of infective viral agent.
A normal regression line, which was estimated most likely from the values of experimental probits of the ratio of reaction at various doses of virus, was, adopted as an approximation of the linear relationship between the logarithmic dosis of virus and the value of probit of corresponding population. A method was proposed to test the significance of the difference of gradients - i.e. square root of the reciprocal of the variance of sensitivity - of the two experimental normal regression lines which were obtained from the two series of experiments. This method was applied to the estimation of the quantity of the influenza virus, WS strain, by infecting mice, fetile hen's eggs and Li-Rivers' procedure. And the last method showed the smallest value of variance of sensitivity.
It was concluded that the cultivation method of Li and Rivers is, especially because of its higher reproducibility, equally or more useful than mice and fertile hen's eggs for the determination of fifty per cent effective endpoint of influenza virus.

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The author, assuming that the individual sensitivity of experimental animal is normally distributed against the logarithmic dosis of infective viral agent, proposed methods for determining fifty per cent endpoint and its confidence limit and for testing the significance of the difference of two fifty per cent endpoints, and applied them to the experiments of influenza virus cultivated with the method of Li and Rivers.
A normal regression line, which was estimated most likely from the values of experimental probits of the ratio of the reaction at various doses of virus, was adopted as an approximation of the linear relationship between the logarithmic dosis of virus and the value of probit of corresponding population. Fifty per cent endpoint was estimated as an intersection of virus axis and regression line. Confidence limit was estimated as intersections of virus axis and envelopes of regression lines which correspond to the points of borderline of the confidence ellipse of the two variables - gradient coefficient of the regression line and the intersection of probit axis and regression linc. Lastly a method for testing the significance of difference of two fifty per cent endpoints was given, by assuming that, though the fifty per cent endpoints are not equal, the gradient coefficients of the two different regression lines are equal since both of them were concerned with the same strain of virus and with the same method of cultivation.

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In the neutralization experiments of a polyvalent temperate phage. β strain, using its specific anti rabbit serum, there observed two different neutralization curves by using two different indicator strains. That is, the valence for Shigella flexineri type 5 (Komagome A strain) was neutralized at a faster rate than the valence for Sh. flexineri Variant Y (Komagome BI strain). Neutralization velocity constant of β phage assayed on Komagome BI strain was about 60-80 min.^-1, whereas that on Komagome A strain was about 300 min^-1.
Several kinds of experiments were designed for its reason and it was concluded that this phenomenon due to the heterogeneous antigenic structure of each β phage particles.

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1. It was confirmed by complement fixation and hemagglutination inhibition tests of sera or isolation of virus from spinal fluid that six patients from July 1954 to September 1955, had mumps meningoencephalitis.
2. Only one of these 6 patients died on the 3rd day of illness, but the others recovered from the illness.
3. The author succeeded in isolating virus from spinal fluid of one case with clinical parotitis and meningoencephalitis. This spinal fluid was harvested on the 5th day of illness and agglutiinated human and chicken red blood cells.
4. The virus isolated from the spinal fluid was identified with mumps virus serologically and biologically.
5. Mumps complement fixation and hemagglutination inhibition tests were carried out on sera from 34 patients in 1955, supposed Japanese B encephalitis, but from whom sera were negative in the complement fixation test of Japanese B encephalitis. It was not confirmed that they suffered from mumps meningoencephalitis with exceptional 2 patients, who had parotitis and were positive in serologic tests with mumps virus.

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Thin sections of the epithelial layer of rabbit cornea were needed for the electron microscopy of the intracellular form of vaccinia virus and herpes simplex virus multiplying in the infected rabbit cornea.
It was very hard to obtain consistently the thin sections of the epithelial layer only of rabbit cornea by using the usual method in which all the cornea sliced into small pieces were embedded into the embedding material and then cut.
It was found that it was very easy to obtain the thin sections of the epithelial layer only, if it was stripped from the proper layer of cornea prior to embedding into the methacrylate monomer.

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