The intratypic serodifferentiation test of types 1 and 2 polioviruses was investigated after Wecker's method. Variables in the test were examined extensively with type 1 polioviruses; these included animals to be immunized, immunization schedules, time of bleeding, temperatures of incubation for the test and criterion of the evaluation of the results obtained. It was proved that the modified Wecker test was applicable to the differentiation of Sabin vaccine-related types 1 and 2 poliovirus strains from wild poliovirus isolated in Japan before the mass vaccination with Sabin vaccine in 1961. It was confirmed that the vaccine-related strains showed antigenic drift from the original strains during human passages. Several problems concerning the serological differentiaton of polioviruses are presented and discussed.

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Effect of concentrated urea on JE virus was studied with a special view upon the structure of the virion. Urea concentration less than 2M acted reversibly to destroy the particles at 24 C in a wide range of pH between 7.2 and 10.0. At concentrations of urea higher than 3 M up to 8 M, the particles were disrupted irreversibly with a rapid loss of both infectivity and hemagglutinating activity. As for the action mechanism of 1 M urea on JE virus, it was demonstrated that the first rapid inactivation was completed within 10 minutes, then followed by the second step of slow inactivation. The latter was sensitive to increase of temperature in urea inactivation. Since the second step was diminished when 0.1 M 2-ME was added in the reaction mixture, this reaction might be a reversible one through free exchanging of the hydrogen bonds. Namely, 2-ME blocks free -SH groups which are functioning reversibly for reassociation. However, in the presence of 5 mM cystine-cysteine mixture, this inactivation was reversed apparently and the particle reassociation was proved by centrifugal analysis in sucrose gradient column. When 5 mM cystine-cysteine mixture was contained in a sucrose column, HA activity was recovered in the band of virion by possible reassociation of the smaller particles. From these results, we may conclude, as to the action of 1 M urea on JE virus, that the effect is partly reversible in denaturation of proteins and its structure.

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Enteropathogenic Escherichia coli isolated from diarrheal children and adults were studied. Twenty-two OK groups were set up as enteropathogenic Eschericha to include: O26: K60, O28a, 28c : K73, O44: K74, O55: K59, O86: K61, O86: K62, O111: K58, O112a, 112c : K66, 0119: K69, O124: K72, O125: K70, O126: K71, O127: K61, O86: K63, O128: K67, O136: K78, O143: Kx1, O144: Kx2, O146: K87, A-D (Alkalescens-Dispar) O1: K1, A-D O2: K1, A-D O3: K2, and A-D 04: K3.
1. Seven hundred and eighty-nine strains of the enteropathogenic Escherichia were collected from diarrheal children and adults. OK group O124: K72 greatly exceeded any other OK group and provided 196 strains (25 %) ; O136: K78 (12.1 %) ; O44: K74 (9.2 %) ; O144: Kx2 (9.0 %) ; O86: K62 (7.0 %) ; and O28a, 28c: K73 (6.6 %) were also found frequently. Each of the remaining 16 OK groups made up 5.0 % or below of the 789 strains.
2. Incidence of infection due to enteropathogenic Escherichia was established on the basis of 1076 hospitalized patients and 624 outpatients at the Municipal Ebara Hospital. The rate was compared with that of Shigella, Vibrio parahaemolyticus, Salmonella, and Entamoeba. Shigella and V. parahaemolyticus were the most frequent causative agents of dysentery in the hospitalized patients. However, the enteropathogenic Escherichia was isolated from 52 of the 458 cases which were Shigella and the vibrio free, and Salmonella from 20 other cases. When outpatients with gastroenteritis and enterocolitis were examined, enteropathogenic Escherichia was present in 44 of 624 cases, Shigella in 27, V. parahaemolyticus in 36, and Salmonella in only 4.
3. The 22 Escherichia were divided into two groups, shigella-like group included 028a, 28c: K73, O112a, 112c : K66, O124: K72, O136: K78, O143: Kx1, O144 : Kx2, and 4 serotypes of A-D group and generally originated from dysentery or enterocolitis. Most strains of these OK groups or serotypes were non-motile, and possessed biochemical properties resembling those of Shigella. The remaining 12 OK groups were included in the salmonella-like group, and they were isolated from cases of gastroenteritis. The former OK groups as well as Shigella produce keratoconjunctivitis in the guinea pig, while the latter 12 OK groups as well as Salmonella do not.
4. The necessity to draw attention to the possible role of enteropathogenic Escherichia in the etiology of diarrheal diseases in children and adults is discussed.

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“Lysosomal” fraction was obtained from 0.25 M sucrose homogenate of mouse lungs and spleens by differential centrifugation. The contents of lysosomes were separated from the fraction as the supernatant of centrifugation at 15, 000 g for 20 min, after treatment with Triton X-100 in concentrations from 0.05 to 0.5%. Viable tubercle bacilli, when incubated with the contents at 37C, acquired the lysosomal type of acid phosphatase activity and lost (or masked) the same kind of enzyme activity peculiar to the bacilli. Additional investigations using cell walls of the bacilli and by a cytochemical approach indicated that lysosomal acid phosphatase was bound on the surface of the bacilli. This result is compatible with our previous finding that “in vivo grown tubercle bacilli” isolated mechanically from infected mouse lungs have the host-originated acid phosphatase on their surface, and also with the current state of knowledge concerning phagocytosis, particularly the degranulation phenomenon. As the initial step of tuberculous infection, attachment of the lysosomal contents to tubercle bacilli engulfed into phagocytes was suggested.

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Diaphragm muscle specimens from 53 humans who died of various diseases unrelated to toxoplasmosis, and from 87 healthy dogs, and mixed specimens of diaphragm and abdominal muscles from 25 healthy cats were examined for the presence of Toxoplasma. The muscle specimens were digested with trypsin, and the digested materials were inoculated into the peritoneal cavity of mice (gpc strain) . Toxoplasma was isolated from 2 (3.8%) out of 53 humans, 11 (12.6%) out of 87 dogs, and 17 (68.0%) out of 25 cat muscle specimens. Eight (15.7%) out of 51 humans, 15 (17.2%) out of 87 dogs, and 15 (60.0%) out of 25 cats were HA test (Hanaki et al. 1964) positive at titers of 1: 64 or higher. The human cases, from which Toxoplasma was isolated, showed negative HA. In the cases of cats, the results of isolation of the parasite and the HA test were roughly correlated, but this was not the case in humans or dogs.

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A new gymnocephalous cercaria of echinostomous type was found from Parafossarulus manchouricus in Miyaki Prefecture, Japan. Its detailed morphology including the excretory system is described. This cercaria is closely related to Cercaria nuda Komiya, 1952 but differs from it in that it has sensory hairs on the upper edge of the oral sucker and the lateral side of the tail as well as in some other points. A new name Cercaria miyagiensis is proposed for it.

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Nine species of the cockroaches of the genus Rhabdoblatta found in Japan, the Ryukyu Islands and Taiwan were examined. The names of six species were revised and the remaining three were described as new species.

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