This paper is concerned with new findings in the comparative study of the genera, Bacteroides, Sphaerophorus and Fusobacterium. Victoria blue 4R and barbiturates were found to be effective in differentiating the genera by their discriminative inhibition of the growth. A new character, glutamic acid decarboxylation, was found in Bacteroides but neither in Sphaerophorus nor in Fusobacterium. The procedure for this test was presented. In the classification of newly isolated fecal strains this test and other differential features were compared. An improved method for the threonine deamination test was reported. The use of these characters and tests would be a step in the improvement of the present incomplete classification of gram-negative anaerobic non-sporulating rods.

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Conjugal transfer and autonomous replication of some episomes occurred normally in a recombination-deficient (Rec^-) mutant of Escherichia coli K-12. Transduction with phage Plbt of an R factor also occurred normally in this Rec^- mutant, but complete or abortive transduction with Plbt of chromosomal genes did not occur. In contrast, transduction of galactose genes by phageλdg occurred in the Rec^- bacteria as frequently as in the Rec⁺ strain. It was shown that phage Plbt does not grow at all on the Rec^- bacteria. Recombination between two different R factors, two mutants of phage y and two mutants of phage T4 occurred normally in the Rec^- bacteria, but did not give a Rec⁺ phenotype to the host bacteria. Colicinogenic factor I made the Rec^- host bacteria more resistant to ultraviolet light but the colicinogenic strain was still infertile in the crosses with the Hfr Brains of E. coli K-12.

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5-Iododeoxyuridine (IUDR) inhibited production of infectious polyoma virus in mouse embryo cells and mouse kidney cells in culture. Deoxythymidine reversed its effect. IUDR did not inactivate infectivity of free virus particles. IUDR did not prevent adsorption and penetration of polyoma virus to cells. The events sensitive to IUDR treatment occurred at around 20 hours after infection. The cytopathic effects of polyoma virus, including emergence of DNA containing-inclusions in the nucleus, were observable in infected cells in which viral replication was completely arrested by IUDR. It was shown by fluorescent antibody technique in infected mouse embryo cells and by complement fixation test in infected mouse kidney cells that IUDR inhibited completely the synthesis of viral antigen. No virus-like particles were demonstrated in the IUDR-treated infected-mouse kidney cells by electron microscope examinations.

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A comparative study of the tuberculin potency and reactivity to TAP and PPD-S was made in humans and guinea pigs. A comparison of reactions elicited by TAP and PPD-S was made in two groups of guinea pigs previously inoculated with killed bacilli or with living bacilli. The tuberculin reactions produced by TAP and PPD-S in human beings was studied in school children from rural districts. These children were divided randomly into three groups and each group was given a different amount of TAP and PPD-S. The results obtained are as follows: (1) While relative potency of TAP was relatively much weaker than PPD-S in guinea pigs sensitized with tubercle bacilli, in human beings the tuberculin potency of TAP was approximately 1/2 or 1/3 that of PPD-S. (2) There was a marked difference in the tuberculin reactivity to TAP and PPD-S between guinea pigs immunized with killed bacilli and guinea pigs immunized with living bacilli.

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Formalin-inactivated, alum-adsorbed measles vaccine was readily prepared from virus grown in calf kidney cell culture infected with the Sugiyama strain of measles virus which had been adapted to this cell culture. The vaccine induced no side reaction of any consequence in vaccinated children, but demonstrated antigenic capacity in children as well as guinea pigs, comparable to that of currently used killed measles vaccines prepared from virus grown in monkey kidney or chick embryo tissue cultures. The host system employed for the preparation of this vaccine has an advantage over monkey kidney or chick embryo tissue cultures which are currently used for manufacture of killed measles vaccine. Bovine kidneys are much easier to obtain and cultivate. Of im-portance is the fact that calf kidneys are practically free of latent virus, whereas monkey kidneys and chick embryos frequently harbor latent viruses.

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One hundred and twenty-one children showing symptoms of acute upper respiratory disease were bled during a period of nine months, from winter to summer, for detection of complement-requiring neutralizing (CRN) antibody against herpes simplex virus. Six of the cases, all from children under the age of 13 years, were unequivocally related to herpetic infection as evidenced by the presence of anti-herpes CRN antibody. During the same period, 144 other children who were normal healthy or suffering from unrelated non-febrile diseases were tested as controls; anti-herpes CRN antibody was not detected in any of them. Further, the age distribution of individuals with antibodies was compared between patients in the acute upper respiratory disease group and the control group. This analysis showed that approximately 5 to 7% of the acute upper respiratory diseases in the young children in this study would be attributed to herpetic infection.

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