In order to analyse the mechanisms of host-parasite relationships in diphtherial infections, 4 strains of Corynebacterium diphtheriae isolated in Taiwan were first compared for their virulence by intradermal test in cortisone-treated and control (non-treated) groups of rabbits. It was found that #74 strain showed much weaker reaction as compared with other strains, i.e. #103, #78 and #69. This difference was apparent even after dilution of the inoculum to 10^-1 or 10^-2. In the dose-response curve, in which the amount of living bacilli (viable count) was taken into account, such difference in virulence was clearly observed. Therefore, the difference in virulence is not due to the difference in the number of viable bacilli present in each inoculum, but rather to the inherent ability of the individual bacillus itself to survive and produce toxin in the host.
In the cortisone-treated groups of rabbits and guinea pigs, the skin reaction was generally markedly weaker than in control groups. The erythema at the site of injection was almost absent, and if present, it was observed to form a ring-form halo around the outer edge of induration. The induration was also less in size and thickness, and ulceration was rarely observed in the cortisone-treated groups.
After intradermal injection of diphtheria bacilli, when the animals were not treated with a single injection of antitoxin to prevent premature death, the mortality of the infected rabbits and guinea pigs was not significantly different between the cortisone-treated and control groups. However, the positive rates of re-isolation of the diphtheria bacilli from regional lymph nodes and spleens of rabbits were significantly higher in cortisone treated than in control groups. Thus, the factors of parasite, i.e. inherent potency of the bacilli to survive and multiply in the host and toxin-producing ability, as well as the host factors such as amount of corticosterioids excreted, etc. seem to be the important determinants of diphtherial infection in man.

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Mycobacterium tuberculosis and Mycobacterium bovis were differentiated from other mycobacteria by their negative growth on salicylate-Ogawa medium and on nitrate medium. These two organisms could be separated by the niacin test, nicotinamidase test, and susceptibility to thiophene-2-carbonic acid hydrazide (TCH). M. tuberculosis showed a positive niacin test, showed a positive nicotinamidase activity, and grew on the TCH medium, whereas M. bovis showed a negative niacin test, showed a negative nicotinamidase activity, and did not grow on the TCH medium. If used singly, these three reactions had shown a few exceptions, but these exceptions were excluded by the combined use of the three methods. Thus, M. tuberculosis and M. bovis seemed to be identified by the above five in vitro tests. Remark: Salicylate-Ogawa medium-Ogawa egg medium containing 0.5mg/ml and 1.0mg/ml sodium salicylate. Nitrate medium-a modified Sauton agar medium, in which sodium nitrate was substituted for asparagine. TCH medium-Ogawa egg medium containing 10μg/ml and 50μg/ml TCH.

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From acetone-dried cells of C. albicans, we extracted the crude antigen with phosphate buffer solution (pH 7.2) containing phenol at concentrations of 45% at ordinary temperature (Fraction I), and from “cell. residue” with hot-water at 100 (Fraction II), and then further obtained a alkali soluble polysaccharide by use of 3% NaOH-extraction method under an atmosphere of N₂ from insoluble “cell-residue” (Fraction III).
The resulting crude extracts has been fractionated repeatedly with DEAE-Sephadex column, and a clarified Candida-mannan which showed a ultracentrifugically and electrophoretically single peak was obtained. In the fractions eluted from the column, there are two components of neutral and acidity fraction, and it has been ascertained that the later comprise a small amount of phosphorus.
Each crude fractions of F. I, II, III showed nearly similar activities on precipitin reaction, and a decrease of their precipitin titer on account of drastic extraction methods was not observed.
When Candida anti-serum was selectively absorbed with F. III-mannan, it was observed that the precipitin reaction of crude F. III expressed completely negative reaction and the precipitin titers were largely effected on their serological activities in the case of FI, II.

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Having an occasion to isolate B. anthracis from the pustule of a patient with cutaneous anthrax, biological characteristics of the new isolate as well as preserved strains were compared with those of B. cereus. As a result, negative results in both phenol phthaleine-phosphatase and urease activity and slow peptonization of milk with B. anthracis were strongly in contrast with the positive results in two tests and rapid peptonization of milk with B. cereus. While, sensitivity of B. anthracis to several penicillins is the simplest indicative o differentiate one from B. cereus.

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