Laboratory model experiments were made with the object of clarifying the vital states of Salmonellatyphi in urban water system and coastal sea water, in comparison with those of Salmonella paratyphi B and Shigella sonnei, by adding washed cells of these organisms at a ratio of 10-/ml to samples of sewage, riverwater, estuarine water and sea water. Their survival rates at the mean temperature of the sampleswhen collected were then observed.
Viable cells of S. typhi decreased in number as the time proceeded in each of the water samples. Almost no V-W and S-R variations were found during the period of survival. When the time (days) for reduction of initial population to 1/10 (T1/10) was used as the survival time, index T1/10 at temperaturesbelow 15°C (2.3-7.8) was significantly (P<0.01) greater than those at temperatures above 25°C (0.4-2.2) in each of the water samples used, and it became apparent that T1/10 is inversely correlatedclosely with water temperature. Correlation coefficients between water temperature and T1/10 were-0.73 in sewage, -0.96 in river water, -0.90 in estuarine water and-0.77 in sea water, respectively.It was difficult to ascertain any unique relation between survival and variety of water samples or pH, BOD, COD, C1-concentration, and the number of coliforms and other culturable bacteria, unlikewith the temperature of the samples. Growth or considerable prolongation of the period of survivalwas found in membrane-filtered water samples. Thus, the decrease of viable cells of S. typhi in untreatedwater samples is considered to be mostly due to a competition with-and predation by those micoorganismsnormally living therein, and intensity of these bactericidal actions is considered to be proportional towater temperature. These findings suggest that survival of S. typhi in urban water system is the greatestin the winter season and the most brief in summer, and that in winter when S. typhi is discharged in sewagethe organism may enter the coastal sea and may survive sufficiently long in sea water. With Salmonellaparatyphi B and Shigella sonnei, also, approximately similar results were obtained as with S. typhi, althoughthe test organisms showed a tendency for prolonged survival in the order of S. paratyphi B>S. typhi>S. sonnei. Possibility of transmission of S. typhi to man through shellfish which has been exposed to itin the sea was discussed.

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Spontaneously beating mouse hearts isolated from foetal mice are tested by comparing the convetionalmethod using petri dish with Rose's circumfusion system.
Foetal mouse hearts in organ culture are inoculated with coxsackie virus B, tested relating to theinfluence of virus on hearts, especially virus multiplication, changes of hearts beat, and histopathologicchanges of infectious tissue, and obtained the following results.
1) Long-term maintenance of spontaneously beating mouse hearts in organ culture by Rose'scircumfusion system is more effective than by the method using petri dish.For about 80 days, spontaneously beating hearts can be cultivated in perfect condition by the former.
2) Coxsackie virus B1, B2, B3, B4, B5 and B6 have multiplied in hearts tissue cultivated by Rose'scircumfusion system and they multiplied to high titers as compared with the method of petri dish.
3) The hearts inoculated with coxsackie B viruses of all types stopped beating early as comparedwith uninoculated ones.
4) In the pathologic findings in hearts infected with coxsackie virus B, coxsackie B3 produceda virulent and diffuse necrotic lesion, while coxsackie B6 did a mild and focal necrotic lesion.

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In the diagnosis of streptococcal infection, it is especially important to isolate group A streptococcusin relation to the prognostic consideration; rheumatic fever, acute glomerular nephritis and heart disease. And, the study was subjected on the hemolysis inhibition test by Kobayashi as a screening method inthe WHO Expert Comittee 1967. This study aimed to enhance the practicability of Kobayashi methodby dextrose disk.
The principle of Kobayashi method is based on the hemolysis inhibition by dextrose on the bloodagar but the minimum concentration of dextrose for this test is not quite clear. The results of this studyon the total of 550 strains of beta hemolytic streptococci including stocked and freshly isolated strainsin the field works indicate that 1.2mg per disk is most suitable for the screening of group A streptococcus.
In this test the strains to be tested were inoculated by stub method at 2 different places which are 2mm and 15mm distance from the disk. At the place of 2mm distance from the disk, the beta hemolysiswas inhibited but not at the place of 15mm distance.
This is a simpler and more reliable method for the hemolysis inhibition test of beta hemolyticstreptococcus. Moreover, in this test streptococcus could be divided into such 3 groups as: Group I: the hemolysis is strongly inhibited by dextrose (Group A, Lancefield) Group II: the pigment sedimentation due to dextrose is observed (Group B, Lancefield) Group III: no change in himolysis by dextrose (Other than Group A and B, Lancefield).

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[in Japanese]

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