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In previous report, the hypothesis about the biocycle of Vibrio parahaemolyticus was discussed. In that hypothesis, contamination of sea-water and subsoil by Vibrio parahaemolyticis will be occured by folling out night-soil to sea water. When Vibrio parahemolyticus folled and reached to subsoil, at the bottom of the sea they get the pressre by the depth of sea water. In this report, we studied the effect of the presser by the depth of water to microbes. The ability of resistance to high pressure was studied, and the electron-microscopic structure under high pressure was observed. Critical pressure were ......... 2,000Kg/cm^2・150min., 2,500Kg/cm^2・60min., 3,000Kg/cm^2・30min., 3,500Kg/cm^2・15min., 4,000Kg/cm^2・10min., 5,000Kg/cm^2・5min., the electron-microscopic structure shown in Fig. 2-4. Tested microbes were isolated from night-soil, and the nature of them were identified with standerd strain of Vibrio parahaemolyticus except the only nature of growthing in 1% pepton broth. They have pathologenecity for mice