and Sasaki Institute, Sasaki Foundation*2) Synopsis Donryu rats bearing ascites hepatoma AH-21 were examined microscopically at frequent intervals to study the mechanism of hemorrhage in ascites. A reaction of possibly immunological nature was found in such rats with the appearance of reactive foci showing capillary dilatation within 48 hours from tumor inoculation coinciding with tumor invasion in the mesentery and omentum. Hemorrhage was started from these foci and increased by further injury

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... caused by tumor breakdown. Splenomegaly was also evident. Hemorrhage was slight after treatment with cortisone. The appearance of hemorrhage was found to depend on the dose of tumor inoculum. The importance of hemorrhage as an indicator of the severity of such reaction in ascites tumor was discussed.