Utilizing trypsin and alkaline degradation methods the separation test of hepatoma islands was performed to evaluate mutual adhesiveness of ratascites hepatomas. The calcium contents of tumor cells were also studied by means of chemical analysis and microincineration method. Calcium contents were estimated in human cancer tissues and invasive omental tumors of ascites hepatomas by the microincineration method. It was found that intercellular adhesiveness was extremely important in determining the histologial architecture of the tumor and that it could be evaluated from their calcium contents. In addition, motility and permeability of tumor cells were studied, as they are possibly factors closely related with calcium contents or intercellular adhesiveness. The interrelationship between histological pattern and invasive growth, metastatic spread and drug susceptibility of tumor was also discussed.