The ratio : number of deaths by cancer / total number of deaths was compared between the spas (Misasa - a radioactive thermal, Togo - a muriated thermal) and their neighboring villages in Tottori-prefecture, Japan. A significant decrease in the ratio was recognized in spas, especially in Misasa, compared the result not only with that of the neighboring villages but also with the ratio in total Tottori-prefecture
or the ratio in all Japan.
