In order to elucidate the internal structure of gallstones, the method of super soft x-ray photography was applied to the 374 cases of cholelithiasis, and a new classification of gallstones was made based on these photographs. This method has an advantage to make the internal structure and components of the gallstones clear without breaking them. By this method, all gallstones were classified into five types.
1. Monocentric radial stones.
2. Monocentric radial, lamellar stones.
3. Multicentric radial stones.
4. Cocentric lamellar stones.
5. Others.
The minute structure, especially the form and localization of calcium in the gallstones were detected in thin section of calculus using contact microradiography. (C.M.R.)
C.M.R. was concluded to be better to examine the arrangement of calcium than histochemical method which might add artificial changes to the preparation.