[Composition of biliary calculi and possible causes of their formation]

The ingredients and chemical content of 135 biliary calculi from 120 operated patients was studied roentgenostructurally, with infra-red spectrophotometry and visually. Based on the results obtained, it proved feasible to differentiate 4 groups of calculi differing in their content: cholesterol, metallocholesterol, cholesterolphosphatide, phosphatide-protein.