Abstract
Some new methods have been developed using an electron microprobe analyser to study gallstones. These methods have been used to show the distribution of major and trace elements, and to investigate the chemical bonding of sulphur present in small highly pigmented regions, from which chemical information would have been difficult to extract using other methods. Supporting methods of X-ray diffraction and infrared spectroscopy have been used to identify the crystalline and amorphous constituents of the regions of interest located by microprobe analysis. The observed patterns of materials distribution have been interpreted in terms of some possible formative events. Particular significance has been attached to the distribution of iron and other trace metals, and to the precise arrangement of the different layers of calcium salts and cholesterol. It has been inferred from the arrangement of the materials present that the calcium salts and cholesterol may not have precipiated independently during stone formation. Calcium salt precipitation appeared to precede that of cholesterol in all the stones examined, and evidence has been presented to show that the cholesterol may have precipitated as a consequence of damage to the gallbladder wall, caused by the calcium salts.