The dietary factors, as a cause on increasing incidence of gallstones in Japan, were studied. The increase in the incidence of gallstones at autopsy was nearly paralleled with that of fat intake on a line graph and reversely the carbohydrate intake including crude fiber showed a decreasing trend. In the nutritional survey of patients with gallstone, the fat intake was 22% higher than that of the control group, and the crude fiber intake was 18%lower. Comparing the incidence of cholesterol stones during each 10 years of 1953-1962 and 1969-1980 with the nutritional intake, the incidence of gallstones increased by 25% and the fat intake by 120%, but the carbohydrate intake including crude fiber decreased by 14%. Fromthe above, it was considered that the increase of the incidence of cholesterol gallstones was related to the increase of the fat intake and the decrease of the crude fiber intake. A study on black stone was carried out with an infrared spectroscopic analysis and scanning electron microscopic observation, and wenowproposed a new classification of this type of stones.

Several kinds of recently advanced microanalytical techniques—like electron probe x-ray microanalysis, laser Raman microprobe, and Fourier transform-infrared spectroscopy combined with a microsampling method—have been used for the study of the microstructure of gallstones. The organic and inorganic constituents of three kinds of gallstones are characterized on a microscopic scale. The microstructure of a cholesterol-bilirubin gallstone with a layered structure has been studied with particular emphasis. Small white particles contained in both a bilirubin gallstone and a cholesterol-bilirubin mixed gallstone have been found to consist of calcium salt of a fatty acid, probably calcium palmitate. The results obtained here will be very useful for understanding the mechanism of the gallstone-formation process.

A very convenient classification of the causes of cholelithiasis is that of Gumprecht (Deutsch. Med. Woch., 1895, 224). He divides them into : first, physical, such as age and sex; second, as sequel\l=oe\ of other diseases; third, chemic alterations in the com-