I SUPPOSE the cholecystogram is generally accepted among the most useful and accurate of all radiological examinations that we perform. The reputation of this diagnostic procedure rapidly became established after its introduction by Graham and Cole over 40 years ago, and careful refinements in technique have gradually increased the accuracy of the method until one can confidently say, at the present time, that oral cholecystography results in an accurate diagnosis in 95% of cases or better. The error in the very small group that remains usually relates to nonvisualization of the gallbladder for some extraneous cause other than actual gallbladder disease. Recently, our attention, however, has been attracted to the occasional case of proven gallbladder disease occurring in patients who have had apparently normal cholecystograms, even upon repeated examination. Report of Cases Case 1. —A 42-year-old white woman was admitted to the hospital on May 7, 1964, and discharged on