THE February, 1924, issue of the Journal of the American Medical Association contained an article entitled, “A Preliminary Report on the Roentgenographic Examination of the Gall Bladder; A New Method Utilizing the Intravenous Injection of Tetrabromphenolphthalein Sodium Salt,” by Drs. E. A. Graham, W. H. Cole and G. H. Copher of St. Louis. While investigating tests to ascertain the function of the liver, the discovery was made that when certain drugs were administered intravenously the bile became opaque to the X-ray, causing the outline of the gall bladder to be clearly defined. Different dyes were used experimentally, the outcome being that the tetrabromphenolphthalein sodium salt was found to be the most practical for routine use. This discovery was received with enthusiasm by all the roentgenologists throughout the world. Up to this time the roentgen diagnosis of gall-bladder lesions had not been satisfactory. In a fair percentage of cases, if special attention were paid to technic, gallstones, pathological gall bladders and adhesions were recognized, but a considerable proportion remained that could not be detected. With this new method we are now able to not only discover the pathology present, but, in addition, to give some definite data as to the size, shape, location and emptying power of the gall bladder, and of no small importance is the ability to study the function of the liver, recognizing delay. The greatest achievement is the fact that gallstones which are non-opaque to the X-ray, when surrounded by this opaque bile are outlined by negative shadows which can be readily recognized. In some cases the surface of the non-opaque stones absorbs a sufficient amount of the dye-impregnated bile to become visible in the roentgenograms. It was early recognized that if, with no fault in the technic, the gall-bladder shadow did not appear at any time during the frequent necessary X-ray examinations after the injection, that fact was due to one of the following reasons: A. In Cases without Obstructive Jaundice 1. Obstruction of the cystic duct due either to stone or stricture. This includes cases of hydrops or empyema of the gall bladder. 2. Obliteration of the lumen of the gall bladder due to shrinkage or tumor growth or packing with calculi. 3. Thickening of the walls of the gall bladder with insufficient lumen and bile content to cast a shadow. 4. Unusual thickening of the contents of the gall bladder (bile mud) so that it cannot mix with the recently excreted bile from the liver containing the test medium. 5. Defective liver function, with imperfect excretion of the opaque bile. Theoretically in all other cases without obstructive jaundice the gall bladder should be visualized. B. In Cases with Obstructive Jaundice 1. Shrunken, contracted and empty gall bladder found, according to Courvoisier's law, in the chronic intermittent form of obstruction produced by a calculus in the common bile duct.