ON May 8, 1919, I presented a paper2 upon this subject before the Philadelphia Roentgen Society, but I had been using this method in my roentgen examinations for ten years previously, and had frequently referred to the method at medical meetings during this time. I am showing you some slides which were made in 1911. It seemed such a rational procedure that I presumed that it was used rather generally. I do not find the method recommended, however, in the leading text-books, and it is surely not in general use. I am convinced of its great value, and therefore I take this opportunity of bringing it to your attention. I have studied about a hundred cases, and in only a few of these was a pneumo-roentgenogram requested,—I think chiefly because the method is not generally known. In nearly all of these cases the patient was sent for an X-ray examination of the kidneys, ureters or bladder for urinary calculus, and when I suspected a carcinoma, or when such a diagnosis had been made, I made a pneumo-roentgenogram...