“Accordingly, in company with Dr. Sicard of Paris, I began to experiment. We worked with animals until we were convinced of the correctness of our method. When we were sure that it was safe we tried it on human beings. I have used it in more than 5,000 cases in Europe without having a single adverse result. “The lipiodol is injected into the brain cavity or the canal of the spinal cord or the bronchial tubes and then a regular X-ray photograph is made. The oil renders the injected part opaque to X-rays and they show up as sharp black images in the photographs. “The method is of particular value when a patient is suffering from paralysis which has been caused by a pressure of a tumor or growth somewhere along the spinal cord. In this case a drop of the oil is injected into the spinal canal at the base of the brain. In a healthy patient it would immediately travel to the base of the spine. But in the paralyzed patient it only travels as far as the point of compression. The X-ray picture therefore reveals the drop of oil as a black spot. The surgeon then knows the exact spot at which to operate in order to find the growth causing the pressure, which in turn results in paralysis. “In diagnosing the lungs with the use of lipiodol the injection in the bronchial tree enables the X-ray worker to tell at once whether the patient is suffering from diseases of the bronchial tubes themselves, or from diseases of the lung tissue, such as tuberculosis.” It is gratifying to be able to relate that along with the improvements already described, progress has also been made in the preparation of photographic plates required by the radiographer. Until recently no photographic plate had been made which fully met the requirements of X-ray work, and there was little contrast in X-ray photographs. They were all much too sensitive to the longer (visible) wave lengths, and produced blurring effects. Early in 1921 an excellent photographic plate, 25 times more rapid than anything previously known, was invented by Dr. Leonard A. Levey, a prominent member of the Roentgen Society. It makes an X-ray photograph of the vital organs of the living body whose movements have hitherto blurred the images on the ordinary photographic plate. Distinct pictures of the heart, lungs and stomach can now be made. Dr. Levey has made snapshot photographs of the heart, lungs and kidneys. All were taken in a flash with the X-rays on the new plate.