THE International Radiological Congresses have made it a rule to place on their programs, in addition to the scientific questions, radiological-organization problems of general interest for medicine as a whole. The present Congress has placed on its program for discussion that most central of all radiological-organization problems: the integration of radiology into medicine as a whole. The President of this congress, Dr. Arthur Christie, and Dr. William Mayo, America's world-renowned surgeon, ruler of one of the metropolises in the realm of medicine, have displayed for us their broad view of one side of the problem: the unity of medicine. To me has been given the honorable task of opening the discussion of the problem's other side: the role of radiology as a member of the unity of medicine. For the one who can remember the birth of radiology, the story of the development of this science is a marvelous one. The new light became visible like a dazzling meteor in the evening of the nineteenth century. It surrounded the morning of our own century with the rosy light of hope and promise. Like a glittering sun it shines resplendent on the working day of the twentieth century, revealing new fairways and fresh horizons in nearly every land in the world of science. In medicine, radiology has played the role of a pioneer and a creator in the spheres of diagnostics and of therapy. Its revolutionizing work in the domain of diagnostics is that it has extended. the physician's field of vision to include the interior of the living man. Roentgen diagnostic methods have increased diagnostic skill in almost every branch of the medical science, and in this way have contributed in a high degree to the reliability of our judgment of the indications of treatment and have thereby improved the results of treatment. I will merely remind my hearers that roentgen diagnostics have contributed most essentially to the magnificent progress made during the present century in the provinces of abdominal, thoracic, and cerebral surgery, and in orthopedics. As regards internal medicine, too, roentgen diagnostics have become an indispensable guiding star. Also radiotherapy, that is, Finsen-, Roentgen-, and Curie-therapy, has created an epoch in the history of medicine. By its destructive action on malignant tumors and dermatic fungi, by its power of hastening or causing a healing process in inflammatory conditions of various kinds, and by its readjustive action on certain disturbances in the functions of the endocrine glands and the hematopoietic organs, radiotherapy has become an indispensable weapon in the service of medicine. But how is it that radiology has come to play such a röle that one is entitled to say it has set its seal most decisively on the medical science of the present century? And how, in the future, will radiology be able to continue to play this important part?