“Biologic reactions from X-rays take two forms. The first is a skin lesion known as radio-dermatitis, caused by the skin’s absorbing a large quantity of radiations. The second results from the improvements in X-ray tubes and the use of filters absorbing the radiations of long wave length, currently named ‘soft radiation.’ This reaction takes place deep beneath the skin upon the active cells that are the most vulnerable. It is principally the internal secretion glands that are affected. Among those who continually receive even weak doses, a gradual lessening of vitality takes place, leading slowly to a physiological impoverishment that inevitably carries them off sooner or later.” Dr. Contremoulins was able to escape serious injury up to the outbreak of the World War, but is now a victim of his services to wounded soldiers. As a result of his efforts—and due also, partly, to suits brought against a Paris physician by neighbors who alleged that their health had been impaired, resulting (perhaps) in two cases of cancer—a thorough-going investigation was undertaken by the French Ministry of Hygiene. Dr. Declere of the Academy of Medicine presided over a committee which included Mme. Curie, M. Becquerel, a radiologist; Dr. Vaillant and a number of specialists. A leading member of the Academy said he did not believe that X-rays menaced persons who did not come into direct contact with them. “I intend to study the question by three methods,” he said. “First, we shall make a purely physical examination, studying the action of the rays and in what measure they exert themselves at certain distances. Second, we shall experiment with the living tissues of rabbits, trying various distances several hours a day and noting the effect on the red and white corpuscles and glands of the animals. Then, since it is impossible to make such experiments on human bodies, we shall collect data based on 25 years’ experience with X-rays to see whether physicians in close contact have been burned.” While X-ray treatment cannot be said to _cure_ a deep-seated cancer, it is undoubtedly being given with highly beneficial results in many cases, alleviating much suffering and retarding the growth of malignant tissues. As is well known, tuberculosis can advance to a dangerous stage before it exhibits physical symptoms recognizable by physicians. The X-ray not only brings to light incipient consumption, but reveals the exact place and extent of the lesion. Any abnormalities of the alimentary tract, also, may readily be brought to view, as well as certain effects produced on certain arteries, due to arterio-sclerosis or to angina pectoris (a very painful form of heart disease).