Dr. Frederick Henry Baetjer of Johns Hopkins Hospital has only two of his ten fingers left. He lost the other eight as the result of burns received in X-ray experimentation. Dr. Francis Carter Wood, X-Ray and radium expert of the Crocker Special Fund Cancer Laboratory of New York, calls particular attention to the fact that “the deaths which are occurring now are the results of repeated exposures ten or more years ago, when no one knew what the effect of the rays might be. The burns suffered then were the result of continuous exposure without protection against the rays. One exposure, or a moderate number of them, would do no harm; but before the present perfection of the apparatus it was necessary to adjust the focus for each picture, and the operator would do this by looking at his bare hands through the fluoroscope. This resulted in chronic burns, and the burned flesh formed a fertile soil for cancer. Lead one-quarter of an inch thick will stop both radium and X-rays.” In Dr. Wood’s opinion, workers in X-rays today “need not suffer any ill effects except through their own carelessness.” A discovery which promises to put an end to the dangers to life and limb risked by those who engage in working with X-rays was communicated to the Academy of Sciences of Paris as early as May, 1920. It is the result of experiments by Dr. Pesch of the Faculty of Montpelier, who himself is one of the sufferers from X-rays, and who has long been seeking the means of protecting his young confrères. He found that deep red rays are antagonistic to the ultra-violet rays which produce irritation and burning of the skin, and certain oxidations. Thus, by the simultaneous application of both rays he secures immunity for X-ray workers. He has already proved that erythema can be prevented by the application of red rays. Daniel Berthelot, who announced the discovery to the Academy, recalled that as long ago as 1872 the antagonism of extreme rays of the spectrum had been foreseen by Becquerel in his study of phosphorescence. Dr. Pesch employs a filter composed of a plastic material that allows only the red and yellow rays to pass. It is claimed that by means of this filter not only are the X-rays made harmless, but its employment effects a cure for radio-dermatitis, the affection which has maimed or killed so many of the early workers in X-ray therapy. According to Dr. G. Contremoulins, Chief of the principal laboratory of the Paris hospitals, whose researches and experiments were begun in February, 1896, the usual methods of protection even today are not always adequate. Says he (in _La Démocratie Nouvelle_, Paris, April, 1921): “Young radiologists, especially those born of the war, take no heed of the experience acquired by their elders, being quite convinced that the glasses, gloves and aprons containing lead offer a perfect protection—they even imagine that strictly speaking they might get along without them.