THE therapeutic effect of irradiation in allergic diseases, principally asthma, has been the subject of investigation and discussion since 1906, when Schilling, as reported by MacInnis,1 observed that asthmatic patients were frequently relieved after fluoroscopy. Other reports appeared from time to time, but Maytum2 studied it thoroughly in 1939, reporting some 215 cases treated by irradiation over the mediastinum in whom the effect was found to be only temporary in any case and, in 47 per cent of those observed, a complete failure. In 1945, a study made by Army Air Force Surgeons3 of several thousand children and adults with . . .