Irradiation treatment of chronic myelogenous leukemia was first undertaken by Senn1in 1903, using long wave length roentgen rays. It was not until after Rénon, Degrais and Desbouis,2in 1913, and Ordway,3in 1917, reported the effect of radium on the disease that adequate irradiation was given at all frequently so as to produce very often marked alleviation of symptoms. In recent years and with the advent of short wave length roentgen-ray therapy, constantly greater numbers of these patients in an increasing number of localities are receiving intensive irradiation with great benefit. The reports by Ordway,4Peabody,5Giffin,6Vogel,7Wood8and Rosenthal9are among those that indicate the value of this form of treatment. It is recognized that irradiation frequently brings about striking remissions of the disease, so that patients who are often in a distressing and sometimes an apparently serious