The introduction of radium into general therapeutic use has been accomplished by much discussion and also considerable unjustifiable criticism. In the light of past achievements, however, we are in duty bound to review our work with radium and continue in its scientific application, secure in the knowledge that in certain phases of cancer it has demonstrated therapeutic results as yet unequalled by any other medical or surgical measure known. Outside of the comparatively few institutions where radium is supplied in the form of emanation, the bulk of independent radium therapy is carried on by means of elemental radium in the various glass and metallic containers with which we are all acquainted. With the advent of the aerial mail service, even the remotely located radiologist can have placed at his disposal, upon telegraphic request, a suitable quantity of radon or radium emanation of exact measurement and known content. This service is invaluable to those who have not the facilities of an emanation apparatus. According to the experience of the writer, the field where the best results have been obtained from radon implants or seeds is the oral cavity, particularly the tongue. In no other location has this form of therapy seemed to us so surely the best, unless it be in such nodules or tumor masses of the rectum, vagina or cervix uteri as will not react so as to injure seriously a functionating mucous membrane. In early cancerous lesions of the tongue, our experience with radon seeds has been gratifying. In the bladder, prostate and rectum, we have not been so fortunate. In the majority of malignancies, we have noted that outside of a very few favorable cases where a metallic needle imbedded for a limited time gave the desired result, we accomplish a great deal more with much less pain and discomfort to the patient by the screened applicator method. Similarly, our use of the metallic needles imbedded in tongue or throat lesions have given way, either to the radon seeds or to screened topical application. In tissues which are hyperplastic and free from adjacent sensitive structures, as, for example, polypi or small fibroids of the cervix uteri, judicious employment of metallic needles will yield more satisfactory end-results than any other method of eradication. On the other hand, in cancerous nodules elsewhere located, the response with needles has not measured up to what should theoretically be expected from such treatment. Many of us at one time advocated the use of needles imbedded in the various cancer nodules of the breast. We have, in our Clinic, discontinued this procedure for several reasons, the chief one being the severe reaction and sloughing, with a long, tedious healing period which sorely tries the patience of both the operator and his charge. When we have reverted to the older technic of screened external applications, we have secured equally good end-results with no such serious sequelæ.