IT is now the consensus of opinion among radiotherapists that lymphoid tumors offer the conditions best adapted to treatment by radium or its emanation. Lymphosarcoma, however, though peculiarly susceptible to exposure to radium, is of such a malignant character, and so prone to metastasis, that few “cures” by the use of radium have ever been reported. Yet, as surgery, under these conditions, is even less effectual, radium still offers the greatest hope of amelioration, for, as it has been aptly phrased, the effect of radium is to strengthen Nature's barrier of lymphocytic infiltration, instead of sweeping it away by excision. Under radium therapy many of these sarcomatous growths have shown marked regression, and in certain cases, where the growth was still in its early stage when it first came under treatment, being still completely localized, the disease has apparently disappeared permanently. Though these instances are lamentably few, one has but to consider the practically universal recurrence of sarcoma after surgical extirpation, to realize that radium is offering a more cheerful prognosis than has ever before been held out to the unfortunates who become victims of this highly fatal malady. Sarcomata belonging to other groups, such as neuro- or osteosarcoma, have, however, proved uniformly resistent to any form of radiation. Embryonal tumors of the testicle, which are highly malignant and peculiarly likely to metastasize, have been demonstrated to be exceedingly susceptible to radium, but, as with sarcomata, their tendency toward early metastasis makes any form of treatment of little avail unless the patient comes under the care of the radiologist very soon after the malignant process is initiated. Metastasis by the way of the venous system quickly gives rise to secondary tumors in widely separated parts of the body, such as the lungs, liver, kidney, stomach, or even the brain, and these very often so quickly attain large dimensions as to attract more attention than the original growth in the testicle. Many factors operate to make the diagnosis of these testicular growths obscure. They are often confused with syphilitic lesions, and frequently so much time is lost in the unavailing administration of anti-luetic treatment, that when the patient is finally placed in the hands of the radiologist, he is beyond the help of radium or any other therapy. Yet, in those cases where treatment has been promptly instituted, the combination of surgery and radium exposure has given most encouraging results. Radium emanation enclosed in a 2 mm. lead filter has been successfully applied preliminary to operation, the usual dosage being twelve thousand millicurie hours at a 6 cm. distance. This same dosage is applied directly over the testicle as well as along the spermatic cord.