IT is not uncommon to see a brilliant local response to radium therapy of primary carcinomatous lesions of the female external genito-urinary organs. This observation prompted a review of the total number of these cases seen in the Section on Therapeutic Radiology of The Mayo Clinic. The study includes all patients with the conditions under consideration, who were treated from 1915 to 1929, inclusive, a total of 95. Radium therapy was first employed at The Mayo Clinic for carcinoma of the vulva in 1915. Rentschler, of the Clinic, reported a similar study recently. In his review he included only cases seen on the surgical service between 1907 and 1927. The present report includes 38 cases studied by Rentschler. This number was referred to the Section on Therapeutic Radiology from the surgical service. The incidence of carcinoma involving the external female genitalia has been recorded by various authors. Schwarz gave the incidence as 1.38; Virchow reported 1.35 or 1.40; Gurlt gave the incidence of 1.48; Taussig gave 1.20. Brady, reporting statistics from Johns Hopkins Hospital, recorded 19 cases of epithelioma of the vulva and 756 cases of carcinoma of the cervix, or a ratio of 1.397. In two of the cases the growth was of the urethra. In The Mayo Clinic the ratio based on histologic study was 1.25. Clark and Norris reported that among 1,119 specimens of newgrowths in the Gynecologic Laboratory of the University of Pennsylvania there were 30 carcinomas of the vulva. There was a total of 1,049 carcinomas in the same laboratory; that is, carcinoma of the vulva represented 2.9 per cent of all gynecologic carcinomas there. Ewing stated that carcinomas of the vulva are not rare; they form 10 per cent, according to Gurlt, 0 f all carcinomas in women. The age incidence in the group on which this paper is based is almost identical to that reported by Rentschler (Table I). Sixty-six patients, or nearly 70 per cent, were between the ages of forty-five and sixty-nine years, the average age being 57.24 years. The youngest patient was thirty years of age and the oldest eighty-five years. The civil state is recorded in Table II. The average number of pregnancies was four. The number of multiparæ in this group was 17, or 19.10 per cent; the corresponding values given by Taussig and by Giesecke were 18 per cent and 43 per cent, respectively. Berkeley and Bonney, in a similar study, reported that 58.6 per cent were married; 25.8 per cent were widows, and 15.6 per cent were single women. Sterility occurred in 48.2 per cent of their cases, and the average number of pregnancies was seven. The frequency with which various parts of the vulva are involved was found by Rothchild, who studied 395 carcinomas of the vulva, to be as follows: clitoris, 62; clitoris and labia of one side, 41; clitoris and labia of both sides, 21; labia majora, 105; labia minora, 35; labia majora and minora, 29; tissue about the urethra, 6; posterior commissure, 11, and Bartholin's gland, 17.