In the experiments described in this paper, neurosyphilis was treated by artificial fever, the body temperature having been raised my means of short-wave diathermy, and body-heat irradiation prevented by use of an air-conditioned cabinet. The A. considers the optimum rectal temperature to that between 39,5°C (103°F) and a little above 41.C (105,8°F); however, temperatures above 38°C (100.5°F) were accepted as beneficial. The treatments lasted an average of 8 hours, in a total average number of 10. The process was aplied to 15 patients, 11 suffering from general paresis, 3 from cerebral syphilis and 1 case of tabes. Among the cases ofe general paresis there were 5 of the expansive and 4 of the demented type, one of which in the terminal period; 1 patient had a striatal syndrome of syphilitic origin and the vascular inflammation due to syphilis. The results were as follows: 7 complete clinical cures, 3 partial improvements, one case not influenced by treatment. In percentages this would mean 63.64% clinical-cures, 27.27% partial cures, 9.% unchanged by treatment; no deaths. Of the 3 patients with brain syphilis, 2 were considered clinical cures and 1 was improved. The patient with tabes obtained notable relief from pain. The A. compares these results with those obtained by means of malaria-induced fever in 26 cases of general paresis and 3 cases of brain syphilis. Results obtained in the latter case were the following, for general paresis: clinical cures, 6 (23%); partial cures, 11 (24%); patients not improved, 3 (12%); 1 death; 1 case of post-malarial psychosis. Four of the patients presented no clinical symptoms, but only a positive reaction to the usual tests for syphilis in the spinal fluid. Of the 3 cases of brain syphilis treated with malaria, 1 was a clinical cure and 2 improved. The A. summarizes their findings, from the clinical standpoint, as follows: Electrical fever is not only less harmful, but it offers a greater percentage of cures, as compared with malariotherapy. Because of its relative harmlessness, it may be used in cases where malariotherapy is out of the question. Its use should be considered mandatory with malaria-resistant individuals, whether because they have previously had the disease or becuse of a constitutional resistance to temperature rises after malarial inoculation, as frequently occurs with negroes or mestizos. The A. convinced also that shor-wave diathermy should be used in those cases where malariotherapy has been used without results or with scant improvement, since, because it offers a high degree of control over the temperature, it permits operators to achieve a high degree of fever for the time desired - factores not obtainable in malaria, where there is virtually no control over the fever process. A significant fact observed by the AA. is that the artificial fever process was better tolerated by the patients, and in no case were there any unfavorable effects on the general state of health, as so frequently happens with the malarial method. In spite of the foregoing conclusions, the A. still considers eletropyrexy to be in the experimental etage, since there is still a number of details to be studied, not only as to whether classical or short-wave diathermy is to be preferred, but as to the establishment of an optimum technique, based on experimental results. Thus, while some operators prefer long sessions, once or twice a week, others counsel shorter and more frequent treatments; some prefer shorter sessions with the use of high temperatures, while others believe in lower temperatures for a longer period of time. The fact is that we still do not know whether the therapeutic effect is principally dependent on the height of temperature, the time of application, or both. Another point which arouses controversy and awaits further data has to do with the mechanism of the therapeutic action itself of artificial electric fever. If it is finally ascertained that short ware diathermy is of equal or superior efficiency to malariotherapy, there will be no further defense for the theory of the specific action of the Plasmodium; if this is true, as it would seem to be, we shall have to believe that therapeutic results depend on the fever factor alone. This being postulated, the best pyretotherapeutic process will be recognized as the one which allows the operator to obtain an optimum temperature, maintain it for an optimum length of time, with the least danger towards the patient - and this process is electropyrexy.