1. Multiple, unsustained fevers (41–42°C.) produced by irradiation in a high frequency electrostatic field (10,000 kilocycles) destroyed T. pallidum in rabbits with active syphilitic lesions as determined by the injection into normal rabbits of extracts prepared from their testes and popliteal lymph nodes.
2. One febrile period of 6 hours at a temperature of 41.5–42°C. was likewise found to be sufficient to destroy T. pallidum.
3. Infection with T. pallidum persisted in a control series of untreated rabbits for as long as 395 days after inoculation, but clinical healing occurred in from 3 to 4 months after injection.
4. The time interval between inoculation and fever treatment, or between the end of the fever treatment and reinoculation, did not affect the results.
5. The fever treatment was effective at any stage of experimental syphilis in rabbits.