During the past few years, interest in the production of fever by physical means has greatly increased. More than 600 articles have been written and published on the subject. Excellent research work has been done, and conservative scientific conclusions have been drawn. The value of fever therapy as an important therapeutic agent in the treatment of certain diseases has been definitely proved. The treatment of more than fifty diseases by means of artificial fever therapy has been attempted. The results in the majority of these diseases were not encouraging, although with a selected few the method has given promise of great usefulness. It must be emphasized, however, that fever therapy is probably of little or no value in the treatment of many diseases concerning which its use has been studied, and in some diseases it may even become dangerous. GENERAL PRINCIPLES Numerous studies on the effects of fever produced by