In an earlier paper we emphasized the need of specific etiologic diagnosis as a prerequisite for the intelligent use of bacteriophages in the treatment of infections. This point of view requires no defense. It is well, however, to recognize that human disease may not infrequently present a problem which defies satisfactory scientific elucidation and that the physician may be required to assume the responsibility for the treatment of a patient whose disorder is only imperfectly understood.
We feel that some apology is required as an introduction to the discussion of the application of bacteriophages in the treatment of the often obscure, nonspecific types of chronic inflammation of the large intestine and of fistulous tracts through which are passing the multitudes of intermingled micro-organisms and heterogeneous remnants of food in the human feces. In some instances it may be possible to recognize among the microbes an individual species of outstanding importance