As a result of the rather intensive study of syphilis during the past few years, experimental methods of investigation of this disease have been evolved and our fund of information has been increased thereby. It is believed that the results to be obtained from a study of experimental syphilis will be far greater if the human factor is brought into the equation. We cannot very well draw comparative conclusions as to the behavior of nervous syphilis in the rabbit, unless we know that the strain in question does and has produced nervous involvement in the human being. The end for which we have worked is the determination in the rabbit of the various characteristics and peculiarities of the initial lesion and subsequent course of the disease, with strains of syphilis known to have produced nervous syphilis in the human being, compared with other strains known to run a mild course