Operable brain tumors are rare. Only 6 per cent. of all cases are suitable for operation. In a recent compilation by Haas 1 122 were tabulated. Permanent successes after operation are rare, even in the experience of such masters in this special field as Horsley, McEwen, Bergman and Keen. Therefore, every case carried to a successful issue is worthy of record. While I have trephined eight times for a supposed neoplasm, I was but twice rewarded by success. In a third case, a syphilitic thickening of the dura equivalent to a tumor formation was found. As a success from a diagnostic standpoint it is equivalent to a successful trephining for tumor. In each of these cases the tumor was in the psycho-motor area, thus again emphasizing the fact that only when in this limited field can brain tumors be recognized with any degree of certainty. My first case was operated