In many cases of traumatic epilepsy the presence and location of a scar in the brain may be demonstrated by fractures of the cranial vault, by neurologic defects or by the pattern of the epileptic seizures. Encephalograms frequently offer contributory evidence of the position of a scar and sometimes, when other signs are absent, may be the only clue to its location. Recently electroencephalograms have been shown to be of value for this purpose. Too frequently, however, surgical intervention in cases of traumatic epilepsy must be withheld because the presence and location of a circumscribed scar in the brain or meninges cannot be demonstrated at all or the evidence is insufficient or conflicting. In cases of this type, in which the importance of the trauma preceding the occurrence of epileptic fits may also be doubtful, pneumographic examination of the subdural space may be of value. Some years ago Penfield and