This contribution is an analysis of the histologic features of various types of focal non-neoplastic lesions of the brain. The 95 specimens studied were excised at operation in an attempt to cure patients of habitual epileptic seizures. In each case the evidence indicated that the tissue excised was the starting point for the neuronal discharge which produced focal seizures in the patient in question. These lesions have resulted from traumatic injury, healed abscess of the brain, arterial occlusion and focal ischemia. The features which are common to all these different lesions must be important in the etiology of epilepsy.
The meningocerebral cicatrix which produces chronic epilepsy was studied in a series of post-traumatic cases by Foerster and Penfield.1 They concluded that laceration of the brain results in downward growth of connective tissue from the dura with a rich plexus of vessels which intermingles with astrocytes, the fibers