Although much has been written upon porencephaly, yet detailed descriptions of the resulting alterations in the constituent neurons of the cerebro-spinal axis are few in number. As a further contribution in this direction the present case has been studied, and the changes found have been recorded as far as possible graphically. No attempt has been made to collect together the literature, largely clinical, of porencephaly, as it has been felt that this cannot be profitably done until the minute anatomy of the central nervous system has been placed on record in a much larger number of cases than is at present available