Three of the six cases recorded in this paper occurred during or after the recent prevalence of influenza, the history of an influenzal attack appearing to precede the occurrence of the involvement of the nervous system. The other three cases were observed at times when epidemic poliomyelitis prevailed. Five of the cases were clearly instances of focal encephalitis. The fifth case was doubtfully one of cerebello-bulbar encephalitis. In several of these cases the differential diagnosis most considered was that of cerebello-pontile tumor and localized encephalitis. A close scrutiny of the general symptoms of the cases, however, indicates that these were rather of an infection or toxi-infection than of a progressively increasing neoplasm. The latter was presumed in several of the cases, for a time at least, because it was held that the symptoms gradually augmented. Strickly speaking, this was not true, although the symptom picture was not completed as