IN MANY cases of poliomyelitis the lesions are not limited to the spinal cord but extend throughout the nervous system, implicating primarily the brain stem. The lesions within the medulla are often very severe and have been studied and reported by many investigators. Recently we1have reported on the medullary changes in poliomyelitis and have succeeded in correlating pathological changes within certain cell groups with the clinical symptoms manifested by the patient. It was felt that other areas of the brain stem warranted detailed study. The present investigation consists of a serial study of the midbrain in cases of bulbar poliomyelitis. The midbrain has received but scant attention in the various publications on this disease. In a number of cases of bulbar poliomyelitis one can be certain that the midbrain has been involved because of the presence of ocular signs. It is estimated that some ocular symptoms will be