Tumors of the central nervous system having their origin from ependymal cells have long been looked on as a rarity. The reports of workers in the various clinics, particularly of those interested in tumors of the brain, reveal but a relatively small number of ependymal gliomas found in the encephalon. In 1926 Bailey and Cushing1 reported 7 ependymomas among 254 classified gliomas. In a later study Bailey2 found 16 ependymal tumors during an analysis of 566 gliomas. Fincher and Coon3 in 1929 reviewed 8 cases found among 140 cases of glioma at the Sachs clinic. The ependymomas, therefore, would seem to comprise but a small percentage of the glioma family as found in the brain.
The careful investigations of Kernohan, Woltman and Adson4 have revealed a different situation with regard to the number of ependymal tumors found as intramedullary tumors of the spinal cord. In an