The morphology and still more the etiology of tumors is as yet an unfinished chapter. Fifty years have elapsed since R. Virchow (18631865) published his epochmaking work Die Krankhaften Geschwülste and thereby founded the morphology of most of the now well-known species of tumors.
Since then a number of prominent scientists have used the time well. I will mention only Ribbert and his numerous contributions to the subject of tumors. But still new forms are discovered or formerly not well understood forms are reclassified. Such is the case with regard to the group of neoplasms this paper is to discuss—certain tumors of the nervous system and of the adrenal glands. These peculiar growths have formerly been classified as sarcoma, the storeroom containing so many incongruous matters which need a thorough putting to right. This process is, however, progressing, as pathologic new formations which prove to be