The seven reports given in this paper serve to illustrate the various clinical manifestations of lymphoblastomatous involvement of the nervous system. In three of the cases the lesions were predominantly cerebral; in one, cerebellar and in another, meningeal; in the other two, the cranial nerves and the spinal cord were most disturbed. The cases, therefore, will be classified under these gross headings as a matter of convenience. Practically all of the so-called "cerebral cases," however, showed evidence of involvement of the cranial nerves at one time or another, and at least one showed evidence of cerebellar disease. The term "lymphoblastoma" requires a word of explanation. It was suggested by Mallory to describe those tumors the cell type of which is the lymphoblast, the precursor of the adult lymphocyte. Owing to the confusion of terminology in the literature, in which one finds lymphogranuloma, lymphosarcoma, Hodgkin's lymphogranuloma and pseudoleukemia used indiscriminately, the