Sacoma, autrement dit Fungus, est vne excroissance de chair qui vient de l'aliment propre de la partie où elle naist.—Ambroise Paré. During the course of the last century the diagnosis of sarcoma of the brain was often made, and if the term be understood in its original sense, namely, to designate a soft, fleshlike (σáρξ, flesh), rapidly growing, cellular tumor, this diagnosis was probably correct; but as the use of the term began to be restricted to the rapidly growing tumors of mesodermal origin, it was soon felt that for cellular tumors of the brain it was a misnomer, since they were certainly of neuroglial nature and hence of ectodermal origin. Consequently, they came to be called gliosarcomas, but ere long this term also was superseded by that of glioblastoma or spongioblastoma, and the existence of a true malignant mesodermal tumor of the brain was doubted. Yet at first