Prerequisite to an intelligent use of any classification of gliomas is a knowledge of the developmental and pathologic forms of neuroglia and of the behavior of neuroglia under various conditions. The classification suggested by Bailey and Cushing1 is serving the purpose for which it was no doubt meant. It provides an excellent basis for selection and study. It is not necessary to employ all of the terms that these authors originally suggested, as was to be expected. The eight types indicated in the accompanying outline seem to be sufficient, at least for the present.
Some of the terms, namely, neuro-epithelioma, spongioblastoma multiforme, astrocytoma and ependymoma, were recognized as histologic subdivisions of the gliomas before the work of Bailey and Cushing. The additional four—medulloblastoma, astroblastoma, oligodendroglioma and unipolar (or better, polar) spongioblastoma—are subdivisions that were described for the first time under these titles in the classification of these authors.
This