Abstract
The routine histologic examination of temporal bones has served to determine important fundamental facts regarding the intracranial extensions of otitic suppuration. The most important fact to be established has been that in the majority of cases fatal meningitis from acute suppuration of the middle ear has resulted from deep-seated foci of suppuration in the pyramid. These foci have in most cases not been reached by the exenteration of the mastoid cells, while in some cases, because of deep location and atypical symptoms, the otogenic origin of the meningitis has been completely overlooked until proved by the histologic examination. Next in importance is the established fact that foci of suppuration in the petrous pyramid have occurred almost always in cases in which pneumatization of the pyramid was present. Exclusive of diffuse suppurative labyrinthitis and hematogenous metastatic foci in bone marrow, the occurrence of foci of suppuration has been found to depend