The placing of the mastoid operation by Schwartze on a rational anatomic basis awakened a tremendous interest in the study of the development of the mastoid. The first studies consisted chiefly of descriptions of the structure of the mastoid.
The next advance in the knowledge of this structure came with an inquiry into the development of the air spaces. The fundamental basis for the present knowledge of the pneumatization of the mastoid must be credited to Wittmaack. His work has been augmented by the more recent researches of Albrecht and Schwarz. I shall not go into the detailed description of the successive stages of development of the tympanum, attic, antrum and mastoid cells. Stated simply, according to Wittmaack's1 theory, the pneumatization of the temporal bone is the result of a transformation due to the successive displacement of the myxomatous embryonic tissue in the preformed cavities by the epithelium. The