It is my purpose in this paper to correlate some of the interesting features of low grade tubotympanic infections of secretory character, and to present a case of the mucous type with interesting observations on the mastoid.
The essential anatomic consideration concerns the make-up of the lining mucous membrane of the tube, tympanum and mastoid cells, and such pathologic alterations as are produced by infections of the nonsuppurative type. The pharyngeal portion of the tube has a large opening and is essentially a diverticulum from the nasopharynx, opening and closing with each act of deglutition. On its cartilaginous and membranous base lies muscle tissue covered with ciliated lining mucous membrane. The mucous membrane contains lymphoid tissue and is subject to the same type of pathologic invasion as the nasopharynx, in which there is an abundance of lymphoid tissue. The tympanic end of the tube is essentially a