Let us briefly recall the anatomy and function of the Eustachian tube, in so far as it concerns the measures advocated in this paper. The Eustachian tube is the passage between the naso-pharynx and tympanic cavity—in length thirty-three to forty millimeters. From its relatively large pharyngeal mouth it extends twenty-five millimeters with walls formed by an incomplete furrow of fibro-cartilage, consisting of a posterior and anterior plate, the anterior being movable. This portion of the tube where not cartilaginous is membranous, which with its lining mucous membrane has considerable thickness. This cartilaginous portion of the tube unites with the remaining ten to fifteen millimeters of the osseous portion of the tube, forming with it an obtuse somewhat circular angle of 135 degrees. At this angle the lumen of the tube is smallest; that is two to three millimeters.
The walls of the Eustachian tube are lined by glandular mucous membrane,