This affection has especially attracted the attention of pathologists when it has been situated in the larynx, where it has received the name of oedema glottidis. It is in this position that its attacks are most intense, and that its consequences are the most dangerous. In some few cases it extends to the mucous membrane of the posterior walls of the trachea and pharynx.

In the cases strictly falling under this head, it occurs as an infiltration of the submucous areolar tissue and of the mucous membrane itself, with a colorless or pale-yellow serum. When it occurs as oedema glottidis it is situated in the mucous membrane of the epiglottis, the dupli-caturae aryepiglotticae, and the mucous membrane of the vocal chords and ventricles; and it constitutes a transparent pale-yellow, fluctuating tumor, which, in proportion to its size and extent, diminishes the aperture of the glottis, and may even entirely close it.

(Edema of the glottis, either in an acute or chronic form, may accompany not only all the inflammatory processes of the laryngeal mucous membrane of which we have spoken, but many other morbid conditions of the larynx and adjacent parts connected either essentially or incidentally with an irritation of the aforesaid mucous membrane. It oc-companies catarrhal inflammations, especially those of an exudative nature, exanthematous processes, typhous and all ulcerous processes on the laryngeal mucous membrane, inflammations of the submucous tissue, tuberculous or cancerous affections of the larynx, etc.

These cases are of the highest importance, for the affection may become rapidly developed, and may cause death by asphyxia, in any of the above-named affections of the laryngeal or adjacent mucous membrane, as that of the velum palati or tonsils, even when the primary disease seems trifling; and it unfortunately happens that we are entirely ignorant of the peculiar conditions under which it is produced in these cases. Sero-purulent infiltration of the submucous areolar tissue may be confounded with true oedema; the former is, however, invariably the result of an intense inflammatory process.