This is very frequent in certain portions of the air-tubes; it is often remarkable for its great intensity, and is of the highest importance from its sequelae. These observations especially apply to chronic bronchial catarrh, but the affection is also common in the larynx and trachea, and sometimes extends over the whole course of the air-tubes; it is generally, however, then especially developed in some one particular part. It possesses the usual anatomical characters of chronic inflammation of mucous membranes; but as no acute catarrh is so liable to frequent relapses, and exhibits such a tendency to become habitual as that affecting the air-passages, so also the chronic form is here especially liable either to relapse into acute inflammation, with an augmentation of intensity, or, on the other hand, to degenerate into blennorrhoea. It gives rise to swelling of the mucous membrane, especially on those parts of the larynx which we have already described as abounding in glands, thus causing glandular hypertrophy', mucous polypi, and cauliflower epithelial growths; similarly in the trachea, and more especially in the bronchi, it causes a spongy thickening of the mucous membrane; and these affections may lead to hypertrophy and relaxation of the submucous muscular strata, of the fibrous portions of the vocal apparatus, and of the fibrous sheaths of the bronchi, and sometimes to ulcerous destruction, especially of the larynx, in the form of diffuse catarrhal suppuration, or of catarrhal follicular ulceration.

Chronic catarrh may further give rise to diminution of the calibre of the air-passages, amounting even to their perfect closure; the previous loss of substance sometimes inducing adhesion and perfect obliteration of the bronchial tubes. At other times, associated with hypertrophy and paralysis of the tissues, it gives rise to bronchial dilatation.

The quantity of whitish, cream-like, or yellow purulent secretion that is thrown off by the bronchial mucous membrane in a state of blennor-rhoea, is very remarkable, especially where dilatation is at the same time present. The cases of what is termed Phthisis pituitosa (asthma humi-dum, bronchial blennorrhcea), fall under this head; and on making an incision through the lungs, abundance of mucus is seen gushing out of the divided bronchi, and pouring over the cut surface.

Both the acute and the chronic form of pulmonary catarrh, may occur as isolated and substantive diseases; they are, however, frequently associated with catarrhs of other mucous membranes. The acute is frequently of an exanthematous nature, and seems especially connected with measles, small-pox, and typhus; while the chronic form is often of a gouty, scrofulous, or syphilitic nature, and is associated with the most different pseudo-plastic processes on the mucous membrane, and in the submucous tissues. It is the chronic form of bronchial catarrh which accompanies pulmonary tuberculosis, especially true tuberculous phthisis. Moreover, it very frequently arises from mechanical hyperemia induced by cardiac diseases.

Gonorrhoeal catarrh of the larynx requires especial notice, in consequence of its sequelae. In the form of gonorrhoeal metastasis, it attacks the mucous membrane of the epiglottis, and the lateral duplicatures of the glottis and of the superior vocal chords, converting the mucous membrane and subjacent areolar tissue into a fibro-lardaceous, white, resistant structure of considerable thickness, thus giving rise to contraction of the rima gottidis and the cavity of the larynx. This constitutes gonorrhoeal stenosis of the larynx.

There are two distinct modes in which chronic bronchial catarrh acts injuriously on the parenchyma of the lung. It sometimes causes emphysema; at other times collapse and obliteration of the air-vessels, and consequently obliteration of the pulmonary tissue itself. Amongst its sequelae we may mention livor, cyanosis, active dilatation of the right side of the heart, and hydrothorax; and the patient dies asphyxiated through some of these affections, or sinks from tabes under the form of Phthisis pituitosa.