220 diskasp:s of the air-passages of horses. 
congestion may be partial or general, and present various shades of 
colour, from a pale dingy red to a brown, purple, or modena hue ; 
differing in shade in different situations, and sometimes equal 
throughout. The inflammatory injection of the mucous membrane 
of the bronchia generally takes place more in one part than ano¬ 
ther, and is of more frequent occurrence than general congestion. 
The larynx and trachea may suffer active injection, whilst the bron¬ 
chial surfaces are pale and free; and even it is possible to be con¬ 
fined to one side of the tube, if one lung only is affected, corre¬ 
sponding with that of the diseased lung. The inflammatory action 
may be limited to the surface of the large bronchi; whilst above 
and below, or anterior and posterior to this seat, the membrane is 
free from injection. It may exist in the lesser bronchi, producing 
difficult respiration and increase of pulse, with trifling or probably 
no cough; and although it is frequently coexistent with disease of 
the substance of the lungs, still it does not necessarily depend upon 
it; as the whole of the mucous surface, from the glottis to the ter¬ 
mination of the bronchi, is occasionally free from congestion in acute 
cases, and oftener in chronic cases of pneumonia. Tubercles may 
exist in the lungs, and, previous to softening, no inflammatory in¬ 
jection is observable in the bronchial surfaces; but if suppuration 
has taken place in the tubercles, the immediate or adjoining bronchi 
are most commonly inflamed. 
•/ 
Bronchitis may supervene upon tubercular excavation of the lung, 
and proceed throughout the trachea to the larynx, commencing in 
the small subdivisions of the bronchi, and advancing forward to the 
glottis. In diseases of the nasal membrane, fauces, &c. and in 
which inflammatory action more commonly originates, the injection 
extends from these parts to the laryngeal, tracheal, and bronchial 
membrane in succession, and, ultimately, the air-cells and substance 
of the lungs. This mode of origin and extension of the inflamma¬ 
tory action is the most common, but does not usually arrive at the 
lesser bronchia and parenchyma of the lung. 
Thickening of the mucous membrane is a lesion frequently aris¬ 
ing either from injection or congestion, and it is subject to hyper¬ 
trophy from increased nutrition : this latter state of thickening may 
occur in the larynx, or be confined to the epiglottis and entrance of 
the glottis, a very common seat of it in chronic cough. I am aware 
of no particular inconvenience that would arise from this condition 
of the membrane in the trachea; but within the lesser divisions of 
the bronchi it would change the sound of the pulmonary dilatation. 
Hypertrophy may be limited to a particular point of the membrane, 
constituting a tumour upon its internal surface: if in the glottis, upon 
its rima, epiglottis, vocal chords, or ventricles, it would be productive 
