PRIZE ESSAY 
349 
cho-vascular systems. These systems will be spoken of together 
as they are so intimately connected, the bronchus lying between 
the artery and vein, all being surrounded by a sheath of connec¬ 
tive tissue, in which ramify the lymphatic vessels. 
On cutting across a portion of diseased lung, we find the bron¬ 
chus occupied with a dense mass of granular material, which com¬ 
pletely occludes the smaller bronchi and tapers off into the larger 
ones. If this is removed, we find the mucous membrane rough, 
discolored (dull grey or yellow), and stripped of its epithelial 
lining. 
The walls of those air tubes which contain the firm plugs are 
always enormously thick and dense. And, besides this thicken¬ 
ing of the walls of the bronchi, their delicate connective tissue 
sheath is the seat of dense exudation ; as a consequence, becoming 
a tough and rigid case. This exudation appears to be, in charac¬ 
ter, similar to that which fills the interlobular spaces. 
As the blood-vessels ramify with the bronchi—surrounded by 
the same connective tissue sheath—it is not surprising that we 
cannot have morbid changes in the bronchial without speedily 
finding them in the vascular system. 
As a matter of fact, the walls of the blood-vessels soon be¬ 
come engorged, the external coat being first attacked, the others, 
in turn, becoming thickened and rigid. Red spots are seen here 
and there on the inner coat. It may be destroyed entirely for a 
considerable portion, and then a clot gradually forms which may 
completely fill the vessel. At once the stoppage is complete, the 
clot seems rapidly to grow into the larger branches, at last pro¬ 
ducing complete occlusion of the larger trunks. 
The foregoing account of the Pathological Anatomy is much 
condensed from Professor Gerald Yeo’s report on the subject. 
The question of where the disease commences is one which has 
been considerably discussed, but which is not at present of any great 
practical importance. Prof. Yeo holds that it always commences 
in the “ air passages as a chronic inflammation associated with 
destruction of the bronchial mucous membrane,” while the con¬ 
trary opinion is that it may originate anywhere, either as above 
or in the lung tissue or the pleura. 
