ACUTE CATARRHAL BRONCHITIS. 475 



brane of tlie larger tube, as also the trachea and larynx, may 

 show patches of a dark greenish metallic hue, a character 

 which, somewhat modified, we almost invariably meet Avith in 

 those animals which have either, when affected with the disease, 

 been of a special cachectic condition, or, if in vigorous health, 

 have had operating on them serious depressing influences. 



In almost every instance where the amount of bronchial 

 secretion is great and particularly viscid, we will observe more 

 or less consolidation of lung-tissue ; this is generally of a diffuse 

 character, although we occasionally see it also limited to small 

 and circumscribed patches. When occurring extensively this 

 condition is usually associated with acute and rapidly fatal 

 cases. When glanced at hastily, this state of collapse or con- 

 densation of lung-tissue, which arises from plugging more or 

 less perfectly of a bronchus or bronchi leading to the parts, 

 may be passed over or mistaken for consolidation, the result of 

 ordinary pneumonia. It is, however, different from that con- 

 dition both in its general appearance and the manner in which 

 it comports itself when incised or minutely examined. This 

 collapsed lung-tissue is of a dark or dirty violet colour extern- 

 ally ; it feels less crepitant than healthy lung-tissue, but more 

 so than the same when suffering from hepatization. 



When cut into, it is of a mahogany-brown colour, the extent 

 of this depending upon the amount of blood it contains ; the 

 exuded material is a slightly opaque bloody serosity, and may 

 be mingled with pus from the inflamed bronchi. In true pul- 

 monic consolidation the result of inflammation of the paren- 

 chyma of the lungs, where the air-vesicles are obliterated 

 through exudation into their interior, we have on incision, or 

 may obtain by scraping, a thick pasty material, chiefly made 

 up of granular elements and various cell-growths generally 

 found in inflammation of parenchymatous organs. If of any 

 time duration, this collapsed and condensed lung-tissue 

 becomes atrophied, the special pulmonary structure seems to 

 be replaced by fibrous material, the whole condensed portion 

 occupying less space than in health. As an invariable accom- 

 paniment of the atrophied condition of the collapsed and con- 

 densed lung we find vesicular emphysema, this emphysema 

 seeming to compensate for the diminution in bulk sustained 

 by the altered lung-tissue. This emphysematous condition 



