CROUP OF THE TRACHEA AND BRONCHI. 87 



the bronchi of the third and fourth order ; and, as this constitutes a dis- 

 tinct disease, it must be spoken of separately. 



This primary croupous bronchitis attacks by preference persons 

 during the age of adolescence, but we have not as yet any accurate 

 knowledge as to either its predisposing or exciting causes. 



ANATOMICAL APPEARANCES. The tree-like ramified tubes, already 

 described, are formed by the extension of the croupous process from 

 the larynx into the trachea and commencements of the bronchi. The 

 croupous plugs which fill up the bronchioles in pneumonia we shall find 

 to be a constant feature in the sputa of pneumonic patients. 



In primary independent croupous bronchitis the same condition of 

 the bronchial mucous membrane is found, and with the same coagulated 

 exudation upon it which we have described as existing upon the mucous 

 nembrane of the larynx in laryngeal croup. In the greater branches the 

 calibre of the canal is not completely occluded ; the coagula are tubular ; 

 but in the smaller bronchi they form cylindrical plugs. Croupous 

 bronchitis is seldom spread over the whole lung ; generally it is partial, 

 and confined to a small number of bronchi ; but to this rule there are ex- 

 ceptions. I know of a young girl, of fifteen years of age, who for years 

 has almost daily coughed up a complete cast of the left bronchial tree. 



SYMPTOMS AND COURSE. The small extent of bronchial croup, as 

 well as the absence of the fever, causes the progress of this disease to be 

 quite different from that of croupous inflammation in the larynx. In- 

 deed, while the latter is an extremely acute disease, croupous inflamma- 

 tion of the bronchial mucous membrane is, in some cases, a chronic one, 

 which drags on for months, and even years. 



The patients generally suffer from moderate dyspnoea, and nothing 

 save the pale countenance and a certain relaxation and sleepiness indi- 

 cate that respiration is carried on incompletely, and that the blood is 

 not entirely decarbonized. From time to time, convoluted masses are 

 ejected, after painful and spasmodic coughing. These become disen- 

 tangled in water, and then present regularly-formed casts of the bron- 

 chial ramifications, consisting of tree-like, repeatedly-forked coagula, 

 generally covered with a little blood. Upon auscultation, we hear ex- 

 quisite rhonchus sibilans, corresponding to the extent of the bronchial 

 croup ; or, as in my case, the respiratory murmur is wanting as long as 

 the tubes are filled with exudation, and returns as soon as the membrane 

 has been expectorated. From time to time the disease, which, as we 

 have said, is usually chronic in its course, takes on exacerbations. These 

 often commence with a chill, and are followed by fever. The process 

 sometimes spreads throughout other regions; great dyspnoea ensues; 

 breathing may become insufficient, and death may take place under the 

 often-mentioned symptoms of insufficient respiration. 



