CROUP. 11 



persons who have died with all the symptoms of croup, has given rise 

 to an artificial division into true and false croup, and even to-day there 

 are many physicians who maintain that, in the subjects in which, upon 

 autopsy, no membrane has been found in the larynx, the cause of death 

 has not been true croup. 



In croup, too, a fluid plasma first exudes, and it, of course, does not 

 coagulate until after exudation. If ejected from the body, either in the 

 coagulated or liquid form, on section we find the larynx to be free ; but 

 we have to do with exactly the same disease as that in which a coagu- 

 lated coating is found upon the mucous membrane. Croupous exuda- 

 tion sometimes has the consistence of a thick cream ; sometimes it forms 

 a compact, tough membrane; sometimes it entirely lines the interior 

 surface of the larynx as a continuous sheet, and is prolonged into the 

 trachea and even into the bronchi, forming tubular and ramifying clots ; 

 sometimes it only presents isolated flakes and patches, which cling here 

 and there to the mucous membrane. 



The softer and thinner pseudo-membranes may generally be de- 

 tached from the mucous surface with ease ; the tougher and more co- 

 herent ones cling more firmly. Upon the external surface of this firm, 

 strong substance, which is often more than a line in thickness, we fre- 

 quently may notice numerous red streaks, and points of adherent blood, 

 which correspond to small bleeding spots of the mucous membrane 

 upoi whose areolar layer the exudation is situated. 



After persisting for a longer or shorter time, the pseudo-membranes 

 gradually become loosened by a serous exudation which proceeds from 

 the mucous surface, and are expelled either in the form of continuous 

 tubes and sheets, or in small flakes and patches. 



Under favorable circumstances, the epithelium is soon reproduced, 

 and the laryngeal mucous membrane returns to its normal condition. 

 In other cases, a fresh membrane succeeds upon the fall of the first one, 

 and thus the process may be many times repeated, until the disease ex- 

 hausts itself, or until the patient succumbs. 



The membrane of croup consists microscopically of amorphous or 

 finely-fibrillated fibrin, in which numerous young cells have been en- 

 tangled during the process of its excretion. 



The frequent association of pharyngeal croup with croup of the 

 larynx has a very important bearing, not only upon the diagnosis of the 

 disease, but also upon the physiological elucidation of its symptoms. 

 The French do not acknowledge any case as true croup, where this com- 

 plication is absent ; calling all others false croup. Since attention has 

 been called to the subject in Germany, it has been found that the co- 

 existence of both forms of the malady, although extremely frequent, is 

 by no means constant 

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