88 



DISEASES OF THE TRACHEA AND BRONCHI. 



DIAGNOSIS. Croupous inflammation of the bronchial mucous mem 

 Drane is easily distinguished from catarrhal inflammation by the expecto- 

 ration of characteristic moulds of the bronchial tubes, consisting of 

 coagulated fibrin. As the mucus from the finer bronchi may sometimes 

 have sufficient tenacity to retain its form, in doubtful cases, we may em- 

 ploy the test afforded by the different reactions of fibrin and muciii with 

 acetic acid, the fibrinous clot swelling up upon application of the dilute 

 acid, the mucus shrinking and becoming firmer. In well-marked cases 

 error is impossible. 



PROGNOSIS. Although the disease seldom attains such magnitude 

 as to endanger life, yet the prognosis as to complete recovery is unfa- 

 vorable. Bronchial croup is an exceedingly obstinate disease, evincing 

 a great tendency to relapse, and often becoming complicated at last by 

 tuberculosis, unless, indeed, this disorder accompany it from the outset. 



TREATMENT. The treatment is to be conducted upon the principles 

 .aid down for the management of laryngeal croup. In one case (Thier- 

 f elder), iodide of potassium afforded very marked and brilliant service 

 ( 3 ss daily), so that this treatment should be imitated. I have never 

 observed any benefit resulting from its action in this disorder. 



CHAPTER III. 



ESSENTIAL ASTHMA ASTHMA NERVOSIJM. 



[PATHOGENY AND ETIOLOGY. If the term asthma comprehends 

 all paroxysmal attacks of severe dyspnoea, regardless of their nature 

 or origin, we must draw a distinction between the so-called symp- 

 tomatic asthma, in which palpable disease of the bronchi, heart, or 

 lungs affords an explanation of the shortness of breath, and the es- 

 sential asthma, which exists independent of any local lesion capable 

 of accounting for the symptoms. 



Essential asthma, of which alone we now treat, is ascribable, 

 according to the present state of our knowledge, to a contraction of 

 the muscular fibres of the medium and smaller bronchial tubes in 

 short, to a spasm of the bronchi. The existence of bronchial mus- 

 cles is now proved ; and the smallest bronchi possess an especially 

 pronounced layer of transverse muscular fibres, which, at the point 

 of transition to the infundibula, develop into a regular sphincter 

 (Rindfleisch). Moreover, we find by experiment that distinct con- 

 tractions of the bronchi may be brought about by means of electri- 

 city, either through the par vagum or through the lungs directly. 

 Nevertheless, the doctrine of bronchial spasm as the prime cause of 

 essential asthma is even yet in dispute. 



