BRONCHIAL HAEMORRHAGE. 145 



tissue, caused by rupture of some of its large vessels, and causing de- 

 struction of the lung, with the formation of an apoplectic cavity. 



Haemorrhage from cavities and bleeding arising from the opening 

 of an aneurism into the air-passages are to be treated of hereafter. 



OHAPTEE VI. 



BRONCHIAL HAEMORRHAGE. 



ETIOLOGY. Wounds and erosions of the larger blood-vessels of 

 the bronchial mucous membrane are extremely rare. Capillary haemor- 

 rhages of the air-passages, too, are seldom of traumatic origin, or due 

 to sloughing or ulceration of the membrane. As a rule, haemorrhage 

 proceeds from rupture of the capillaries, caused either by over-disten- 

 tion, or else by a morbid delicacy of their walls, a result of perverted 

 nutrition. The trifling capillary haemorrhages which occur in the first 

 stage of acute bronchial catarrh, in cases of violent irritation of the air- 

 passages, and in tba circulatory disorder attending organic disease of 

 the heart, proceed from the first of these causes, while in most of the 

 haemoirhages, in which large quantities of blood are poured into the 

 bronchi, to be ejected thence by haemoptysis or bronchorrhagia proper, 

 they are due to the latter condition. 



The fact, which has been too little appreciated hitherto, that nearly 

 all bronchial haemorrhages are mainly owing to a morbid state of the 

 vascular walls to a haemorrhagic diathesis * of the bronchial mucous 

 membrane and do not depend upon over-filling of the vessels, is of 

 great practical importance. The truth of this is shown by the fact, not 

 only that attacks of haemoptysis and bronchorrhagia are not usually 

 preceded by bronchial hyperaemia, but that the spitting of blood almost 

 always persists, and, in fact, often does not assume an obstinate char- 

 acter until after the patient has lost a good deal of blood, so that his 

 vascular system is considerably depleted. 



A tendency to abundant bronchial haemorrhage to a haemorrhagic 

 diathesis, according to the above definition 1. Is met with in rare in- 

 stances, occurring unexpectedly in young persons, apparently in bloom- 

 ing health, and of vigorous constitution. In such cases, we as yet have 

 absolutely no explanation of the disorder, which is usually limited to 

 the capillaries of the bronchial mucous membranes, and which is often 

 followed by such sad results. 



* We employ this general term merely to signify a morbid tenderness of the vas- 

 cular walls, and not a morbid condition of the blood ; although we admit that the 

 latter may sometimes so modify the nutritive state of the walls of the blood-vessels a* 

 to impair their resisting power, and thus to lead to a haemorrhagic diathesis. 

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