202 DISEASES OF THE PARENCHYMA OF THE LUNG. 



found in the indurated tissue, which are undoubtedly to be regarded 

 as suppurating bronchiectases. 



Zenker, in a valuable treatise, shows that disease of the lungs may 

 also arise from the inhalation of iron-dust, which, in all essential par- 

 ticulars, is similar to anthracosis, differing merely in the nature of the 

 dust inhaled, and in the color of the lung, which is of a slate-coloi 

 instead of black. In one of the cases of this disease, reported by 

 Zenker, for which he proposes the name of siderosis, or of pneumono 

 Jconiosis siderotica (/), the oxide of iron, which had entered the lung, 

 had given rise to extensive induration and to the formation of large 

 cavities. 



RoJcitansky describes saccular dilatation of the bronchi as follows : 

 '* We find a bronchial tube widened into a fusiform, or rounded pouch ; 

 in the latter case the dilatation often being greater upon one side than 

 another, so that a greater part of the bronchial sac lies out of the 

 axis of the bronchial tube. In rare cases, the size of such a pouch 

 may equal that of a hen's egg. Often they would contain a bean, a 

 hazelnut, or a walnut. We further find either that any one of the 

 bronchial tubes may become expanded into a pouch of this kind, the 

 tube retaining its normal calibre upon either side of the dilatation, or 

 else quite a large tract of the bronchial ramifications may undergo 

 enlargement. Then, many such sacs of different size are so grouped 

 together that they form, as it were, a vast sinuous cave with manv 

 branches, whose individual pouches are bounded and separated from 

 one another by ledges or valvular folds of the bronchial wall." 



The inner surface of bronchiectatic cavities is at first smooth, the 

 mucous crypts having flattened out and disappeared through excessive 

 extension. The mucous membrane having thus gradually lost its char- 

 acter, becoming more like a serous membrane, its secretion also at first 

 bears some resemblance to that of a serous sac. We find in bronchi- 

 ectatic cavities a synovia-like liquid, resembling that found in a greatly 

 over-distended gall-bladder, or in an obstructed processus vermiformis. 

 At a more advanced stage, however, the inner surface often loses its 

 smooth character, and the contents of the cavity undergo change. 

 Owing to the unyielding condition of the surrounding parenchyma, 

 which is not compressed even by the most violent coughing, and par- 

 ticularly if the cavities are situated in the lower lobes of the lung, it 

 becomes extremely difficult to get rid of the secretion. Hence, the 

 latter, exposed to an elevated temperature, and in communication with 

 the atmosphere, is converted into a foul, yellow, stinking ichor, which 

 often acts as a corrosive upon the walls of the cavity, producing 

 sloughs and depriving the walls of their smoothness. It is not un- 

 common for severe haemorrhage to take piace when these slough? 



