334 



DISEASES OF THE RESPIRATORY ORGANS. 



ing lung tissue, are specially liable to be affected, constituting 

 lobular or catarrhal pneumonia. 



The mucous membrane of the bronchi is intensely red and 

 swollen. Upon the character of the inflammatory exudate 



FIG. 146. 



Catarrhal bronchitis, a, areolar tissue of the submucosa. infiltrated with serum 

 and leukocytes ; 6, alveolus of a mucous gland, infiltrated at the periphery by 

 leukocytes. The epithelium is undergoing colliquative necrosis, and in the 

 centre of the lumen are a few leukocytes with fibrin, c, c', blood vessels; c', shows 

 an infiltration of the wall by emigrating leukocytes ; d, muscularis mucosse ; 

 e, subepithelial areolar tissue of the mucous membrane, infiltrated with serum 

 and leukocytes; /, columnar epithelium of the surface in a state of colliquative 

 necrosis : g, exudate within the bronchus. In this portion of the bronchus the 

 destructive processes are so acute that the epithelium is destroyed, instead of 

 stimulated to the production of excessive mucus (Dunham). 



depends the appearance of the sputum. At first it is a glairy, 

 tenacious fluid containing a few leukocytes simply an exag- 

 geration of the normal secretion of the glands of the mucous 

 membrane. Later it becomes yellowish in color, muco- 



