318 



HISTOLOGY OF THE MORBID PROCESSES. 



acterized by the formation upon it of a " pseudomembrane " com- 

 posed chiefly of fibrin. 



7. Diphtheritic inflammation is a term usually applied to inflam- 

 mation affecting the tissues underlying a free surface. It is char- 

 acterized by local death of the superficial portions of those tissues 

 with an accompanying coagulation (Fig. 263). The result is the 



FIG. 281. 



Trwfc . ' />;-: ^>rT-v~r..T*V.^ -. . Q - 



" fe1lP' v \j;;S 



Catarrhal bronchitis : a, areolar tissue of the submucosa, infiltrated with serum and leuco- 

 cytes ; b, alveolus of a mucous gland, infiltrated at the periphery by leucocytes. The 

 epithelium is undergoing colliquative necrosis, and in the centre of the lumen are a few 

 leucocytes with fibrin, c, c', bloodvessels, c' shows an infiltration of the wall by emi- 

 grating leucocytes, d, muscularis mucosse ; e, subepithelial areolar tissue of the mucous 

 membrane, infiltrated with serum and leucocytes ; /, 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. 



formation of a membranous mass of dead tissue closely adhering 

 to the tissues beneath, a so-called "true membrane/ 7 in contradis- 

 tinction to the "false membrane" of croupous inflammation. This 

 membrane is subsequently separated from the underlying tissues by 

 the formation of granulations, leaving an ulcer. 



8. The " infective granulomata," such as tubercle, gumma, and the 



