260 THE MICROSCOPIST. 



softened matters, and appears in the expectoration (Fig. 

 212). Instead of resolution, in which the exudation is 

 absorbed or cast out by the sputum, abscess, or gangrene, 

 or chronic pneumonia may result, though rarely. 



Diphtheritic exudation accompanies a greater hypersemia 

 of the mucous surface than croupous inflammation, and 

 even of the submucous tissue, with a gangrenous separa- 

 tion of the infiltrated parts. Between the croupous and 

 diphtheritic forms of exudation there is every possible 

 transition. 



FIG. 212. 



Croupous pneumonia in a later stage of development. Melting down of the exudation. 

 Catarrhal desquamation of the alveolar walls. 1-300. After RIXDFLEISCH. 



Buhl regards diphtheritis as a general disease, which 

 may be termed acute tissue necrosis, and is different from 

 inflammatory, typhous, scarlatinous, or other forms of 

 tissue necrosis. 



The occurrence of fungi in diphtheritic exudation is 

 almost constant. The leptothrix buccalis is the most com- 



