412 



DIPHTHERIA 



situation necrosis of the epithelium occurs either uniformly or 

 in patches, and along with this there is marked inflammatory 

 reaction in the connective tissue beneath, attended by abundant 

 fibrinous exudation. The necrosed epithelium becomes raised 

 up by the fibrin, and its interstices are also filled by it. The 

 fibrinous exudation also occurs around the vessels in the tissue 

 beneath, and in this way the membrane is firmly adherent. In 



FIG. 116. Section through a diphtheritic membrane in trachea, 

 showing diphtheria bacilli (stained darkly) in clumps, and also 

 scattered amongst the fibrin. Some streptococci are also shown 

 towards the surface on the left side. 



Stained by Gram's method and Bismarck-brown, x 1000. 



the trachea, on the other hand, the epithelial cells rapidly 

 become shed, and the membrane is found to consist almost 

 exclusively of fibrin with leucocytes, the former arranged in a 

 reticulated or somewhat laminated manner, and varying in 

 density in different parts. The membrane lies upon the base- 

 ment membrane, and is comparatively loosely attached. 



The position of the diphtheria bacilli varies somewhat in 

 different cases, but they are most frequently found lying in oval 

 or irregular clumps in the spaces between the fibrin, towards the 



