376 BACTERIOLOGY. 



confined to portions of the tonsils in adults are not due 

 to the diphtheria bacilli, although a few cases presenting 

 these symptoms are. The more complete the involve- 

 ment of the tonsils the more apt the case is to be due 

 to them. Cases presenting the appearances found in 

 scarlet fever, in which a thin, grayish membrane lines 

 the borders of the uvula and faucial pillars, are rarely 

 diphtheritic. As a rule, pseudomembranous inflam- 

 mations complicating scarlet fever, syphilis, and other 

 infectious diseases are due to the activity of the patho- 

 genic cocci and other bacteria induced by the inflamed 

 condition of the mucous membranes due to the scarla- 

 tinal or other poison. But from time to time such 

 cases, if they have been exposed to diphtheria, may be 

 complicated by it, and in some epidemics mixed in- 

 fection is common. 



The Exudate Due to the Diphtheria Bacilli Contrasted 

 with That Due to Other Bacteria. As a rule, the exudate 

 in diphtheria is firmly incorporated with the underlying 

 mucous membrane, and cannot be removed without 

 leaving a bleeding surface, at least until convalescence. 

 The tissues surrounding the exudate are more or less 

 inflamed and swollen. Where other bacteria produce 

 the irritant the exudate, except in the cases due to the 

 bacillus described by Vincent, is usually loosely at- 

 tached, collected in small masses, and easily removable. 

 Exceptions, however, occur in both these diseases, so 

 that in true diphtheria the exudate may be easily re- 

 moved, and in lesions due to other bacteria the exudate 

 may be firmly adherent. 



Paralysis following a pseudomembranous inflamma- 

 tion is an almost positive indication that the case was 

 one of diphtheria, although slight paralysis has followed 



