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. Asa 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 
