216 BACTERIA PATHOGENIC TO MAN 



mild diphtheria very frequently occurs with the semblance of rather 

 severe ordinary follicular tonsillitis, due to the pyogenic cocci, and in 

 large cities where diphtheria is prevalent all such cases must be watched 

 as being more or less suspicious. As showing doubt in our judg- 

 ment, I think most would feel that if in any case exposure to diphtheria 

 is known to have occurred, even a slightly suspicious sore throat would 

 be regarded as probably due to the diphtheria bacilli. If, on the other 

 hand, no cases of diphtheria have been known to exist in the neighbor- 

 hood, even cases of a more suspicious nature would probably not be 

 regarded as diphtheria. 



Appearances Characteristic of Diphtheria. The presence of irregular- 

 shaped patches of adherent grayish or yellowish-gray pseudomembrane 

 or some other portions than the tonsils is, as a rule, an indication of the 

 activity of the diphtheria bacilli. Restricted to the tonsils alone their 

 presence is less certain. 



Occasionally, in scarlatinal angina or in severe phlegmonous sore 

 throats, patches of exudate may appear on the uvula or borders of the 

 faucial pillars, and still the case may not be due to the diphtheria bacilli; 

 these are, however, exceptional. Thick, grayish pseudomembranes 

 which cover large portions of the tonsils, soft palate, and nostrils are 

 almost invariably the lesions produced by diphtheria bacilli. 



The very great majority of cases of pseudomembranous or exudative 

 laryngitis, in the coast cities at least, whether an exudate is present in 

 the pharynx or not, are due to the diphtheria bacilli. Cases in which 

 no exudate is apparent and those in which the laryngeal obstruction is 

 sudden and the spasmodic element is marked are, however, frequently 

 due to the activity of other bacteria. Nearly all membranous affec- 

 tions of the nose are true diphtheria. When the membrane is limited 

 to the nose the symptoms are, as a rule, very slight; but when the naso- 

 pharynx is involved the symptoms are usually grave. Ordinarily a 

 small area of inflammation indicates a slight or moderate severity, 

 and an extensive area a severe infection. 



Most cases of pseudomehibranes and exudates, entirely 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 com- 

 plete the involvement 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 

 inflammations complicating scarlet fever, syphilis, and other infectious 

 diseases are due to the activity of the pathogenic cocci and other bac- 

 teria, induced by the inflamed condition of the mucous membranes 

 due to the scarlatinal 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 infection is common. 



Exudate Due to the Diphtheria Bacilli Contrasted with that Due to 

 other Bacteria. As a rule, the exudate in diphtheria is firmly incor- 

 porated with the underlying mucous membrane, and cannot be removed 



