354 BACTERIOLOGY. 



bacillus is absent. This, or one similar to it, has been 

 described by Vincent. 1 It does not grow on artificial 

 media and is not pathogenic in animals. From its 

 presence in the false membrane of a number of cases, 

 it is believed to have some causal relation to them. 



These cases show most of the local appearances of 

 true diphtheria, the superficial necrosis of the epithe- 

 lium, the membrane of the glandular swellings. The 

 pseudomembranes may persist for from one to two 

 weeks, or even, in exceptional cases, longer. This 

 bacillus is apparently frequently present in the normal 

 throat, and is probably only able under certain favor- 

 ing conditions, such as syphilis, to produce lesions. 

 Nerve degeneration and paralysis do not follow an 

 attack. 



The pseudomembranous angina accompanying scarlet 

 fever, and to a less extent other diseases, may not 

 show the presence of diphtheria bacilli, but only the 

 pyogenic cocci, especially streptococci, or, more rarely, 

 some varieties of little known bacilli. The deposit 

 covering the inflamed tissues in these non-specific cases 

 is, it is true, usually but not always, rather an exudate 

 than a true pseudomembrane. The majority of these 

 cases, however, are mild affections, being only of im- 

 portance in adding to the severity of the disease which 

 they complicate. An exception should be made when 

 the larynx is affected, as here the lungs are often sec- 

 ondarily involved. The bacteria which occur in false 

 diphtheria are streptococci, staphylococci, diplococci, 

 and sometimes pseudodiphtheria bacilli or bacilli which 

 are morphologically and culturally distinct from the 



i Annales de 1'Institut Pasteur, August, 1899. 



