PSEUDO-DIPHTHERIA BACILLUS 213 



in three days if i c.c. of forty-eight has serum broth culture be 

 given subcutaneously. 



Certain of the pseudo-diphtheria bacilli, or " diphtheroids " as 

 they are called, seem to have the power of increasing or continuing 

 inflammation after it has been started by other germs. They are 

 frequently found in sinusitis, prostatitis, bronchitis, etc. In a few 

 reported cases they seem to have been the only micro organismal 

 cause of disease but their pathogenic powers are usually not great. 



PSEUDO-DIPHTHERIA BACILLUS 



Corynebacterium Pseudo-diphtheriticum. 



Pseudo-diphtheria Bacillus (Hoffmann). 



Morphology and Stains. This bacillus resembles the diph- 

 theria bacillus. The rods, however, are shorter and thicker; 

 otherwise, it stains like the true bacillus, but not by Neisser's 

 method. 



Culture. On glycerine agar the growth becomes diffuse, 

 spreading from the line of inoculation in a grayish-yellowish 

 pasty expanse. It grows well on gelatine. In bouillon it forms 

 a denser and more luxuriant growth than the bacillus. 



Habitat. It is found in healthy throats and conjunctivas. 



Pathogenesis. It is non-pathogenic for guinea pigs (see above). 



Diagnosis. It can be differentiated from the true bacillus by: 



1. Being non-pathogenic. 



2. Not exhibiting polar granules with Neisser's stain. 



3. Not producing acids in certain carbohydrate media. 

 Bacillus xerosis is a pseudo-diphtheria organism found on the 



normal conjunctiva. It is not thought to possess any virulence. 



TUBERCLE BACILLUS 



Mycobacterium Tuberculosis. 



Bacillus tuberculosis (Fig. 64). 

 Tubercle bacillus. 



