298 MICROBIOLOGY 



invaders together with other bacteria in old discharging 

 wounds. These bacteria are usually larger than that of diph- 

 theria and rarely show polar granules or bodies. Culturally 

 they show all the qualities of saprophytes. Inoculated into 

 animals they produce at most a mild local reaction. In the 

 literature these organisms have often been loosely spoken of 

 as "pseudo-diphtheria" bacilli, a term which is inappropriate 

 since they have nothing in common with the Klebs-Loeffler 

 bacillus except a certain morphological resemblance, and dif- 

 ferentiation is not difficult. 



SPECIES OF THE GENUS BACTERIUM WHICH CAUSE DISEASE IN 

 THE HUMAN SUBJECT. 



This genus contains a number of species such as Bact. 

 ahthracis, Bact. mallei and Bact. tuberculosis, that are patho- 

 genic for both man and for one or more species of the lower 

 animals. It also contains a number of species such as Bact. 

 rhusiopathiae, and Bact. suisepticum, that are not known to 

 infect the human subject at all. There are, however, a few 

 species in this genus that are pathogenic for man and not for 

 the lower animals, such as the bacterium of leprosy, and the 

 bacterium of human diphtheria. The latter has been reported 

 to cause disease in animals. 



