416 BA CTERIOL OGY. 



definite chromogenic properties, producing various 

 shades of yellow- and orange-colored pigment, while 

 others grow with a pink color. 



The occurrence of bacterium pseudodiphtheriticum in 

 pure culture in superficial abrasions showing a slight 

 tendency to suppuration ; the fact that these organisms, 

 when injected into the peritoneal cavity of guinea-pigs, 

 produce purulent peritonitis; that such organisms are 

 frequently encountered in vaccine virus and in the pus 

 of vaccination wounds ; and that frequently in cases of 

 mastitis in cows such organisms occur in large numbers 

 in pure culture, has led to the supposition that this 

 group of organisms was probably responsible for sup- 

 purations occurring under certain special conditions. 

 With these facts in mind specimens of pus were derived 

 from thirty cases with suppurating wounds in the Uni- 

 versity of Pennsylvania Hospital, and careful bacterio- 

 logical examination of these specimens showed the pres- 

 ence of bacterium pseudodipthheriticum in 43 per cent, 

 of the cases. These organisms were always found in 

 conjunction with one or more of the group of pyogenic 

 organisms, and it is impossible to state how much of the 

 effect was due to any one of the organisms present. It 

 seems probable, however, in the light of what has been 

 said, that these bacteria were present not merely as 

 accidental invaders, but that in some way they contrib- 

 uted toward the results. 



The fact that some of the organisms isolated from 

 the pus, when inoculated into the peritoneal cavity of 

 guinea-pigs, show distinct pyogenic properties gives 

 strong support to the opinion that this group is of greater 

 importance than was heretofore supposed. Repeated 

 passage through guinea-pigs serves to so increase the 



