498 APPLICATION OF METHODS OF BACTERIOLOGY 



properties, producing various shades of yellow- and orange- 

 colored pigment, while others grow with a pink color. 



The occurrence of bacterium pseudodiphthetiticum in 

 pure culture in superficial abrasions showing a slight ten- 

 dency 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 suppurations occurring under 

 certain special conditions. With these facts in mind speci- 

 mens of pus were derived from thirty cases with suppurating 

 wounds in the University of Pennsylvania Hospital, and 

 careful bacteriological examination of these specimens 

 showed the presence of bacterium pseudodiphtheriticum in 

 43 per cent, of the cases. These organisms were always 

 found in conjunction with one or more of the group of pyo- 

 genic 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 acci- 

 dental invaders, but that in some way they contributed 

 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 sup- 

 port to the opinion that this group is of greater importance 

 than was heretofore supposed. Repeated passage through 

 guinea-pigs serves to so increase the pathogenic properties 

 of these organisms that they cause theMeath of the animal 



