236 BACTERIOLOGY. 



neously with 1 c.c. of virulent fluid cultures of this 

 organism death usually results in from eighteen to 

 thirty-six hours. At the seat of inoculation there, is 

 found an extensive purulent infiltration of the tissues 

 and a marked zone of inflammatory oedema. 



When introduced directly into the peritoneal cavity 

 the results are also fatal, and at autopsy a genuine 

 fibrinous peritonitis is found. There is usually an 

 accumulation of serum in both the peritoneal and pleural 

 cavities. At autopsies after both methods of inoculation 

 the organisms will be found in the blood and internal 

 viscera in pure cultures. 



"When animals are inoculated with small doses (less 

 than 1 c.c. of a bouillon culture) of this organism, death 

 may not ensue, and only a local inflammatory reaction 

 (abscess formation) may be set up. In these cases the 

 animals are usually protected against subsequent inocu- 

 lation with doses that would otherwise prove fatal. 



Most interesting in connection with the bacillus pyo- 

 cyanus is the fact, as brought out in the experiments of 

 Bouchard, and of Charrin and others, that its products 

 possess the power of counteracting the pathogenic activ- 

 ities of the bacillus anthracis. That is to say, if an 

 animal is inoculated with a virulent anthrax culture, 

 and soon after is inoculated with a culture of the bacillus 

 pyocyanus, the fatal effects of the former inoculation 

 may be prevented. 



In the literature upon the green-producing organisms 

 that have been found in inflammatory conditions, sev- 

 eral varieties — believed to be distinct species — have been 

 described, but when cultivated side by side their bio- 

 logical differences are seen to be so slight as to render it 

 probable that they are but modifications of one and the 

 same species. 



