252 BACTERIOLOGY. 



lighting up diseased conditions ; but cultures that are 

 kept on artificial media for a long time may in part, or 

 completely, lose this power. 



When guinea-pigs or rabbits are inoculated subcuta- 

 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 subse- 

 quent inoculation 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 be inoculated with a virulent anthrax culture, 

 and soon after be 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 



