BACILLUS PYOCYANEVS 379 



found heating the culture to 80 C. for fifteen minutes will destroy all 

 vegetative forms leaving the anthrax spores in excess and frequently 

 in pure culture. The growth on gelatin is fairly distinctive. 



(c) Inoculate a guinea-pig or a mouse with a small amount of blood 

 or fluid from a suspected lesion; if bacilli are not numerous, incubate 

 the material in broth for twenty-four hours, then inject the enriched 

 culture. The occurrence of typical large Gram-positive bacilli in the 

 blood stream postmortem is sufficient to establish the diagnosis in 

 the light of the clinical history. The principal organisms likely to 

 cause confusion are: B. subtilis and members of the mesentericus 

 group, which do not produce acute death in guinea-pigs by generalized 

 septicemia, and B. edematis maligni and B. aerogenes capsulatus, 

 both of which are obligate anaerobes. 



Dissemination. The spores of anthrax bacilli are extremely resis- 

 tant to dessication, and they remain alive for years in the soil. Once 

 a pasture or other enclosure is infected with the organisms it is unsafe 

 to permit cattle, sheep or other domestic animals to graze there. 

 The washings from such infected lands may convey infection to other 

 lands. 



Prophylaxis in man consists essentially in preventing contact infec- 

 tion with diseased animals or infected material, and particular care 

 in preventing the inhalation of dust from hides or wool of cattle or 

 sheep from countries where the disease is prevalent; this applies par- 

 ticularly to South American, Moroccan and Russian hides and wool. 



BACILLUS PYOCYANEUS. 



Historical. Surgeons for many years have noticed that occasional 

 suppurating wounds discharge pus which stains bandages a green or 

 green-blue color. Gessard 1 demonstrated the specific organism, Bacil- 

 lus pyocyaneus, in pure culture and described it in considerable detail. 

 Somewhat later Charrin 2 studied the pathogenesis of the organism for 

 rabbits (maladie pyocyanique), setting forth clearly the importance 

 of the bacillus as a disease-producing microorganism. 



Morphology. Bacillus pyocyaneus is a moderate-sized organism 

 with rounded ends, usually occurring singly or in pairs, less commonly 

 in short chains. The dimensions vary considerably even in the same 

 culture; the diameter averages about 0.6 micron, although some 



1 These de Paris, 1882. 



2 La maladie pyocyanique, Paris, 1889. 



