Bacillus Pyocyaneus 



331 



In some cases pus has a peculiar bluish or greenish color, which 

 depends upon the presence of Bacillus pyocyaneus of Gessard.* 



Distribution. — The bacillus appears to be a rather common 

 saprophyte, being found in feces, manure, and water. It easily 

 takes up its residence upon the skin and mucous membranes, and 

 has been found in the perspiration. It sometimes occurs as a sapro- 

 phyte upon the surgical dressings applied to wounds, and some- 

 times invades the tissues through wounds, to occasion dangerous 

 infections. 



Morphology. — It is a short, slender organism with rounded ends, 

 measuring 0.3 X i to 2 /t, according to Flugge; 0.6 X 2 to 6 /^, ac- 

 cording to Ernst, and 0.6 X 1 m, according to Charrin. It is quite 

 pleomorphous, which probably accounts for the difference in measure- 

 ments. It is occasionally united in chains of four or six. It is 



Fig. 



-Bacillus pyocyaneus. Colonies upon gelatin (Abbott). 



actively motile, has one terminal fiagellum, and does not form spores. 



It closely resembles a harmless bacillus found in water, and 

 known as Bacillus flourescens liquefaciens, from which Ruzickaf 

 thinks it has probably descended. 



Staining. — It stains well with the ordinary staining solutions, but 

 not by Gram's method. 



Isolation. — The isolation of the organism is simple, the ordinary 

 plate method being a satisfactory means of securing it from pus or 

 other discharges. 



Cultivation. — The organism grows readily upon all ordinary 

 culture media, under aerobic and anaerobic conditions and at tem- 

 peratures ranging from 18° to 45°C., the optimum temperature 

 being 37°C. 



Colonies. — The superficial colonies upon gelatin plates are small, 

 irregular, slightly greenish, ill-defined, and produce a distinct 

 fluorescence of the neighboring medium. 



*"De la Pyocyanine et de son Microbe," TMse de Paris, 1882. 

 f'Centralbl. f. Bakt. u. Parasitenk.," July 15, 1898, p. 11. 



