Bacillus Pyocyaneus 365 



Morphology. It is a short, slender organism with rounded 

 ends, measuring 0.3 x i to 2 ^, according to Fliigge; 0.6 x 

 2 to 6 /w, according to Ernst, and 0.6 x i ^, according to 

 Charrin. It is quite pleomorphous, which probably accounts 

 for the difference in measurements. It is frequently united 

 in chains of four or six. It is actively motile, has one 

 terminal flagellum, and does not form spores. It can exist 

 without free oxygen, though it is an almost purely aerobic 

 organism. 



It closely resembles a harmless bacillus found in water, 

 and known as Bacillus fluorescens liquefaciens, from which 

 Ruzicka* thinks it has probably descended 





vi 



Fig. in. Bacillus pyocyaneus. Colonies upon gelatin (Abbott). 



Staining. It stains well with the ordinary staining solu- 

 tions, 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. Colonies. The superficial colonies upon 

 gelatin plates are small, irregular, slightly greenish, ill- 

 defined, and produce a distinct fluorescence of the neigh- 

 boring gelatin. 



Microscopic examination shows the superficial colonies to 

 be rounded and coarsely granular, with serrated or slightly 

 filamentous borders. They are distinctly green in the center 

 and pale at the edges. The colonies sink into the gelatin as 



* "Centralbl. f. Bakt. u. Parasitenk.," July 15, 1898, p. n. 



