PATHOGENIC BACTERIA 163 



Form. Cocci, without any especial arrangement. 



Properties. Not much studied. 



Growth. Cultivated on agar, it forms clear, thin colonies; 

 along the needle-track an opaque streak, looking as if varnished 

 over. 



Bacillus Pyocyaneus (Gessard) . Synonyms. Bacterium 

 aeruginosum; Bacillus fluorescens (Schroter); the bacillus of 

 bluish-green pus. 



Origin. Found in 1882 in green pus in pyocyemia. 



Fig. 98. Bacillus pyocyaneus, from an agar-agar culture (x 1000) (Itzerott 

 and Niemann). 



Form. Small slender rods with rounded ends, easily 

 mistaken for cocci. Often in groups of four and six, without 

 spores. 



Properties. Very motile; liquefy gelatin rapidly; a peculiar 

 sweetish odor and a blue pigment are produced in the cultures. 



Growth. Develops readily at ordinary temperature, growing 

 quickly and mostly on the surface; it is aerobic. Colonies on 

 gelatin plate: In two or three days a greenish iridescence appears 

 over the whole plate, the colonies having a funnel-shaped lique- 



