380 GLANDERS ANTHRAX PYOCYANEUS 



bacilli measure but 0.3 micron and others as much as 1 micron. The 

 length varies between 1.5 and 4 microns, the average being about 2 

 microns. The organism is actively motile, and possesses a terminal 

 polar flagellum (monotrichic flagellation). Capsules and spores have 

 not been observed. Ordinary anilin dyes color the bacillus with mod- 

 erate intensity, and it is Gram-negative, although the gentian violet 

 is somewhat less readily removed by alcohol than from a majority 

 of Gram-negative bacilli, as Bacillus coli for example. 



Isolation and Culture. The organism grows readily and rapidly 

 upon ordinary artificial media, producing the characteristic pigments 

 in the presence of oxygen. The colonies on agar are round and measure 

 from 1 to 3 mm. in diameter after eighteen to twenty-four hours' 

 incubation at 37 C. The growth spreads rapidly, and the pigment 

 which becomes visible within eighteen hours dissolves in the medium 

 imparting a blue-green color to it. Gelatin colonies are not charac- 

 teristic in outline, but rapidly liquefy the medium, which becomes 

 green. A turbidity is visible within eight hours in broth and a pellicle 

 usually forms on the surface. A viscous, gray-brown sediment collects 

 at the bottom of the tube, and an ammoniacal odor is noticeable even 

 within twenty-four hours. The medium, particularly the upper layers 

 in contact with oxygen, becomes blue-green. Milk is coagulated, 

 the coagulum being slimy, and eventually partly or even completely 

 dissolved; the medium, at first yellowish, becomes green, then blue, 

 particularly in the upper layers. 



Bacillus pyocyaneus is aerobic, facultatively anaerobic. The opti- 

 mum temperature is 37 to 38 C.; development is sluggish below 18 

 C. and practically ceases at 43 to 44 C. 



Products of Growth. Chemical. The organism produces a relatively 

 large amount of ammonia from proteins and protein derivatives, 1 and 

 in milk. 2 



Pigments. Two pigments are produced by Bacillus pyocyaneus: 

 a water-soluble, green, fluorescent pigment similar in physical proper- 

 ties to that found in cultures of other fluorescent bacteria; and a 

 specific pigment, pyocyanin, which is insoluble in water but soluble 

 in chloroform. Pyocyanin, to which the empirical formula Ci 4 Hi 4 NO 2 

 has been ascribed by Ledderhose, 3 crystallizes from chloroform solu- 



iArmaud and Charrin, Compt. rend. Ac. so., 1891, cxii, 755, 1157; Kendall, Day, 

 and Walker, Jour. Am. Chem. Soc., 1913, xxxv, 1243. 



2 Kendall, Day and Walker, Jour. Am. Chem. Soc., 1914, xxxvi, 1948, 1963. 



3 Deutsch. Ztschr. f. Chir., 1888, xxviii, 201. 



