304 BACTERIOLOGY. 



pered with cotton. The fluid should be allowed to 

 drop into the tube without running down the sides. 

 From 5 to 15 c.c. of fluid is a sufficient quantity for 

 examination." ^ 



BACILLUS PYOCYANEUS (BACILLUS OF GEEEN PUS). 



Another common organism that may properly be 

 mentioned at this place, though perhaps not strictly 

 pyogenic, is a bacillus frequently found in discharges 

 from wounds, viz., bacillus pyocyaneus, or bacillus of 

 green pus, or of blue pus, or of blue-green pus, as it 

 is variously designated. Bacillus pyocyaneus is a deli- 

 cate rod with rounded or pointed ends. It is actively 

 motile ; does not form spores. A s seen in preparations 

 made from cultures it is commonly clustered in irreg- 

 ular masses. It does not form long filaments, there 

 being rarely more than four joined end to end, and 

 most frequently occurs as single cells. 



It grows readily on all artificial media, and gives to 

 some of them a bright-green color that is most conspic- 

 uous where it is in contact with the air. This green 

 color, which becomes more and more marked as growth 

 advances, is not seen in the growth itself to any extent, 

 but is diffused through the medium on which the organ- 

 ism is developing. Ultimately this color becomes much 

 darker, and in very old agar-agar cultures may become 

 almost black (sometimes very dark-blue green, at others 

 brownish-black). 



Note. — To a fresh agar culture of this organism, in 



1 For a comprebensive treatment of this subject from its etiological 

 and pathological standpoints, see the monograph of Councilman, Mal- 

 lory, and Wright, to which reference was made above, and to which 

 we are indebtea for much contained in the foregoing sketch. 



