266 BAGTEBIOLOGY. 



special procedures noted above, its cultivation may be 

 continued upon the same medium ; but growth will 

 usually not be observed if it is transplanted to ordi- 

 nary nutrient gelatin, agar-agar, bouillon, or potato; 

 should it grow under these circumstances its develop- 

 ment will be very feeble. (Is this the case with com- 

 mon pus-producers?) 



Sixth, it has no pathogenic properties for animals, 

 while several of the pyogenic cocci, notably staphylo- 

 coccus aureus and streptococcus pyogenes, are usually 

 capable of exciting pathological conditions. (This is 

 less commonly true of streptococcus pyogenes than of 

 staphylococcus aureus.) 



BACILLUS PYOCYANEUS (BACILLUS OF GREEN 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., the bacillus pyocyaneus, or bacillus 

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

 is commonly called. The bacillus pyocyaneus is a deli- 

 cate rod with rounded or pointed ends. It is actively 

 motile; does not form spores. As seen in preparations 

 made from cultures it is commonly clustered together 

 in irregular masses. It does not form long filaments, 

 there being rarely more than four joined together end 

 to end, and most frequently not even two. 



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

 is diffused through the medium on which the organism 



