PUS-PRODUCING MICROORGANISMS 89 



called micrococci or staphylococci, and streptococci. 

 Certain members of the group of cocci may also do 

 other things than produce simple pus or abscesses. 

 These will be considered at the end of this chapter. 

 Bacteria other than cocci which can produce pus 

 are the colon bacillus, pyocyaneus bacillus, typhoid 

 bacillus. 



Staphylococcus Pyogenes Aureus. Of the micrococci 

 there is one particular species of importance which 

 by some bacteriologists has been divided into two 



FIG. 26. Staphylococcus. X 1100 diameters. (Park.) 



varieties because members of the group differ in their 

 ability to produce color in laboratory cultures and 

 because the one having a golden-yellow pigment is 

 somewhat more frequently found in pus. This color- 

 producing organism is called the Staphylococcus pyo- 

 genes aureus (the golden pus-producing coccus). See 

 Plate II for an idea of growth and color. It is about 

 2TiiTrTr of an inch across and appears under the micro- 

 scope as single individuals, pairs, but more frequently 

 in grape-like groups. It stains fairly well with most 



