PUS-PRODUCING MICROORGANISMS 81 



pigment is somewhat more frequently found in pus. 

 This color-producing organism is called the Staphylo- 

 coccus pyogenes aureus (the golden pus-producing 

 coccus). See Plate II for an idea of growth and color. 

 It is about 2TTRTO of an inch across and appears under 

 the microscope in single individuals, pairs, and more fre- 

 quently, in grape-like groups. It stains fairly well with 

 most dyes used. It does not form spores and does not 

 move from place to place by its own power. It grows 



FIG. 25 



Staphylococcus. X 1100 diameters. (Park.) 



best about 85 F. It is killed about 56 C. or 130 F. 

 at ten minutes in the moist condition, but when com- 

 pletely dry it may require boiling to kill. When dried 

 on cloth or paper it may live three months. This 

 organism grows well on ordinary laboratory foodstuffs, 

 and produces, particularly in the presence of diffuse 

 light and oxygen, a golden yellow color. This coccus 

 has the property of coagulating milk and liquefying 

 gelatine by the ferments it produces. It is killed by 

 corrosive sublimate, 1 to 1000, in ten minutes in 

 6 



