152 BACTERIA 



tions and absence of active pathogenic properties. It will appear 

 on nearly all plates made from sputum and throat cultures, in 

 crowded city life of temperate zones. It seems not to be able to 

 incite an infection but to continue or aggravate one already under 

 way. 



STAPHYLOCOCCUS PYOGENES AUREUS 



Staphylococcus Pyogenes Aureus (Fig. 39). 



Micrococcus Pyogenes. 



Staphylococcus pyogenes aureus, albus, and 'citreus are known 

 commonly as Staphylococcus, or grape coccus. They differ only 

 in color production on artificial media. 



FIG. 39. Staphylococcus aureus. (Williams.) 



The Micrococcus pyogenes aureus only is here described; the 

 other varieties have similar but much feebler pathogenic powers. 



Morphology and Stains. Round cocci, often growing in 

 bunches like grapes. Individual cocci dividing in two planes. 

 They stain very well with all basic dyes, and are not decolorized 



