Staphylococcus Pyogenes Aureus et Albus 311 



Morphology. — The cocci are small spheres measuring about 0.7- 

 i.o,;« in diameter. There is no definite grouping in either liquid 

 or solid cultures. It is only in pus or in the organs or tissues of dis- 

 eased animals that one can say that a true staphylococcus (bunch, 

 of grapes) grouping occurs. 



The organisms are not motile and have no flagella. They do not 

 form spores. 





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Fig. 102. — Staphylococcus pyogenes aureus (Giinther). 



Staining.— They stain easily and briUiantly with aqueous solutions 

 of the anUin dyes and by Gram's method. 



Fig. 103. — Staphylococcus pyogenes aureus. Colony two days old, seen upon 

 an agar-agar plate. X 40 (Heira). 



Isolation. — Staphylococci are easy organisms to isolate, and can 

 be secured by plating out a drop of pus in gelatin or in agar-agar. 



The colonies of Staphylococcus aureus differ considerably in 

 color, some being much paler than others. 



Cultivation.^ — The staphylococci grow well upon all the standard 

 culture-media either in the presence or in the absence of oxygen at 



iiw. 



