192 



VETERINARY BACTERIOLOGY 



and gram-positive. They are all aerobic and facultative anaerobic, 

 and all grow, though in some cases poorly, upon most of the com- 

 mon laboratory media. 



Micrococcus aureus 



Synonyms. Micrococcus pyogenes aureus; Staphylococcus pyog- 

 enes aureus; Staphylococcus aureus. 



Micrococci were definitely described as present in pus by Ogston 

 (1881). Three years later Rosenbach (1884) cultivated them upon 

 artificial media and differentiated several species, among them the 

 one under consideration. Other investigators have frequently 



Fig. 82. Stained mount of the 

 Micrococcus aureus from agar (Gun- 

 ther). 



Fig. 83. Colony of Micrococcus 

 aureus on agar (Heim). 



isolated this organism from pus in man and practically all domestic 

 animals. 



Distribution in Nature. Micrococcus aureus occurs quite con- 

 stantly upon the skin and hair of man and animals, in the nose 

 and mouth of man, occasionally in human feces, and frequently 

 in milk. It is often carried about in atmospheric dust, and is 

 not uncommon in water, especially when contaminated with 

 sewage. 



Morphology and Staining Characters. The organism is 

 spherical, sometimes slightly flattened where two are appressed, and 

 in pus and in the blood is usually in masses like grape-clusters 

 (whence the name, Staphylococcus) ; in culture-media the cells are 



