UDDER-STAPHYLOMYCOSIS 55 



groups are less frequent and may be absent altogether 

 (Fig. 10). 



As previously stated, they are easily stained with the 

 common anilin dyes and following the method of Gram. 

 They are immotile and do not form a capsule. 



Cultivation. — The staphylococcus grows best at body 

 temperature ( ca. 38° C. ) . It also grows well at room tem- 

 perature. It grows aerobically and anaerobically, but 

 somewhat better aerobically, however. It can be cultivated 

 on the common media and grows well without serum. 



In the senim-gelatin-agar plates colony formation is 

 distinct after one day at 38° C. After two days the deep 



t • 



« 



Fig. 10. — Pathogenic 



staphylococci in croupous Fig. 11. — Colonies of staphylococci, a. Deep 



membrane from udder. colonies, b. Superficial colonies. Serum-gelatin- 



Gram. (X 550). agar plates. T. 38° C, 2 days (30). 



colonies in the last plate appear as sparse pinhead size 

 whitish-yellow, round or oval points. 



Upon microscopic examination with 30 diameters en- 

 largement they are opaque (black), coarsely granular and 

 in consequence of this granularity show a crenated margin. 

 Surface colonies are numerous and form porcelain-white 

 or yellow circular or at times irregularly formed, elevated 

 knob-shaped growths ca. 6 mm. in diameter (Fig. 11). 



The staphylococcils frequently produces a yellow pig- 

 ment by which the colonies, especially the surface colonies, 

 become a distinct yellow color. We differentiate the white 

 and yellow staphylococcus. The white staphylococcus 

 occurs more frequently than the yellow in our domesticated 

 animals. 



