CHAPTER VII 



UDDER-STAPHYLOMYCOSIS 



The Infectious Organism 



The infectious organism is the pathogenic staphylococ- 

 cus pyogenes. 



The species name pyogenes which means pus producing 

 is becoming obsolete since the pathogenic staphylococcus 

 can cause necrosis without suppuration. 



Characteristics. — The pathogenic staphylococcus is a 

 small round microorganism which appears alone or in 

 groups of two or more, or presents square or irregularly 

 formed groups of individuals. They are easily stained 

 with the common anilin dyes and after Gram's method. 

 Their growth on cultm'c media is vigorous, especially the 

 surface growths. It liquefies gelatin and coagulates milk. 



Occurrence. — This coccus is similar to the streptococ- 

 cus in its geograpliical distribution and is present every- 

 where in Sweden. It is very common and appears fre- 

 quently in the dust of cow stables. 



Morphology. — The size of the pathogenic staphylococ- 

 cus is somewhat variable. There are large and small cocci. 

 As a rule it is one micron in diameter and somewhat 

 regularly globular in shape. It frequently occurs as a 

 single coccus or monococcus and also joined in groups. 

 These groups consist of two (diplococci) or more indi- 

 viduals, such as a four-sided group consisting of from four 

 to six individuals, or as an irregularly shaped gi'oup simu- 

 lating the arrangement of a bunch of grapes. These 

 groups consist of from 20 to 100 or more individuals. 



Not infrequently these cocci may also be arranged in a 

 line forming a chain, which is, however, short. The mono- 

 and diplococci occur in the greatest numbers, while the 



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