i68 



ESSENTIALS OF BACTERIOLOGY 



Staining. Very readily colored with ordinary stains; also 

 with Gram's method. 



Pathogenesis. When rabbits are injected with cultures of 

 this microbe into the knee-joint or pleura, they die in a day. 

 If injected subcutaneously, only a local action occurs, namely, 

 abscesses. 



If directly into circulation, a general phlegmonous condi- 

 tion arises, the capillaries become plugged with masses of 

 cocci, infarcts occur in kidney and liver, 

 and metastatic abscesses form in viscera 

 and joints. Garre, by rubbing the culture 

 on his forearm, caused carbuncles to ap- 

 pear. 



Several varieties of the pyogenic staph- 

 ylococci are recognized according to their 

 color-producing properties and slight vari- 

 ations of growth. Of these, the Staph- 

 ylococcus pyogenes aureus is the most 

 virulent, and is considered the type of the 

 group. They are always present on the 

 surface of the body, beneath the nails, in 

 the nose and mouth, in the dust of streets, 

 and on the floors of houses, and are found 

 in nearly all suppurative processes, whether 

 on the surface or internally. 



Staphylococcus pyogenes albus dif- 

 fers from the preceding only in the absence 

 of pigment and in its slight virulence. 

 Welch describes a variety constantly found both on the skin 

 and in its deeper layers, which he calls the Staphylococcus 

 epidermidis albus. 



Specific Therapy. Sera have been found of no special 

 value. 



Bacterins (Vaccines). Twenty-four-hour-old agar surface 

 culture killed by heating at 60 C. is emulsified with normal 

 saline solutions and injected for the treatment of boils, ab- 

 scesses, and acne. The cultures should be autogenous, i. e. y 



Fig. 79. Stab- 

 culture. Micro- 

 coccus pyogenes 

 aureus. 



