162 



ESSENTIALS OF BACTERIOLOGY 



Patho genesis. 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 phleg- 

 monous condition arises, the capillaries be- 

 come 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 appear. 



Several varieties of the pyogenic staphylo- 

 cocci are recognized according to their color- 

 producing properties and slight variations of 

 growth. Of these, the Staphylococcus pyo- 

 genes aureus is the most virulent, and is con- 

 sidered 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 floor of houses. 

 Staphylococcus pyogenes albus differs 

 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. 



Micrococcus Pyogenes Citreus (Passet) . This liquefies 

 gelatin less rapidly than the pyogenes aureus, and forms a 

 citron-yellow pigment instead of the orange-yellow of the aureus. 

 Micrococcus Cereus Albus (Passet) .Differs from the 

 pyogenes albus in the form of colony. A white, shiny growth, 

 like drops of wax; hence the name, cereus. 



Micrococcus Cereus Flavus (Passet). A lemon-yellow 

 colored growth after a short time, otherwise not differing from 

 cereus albus. 



Micrococcus Pyogenes Tenuis (Rosenbach) . Origin. 

 Found in the pus of large inclosed abscesses. 



Fig. 97. Stab- 

 culture. Micro- 

 coccus pyogenes 

 aureus. 



