SECTION II. 



PATHOGENIC BACTERIA. 



CHAPTER XII. 

 THE PYOGENIC COCCI. 



THE BACTERIA OF INFLAMMATION. 

 THE STAPHYLOCOCCUS GROUP. 

 Micrococcus Aureus. 



Staphylococcus Pyogenes Albus. 

 Staphylococcus Epidermidis Albus. 

 Micrococcus Tetragenus. 



Staphylococcus Pyogenes Citreus. Micrococcus Ovalis. 



THE BACTERIA OF INFLAMMATION. 



THERE is a group of bacteria which possesses in common the ability 

 to incite that type of infection which is commonly spoken of as inflam- 

 mation. A majority of these organisms are habitual parasites of man 

 living upon the exposed surfaces of the body, the skin and mucous 

 membranes chiefly: with respect to their pathogenic properties they 

 may be regarded as "opportunists," not as a rule requiring a well- 

 defined portal of entry through definite tissues to become invasive. 

 Any break in the continuity of the skin or a weakening or change in 

 the physiological state of a mucous membrane (frequently caused by 

 intracurrent infection) provides the necessary atrium for invasion of 

 the underlying tissues. 



Not only are these bacteria ordinarily unable of themselves to 

 locate and force an entrance to the tissues of their host ; after invasion 

 is accomplished they are unable to escape from the tissues in suffi- 

 cient numbers to cause progressive disease of like nature in other 

 hosts. They are locked up in the body, as it were, and eventually 

 perish. They have not perfected their pathogenic mechanism. (See 

 chapter on Parasitism.) 



Bacteria of the "opportunist" type may be raised to very con- 

 siderable pathogenic powers if artificially created atria of entrance to 

 and escape from the tissues are provided, as for example, by passage 



