GROUP OF PYOGENIC COCCI. 43 



The aureus is the most virulent of all staphylo- 

 cocci. The infections caused by the staphylococci vary 

 with the virulence of the organism; and the resistance 

 of the individual infected. The infection may be local 

 like a boil or an abscess, or it may extend to involve 

 large areas of tissue (cellulitis). 



General infections, septicemia, and pyemia are 

 very often caused by these organisms. Malignant 

 endocarditis and puerperal fever come under this head. 

 They are usually the cause of infection in wounds, 

 although there are other bacteria that may do this. It 

 is to remove all bacteria, especially the pus-cocci 

 coming in contact with the patient, that the precau- 

 tions or technique of the operating-room is directed. 

 Since the pus-cocci are so often found on the skin, 

 careful washing and scrubbing of the hands followed 

 by a disinfectant is employed to destroy them. It is 

 important to remember that these precautions cannot 

 be safely performed in a careless manner, as the pyo- 

 genic cocci may be located in rather than on the skin. 

 They are to some degree resistant to* disinfectants, and 

 require an exposure of at least ten minutes in a i : 1000 

 solution of bichloride of mercury. 



The injury caused in infections by the staphy- 

 lococci is duo almost wholly to the toxins in part set 

 free and in part retained in their cell bodies, and 

 liberated in the dissolution after death. The toxins 

 cause the formation of pus and also' attack the red 

 blood-cells, dissolving them. This explains the anemia 

 that always accompanies these infections. 



