SECTION III 



PATHOGENIC MICROORGANISMS 



CHAPTER XXI 



THE STAPHYLOCOCCI (MICROCOCCI) 



The power to incite purulent and sero-purulent inflammations and 

 localized abscesses in man and animals is possessed by a large variety of 

 pathogenic bacteria. Most infections, in fact, in which the. relative 

 virulence of the incitant and the resistance of the infected subject are 

 so balanced that temporary or permanent localization of the infec- 

 tious process takes place are apt to be accompanied by the formation of 

 pus. The large majority of acute and subacute purulent processes, 

 however, are caused by the members of a well-defined group of bacteria 

 spoken of as the pyogenic cocci. Among these, pre-eminent in import- 

 ance, are the "staphylococci" or "micrococci." 



Many of the earher investigators of surgical infections had seen small 

 round bodies in the pus discharged from abscesses and sinuses and had 

 given them a variety of names. Careful bacteriological studies, how- 

 ever, were not made until 1879 and the years immediately following, 

 when Koch, Pasteur, Ogston,^ and others not only described morphologi- 

 cally, but cultivated the cocci from surgical lesions of animals and man. 

 Of fundamental importance are the studies published by Rosenbach ^ 

 in 1884, in which the technical methods of modern bacteriology were 

 brought to bear upon this subject for the first time. The group of 

 staphylococci — so named from their growth in irregular, grape-like 

 clusters — is made up of several members, by far the most important 

 of which, pathologically, is the Staphylococcus pyogenes aureus. 



Wgston, Brit. Med. Jour., 1881. 



^Rosenbach, "Microorganismen bei Wundinfektion," 1884. 

 321 



