NON-SPECIFIC PYOGENIC COCCI 191 



produced by them. The mixture of blood-serum, white blood- 

 cells, bacteria, and disintegrated tissue is called pus. 



Until recent times it was supposed that no wound could 

 heal normally and naturally without pus being produced; it was 

 regarded as a more or less essential step in the healing process. 

 When it was discovered that pus production was the result of 

 infection, and that healing by first intention (without pus formation) 

 was desirable, every effort was made to disinfect the wounds 

 made in surgical operations. This antiseptic surgery was un- 

 questionably an advance over that previously practised, but the 

 use of the strong disinfecting solutions irritated the tissues. At 

 present the surgeon uses every precaution to prevent the entrance 

 of extraneous bacteria into the wound, and dependence is placed 

 upon the natural resistance of the body and its immunizing 

 agencies to prevent the development of those organisms which 

 cannot be removed from the skin. This has been termed aseptic 

 surgery. 



While these organisms are usually associated with local inflam- 

 mation and suppuration, they may gain entrance to the blood- 

 stream and produce septicemia, pyemia, and metastatic infections 

 in many organs and tissues. 



Organisms Belonging to this Group. The organisms belonging 

 to this group may be subdivided into the Micrococci (Staphylo- 

 cocci) and Streptococci. The following species will be discussed: 

 Micrococcus aureus, M. albus, M. citreus, M. bovis, M. mastitidis, 

 M. ovis, M. epidermidis albus, M. cereus albus, M. cereus flavus, 

 Streptococcus pyogenes, and the closely related Streptococcus 

 lacticus. The student must expect to find in bacteriologic and 

 pathologic literature the greatest diversity of treatment of these 

 forms. It is important that the various synonyms of the names of 

 the more important organisms should be learned, that they may be 

 recognized hereafter. For example, the term Staphylococcus will 

 be found in literature quite as commonly as the form Micrococcus, 

 which is here used. It will be well before beginning the study of 

 the specific bacteria to read again the chapter on Classification of 

 Microorganisms. 



Common Characters. The organisms belonging to this group 

 resemble each other in being cocci, without spores, non-motile, 



