PART II. 

 SPECIAL BACTERIOLOGY. 



CHAPTEE XVI. 



WOUND INFECTION, SUPPURATION, AND THE COMMON 

 PYOGENIC BACTERIA. 



Pyogenic Bacteria. A large number of disease-producing bacteria, 

 after having entered and multiplied in the body of man and the 

 lower animals, may, under favorable conditions, lead to inflammatory 

 reaction with the formation of pus. A limited number, however, are 

 so frequently found as the cause of and associated with suppurative 

 processes that they are called the pyogenic bacteria. The word 

 pyogenic means pus-producing. The pyogenic staphylococci and 

 streptococci are the most common of these. The former, particularly, 

 are practically ubiquitous; they are found in the air, soil, water, and 

 on the external and internal gastro-intestinal surfaces of man and 

 animals. In the external world they ordinarily exist as saprophytes, 

 and, as a rule, cannot enter the body through a healthy skin or mucous 

 membrane. Absolutely clean wounds, such as are made by the sur- 

 geon with every possible aseptic precaution, will heal, as it is termed, 

 by primary (first) intention, and will not suppurate. Wounds, how- 

 ever, which are received under natural conditions, will suppurate 

 unless they are immediately cleansed with antiseptic solutions and 

 dressed to exclude the air and other possible sources of contamination. 

 The suppuration may vary in extent from being so scanty that it 

 can only be recognized microscopically to being so great that there 

 is a constant abundant discharge. The variations are dependent upon 

 the species of the infecting pyogenic organism and upon the greater 

 or lesser susceptibility of the infected race or individual. It is well 

 known that certain species of animals are very susceptible to certain 

 pyogenic organisms while others are entirely immune. 



When pyogenic bacteria are confined to a certain locality the process 



is known as a local infection. It may be so severe that a sufficient 



quantity of toxins are absorbed from the infected focus to produce 



grave general symptoms, including more or less high fever. There 



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