Wounds and Surgical Diseases 81 



or lodge upon surfaces of the respiratory or 

 digestive tract or in the heart and blood- 

 vessels which are already the seat of disease. 

 When they get into the hair follicles of the 

 skin, however, under certain conditions they 

 may incite boils. 



This is in brief the story of the bacteria 

 which most frequently induce the common 

 inflammations of the tissues, the compli- 

 cations in the healing of wounds, and the 

 varying phases of blood poisoning. 



As pus in greater or less quantity is apt 

 to be produced under these circumstances, 

 these bacteria are called the pus-forming or 

 pyogenic bacteria so they are named Staphy- 

 lococcus pyogenes and Streptococcus pyogenes. 

 (See Figs. 8 and 9.) 



Some other bacteria may occasionally in- 

 duce similar disorders in the body, but those 

 which have been described are the most 

 common and important. 



In addition to their power of inciting in- 

 flammation alone or together, the staphy- 

 lococcus and the streptococcus are so common 

 among city folks and those who live crowded 



