198 



WOUND INFECTION AND PYOGENIC BACTERIA 



cases. The killed staphylococci are injected in proper doses at 

 intervals of about six to eight days. If it is too troublesome to prepare 

 an autogenous vaccine, a stock vaccine, as prepared by pharma- 

 ceutical houses, may be used. 



STREPTOCOCCUS PYOGENES. 



Occurrence and Pathogenesis. Pyogenic streptococci are evidently 

 not found as commonly in the outside world as staphylococci, nor do 

 they appear to thrive as well as saprophytes. The Streptococcus 

 pyogenes is the cause of suppurative processes of all kinds, such as 

 septicemia, pyemia, puerperal infection, erysipelas, etc. General 

 infections by the Streptococcus pyogenes are, as a rule, even more 

 virulent than those of the staphylococcus. 



FIG. 112 



FIG. 113 



Streptococci from a pure culture in bouillon. Streptococci from human pus, Gram's stain. 

 X 1000. (Kolle and Wassermann.) X 1000. (Author's preparation.) 



Morphology and Staining Properties. The Streptococcus pyogenes 

 is non-motile, has no flagella, does not form spores, and can grow in 

 the presence or absence of oxygen. The individual cocci vary from 

 0.4 to 1 micron in diameter. The length of the chains differs so 

 much that varieties such as the Streptococcus pyogenes longus and the 

 Streptococcus pyogenes brevis, the long and the short chain cocci, 

 have been distinguished. The individual cocci forming the chain 

 vary not only in size but in shape. Some are entirely spherical; others 

 are flattened at both poles, so that the chain seems to consist of 

 disk-like bodies; still others are flattened out laterally, making the 

 individual cocci oval or like bacilli with pointed ends. When the cocci 

 grow in the long axis of the chain with infrequent division, chains are 

 formed which look much like streptobacilli, i. e., bacilli in the form of 

 chains. The formation of short or long chains is not an absolutely 



