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principles of bacteriology 
VIII. Immune Treatment 
In acute infections serums from animals immunized 
with streptococcus vaccine has been, at times, very help¬ 
ful. The vaccine is of not much benefit. In chronic in¬ 
fections the vaccine is, at times, very useful. The vac¬ 
cine is prepared as the staphylococcus vaccine is. 
IX. Classification of Streptococci 
1. Streptococcus Pyogenes Longus—causes suppura¬ 
tive and septicemic lesions, occurs in long chains. 
2. Streptococcus Pyogenes Brevis—short-chained. 
3'. Streptococcus Haemolyticus—produces hemolysis 
on blood agar cultures. 
4. Streptococcus Viridans or Mitis—produces no 
hemolysis and much milder lesions—carious teeth, etc. 
5. Streptococcus Anginosus—occurs in throats of 
scarlet fever patients. 
Barely, if ever, pathogenic. 
6. Streptococcus Salivarius—found in the saliva. 
7. Streptococcus Fecalis—found in the intestines. 
8. Streptococcus Equinus—found in horses. 
X. Summary of Important Characteristics 
Gram-positive cocci, arranged in chains, nonmotile, no 
flagella, no spores, no capsules, grow poorly on ordinary 
media, well on “rich” media, cause hemolysis on blood 
agar plates; cause either local suppuration or systemic 
infection; very dangerous organism, enters through the 
skin, produces an endotoxin and a hemolysin. 
