NONSPECIFIC INFLAMMATION 317 



In some eases the streptococci are grown in broth in 

 large quantities, and separated by centrifugation. An 

 apparatus working on the principle of a cream separator 

 has been devised and used for this purpose. 



A hemolytic toxin, streptolysin, has been demonstrated 

 for some strains of Streptococcus pyogenes, and for this 

 an antitoxin has been produced. However the antitoxin 

 has not been shown to have any curative or prophylactic 

 effect. It is not probable that the disease-producing power 

 of the organism can be accounted for on the basis of toxin 

 produced. So-called endotoxins are developed both by 

 virulent and by non-virulent strains. Bacteriolysins are 

 probably not important. Immunity is largely to be ascribed 

 to the activity of opsonins. 



Antisera prepared from horses by injecting first with 

 dead and then with living cultures of streptococci until a 

 high degree of immunity has been obtained, have been 

 claimed to be successful by some users. The results have 

 not, however, in general ppoved encouraging. In general 

 it may be stated that no very satisfactory method of im- 

 munizing against Streptococcus pyogenes has been devel- 

 oped. 



Staphtlococcus aureus and Staphylococcus albus 



Synonyms. — Staphylococcus pyogenes aureus and Staphy- 

 lococcus pyogenes albus, Micrococcus aureus and Micrococ- 

 cus albus, Aurococcus aureus and Albococcus albus. 



Morphology and Staining Characters. — These organisms 

 are considered together inasmuch as they are found in the 

 same general situations, are very closely related, differing 

 from each other only in minor characteristics such as pig- 

 ment production. These bacteria are spherical, occurring in 

 irregular masses like grape clusters. The cells are usually 

 0.7/i-0.9fi in diameter, occasionally larger. They are non- 



