STREPTOCOCCUS PYOGENES. 487 



Production of Toxic Substances. There is no doubt 

 that this micrococcus causes fever, general symptoms 

 of intoxication, and death by means of toxic substances 

 which it forms in its growth; but what these substances 

 are whether they, are due to splitting up of animal 

 proteids, or are secretion-products, or whether they are 

 contained in the cell-bodies of the organism what 

 their composition is and how they are produced in cul- 

 tures we do not know. 



Susceptibility to Streptococcus Infection. As with the 

 other ever-present pus cocci, the staphylococci, which 

 have, as a rule, only slight virulence, the streptococcus 

 is more likely to invade the tissues, forming abscesses 

 or erysipelatous and phlegmonous inflammation in man 

 when the standard of health is reduced from any cause, 

 and especially when by absorption or retention various 

 toxic organic products are present in the body in excess. 

 It is thus that the liability to these local infections, as 

 complications or sequelae of various specific infectious 

 diseases, in the victims of chronic alcoholism, and con- 

 stitutional affections in those exposed to septic emana- 

 tions from sewers, etc.', and probably in many cases 

 from the absorption of toxic products formed in the 

 alimentary canal as a result of the iugestion of im- 

 proper food, or of abnormal fermentative changes in 

 the contents of the intestine, or from constipation, are 

 to be explained. 



Immunity. Knorr succeeded in producing a moder- 

 ate immunity in rabbits against an intensely virulent 

 streptococcus by injections of very slightly virulent 

 cultures. Pasquale was able to immunize these ani- 

 mals partially against septicaemia. Marmorek has 

 immunized sheep, asses, and horses against very large 



