THE STREPTOCOCCUS GROUP 305 
Products of Growth. — C7^e//?icfl/.— Streptococci exhibit but little evi- 
dence of proteolytic activity. No indol, skatol, phenol or other 
aromatic (lerivatives of amino-acids have been detected in cultures; 
gelatin is not liquefied and casein and coagulated blood serum are 
not visibly changed. Generally speaking, inulin is not fermented. 
Emmerlingi found peptone, leucin, tyrosin, ammonia, methylamine, 
propyl pyridin, succinic acid, butyric acid and other volatile acids 
among the anaerobic decomposition products of fibrin by this organ- 
ism, but no aromatic derivatives. These observations, however, are 
unconfirmed. 
Toxin.— A soluble toxin has not been demonstrated in cultures of a 
majority of streptococci, although substances have been isolated by 
Marmorek,2 Moser and others, which will kill guinea-pigs. These sub- 
stances do not exhibit sufficient potency to warrant the assumption 
that they are commonly important factors in the production of the 
Fig. 39. — Streptococcus in pus. X 800. 
grave symptoms characteristic of severe streptococcus infections. 
Attempts to demonstrate endotoxin have also been unsuccessful; the 
bodies of the organisms are but slightly toxic to experimental animals. 
The manifestations of toxemia in streptococcal infections, however, are 
too striking to be reconciled with the negative results of these investiga- 
tions; the nature of the mechanism of streptococcus infection remains 
to be elucidated. 
Ilemuli/sin — StreptGColysin. —Bordet^ and Besredka*' have shown 
that filtered broth cultures of streptococci will dissohe red blood 
corpuscles, liberating hemoglobin, and that this hemolytic substance 
— streptocolysin — is active both in vivo and in vitro. Frequently the 
blood of rabbits injected with streptocolysin was found to be "laked" 
just before death. Besredka's observations would indicate that the 
1 Ber. d. deutsch. chem. Gesellsch., 1897, 30, 186.3. 
2 Berl. klin. Wchnschr., 1902, 39, 253. 
3 Ann. Inst. Pasteur, 1897, 11, 177. " Ibid.. 1901, 15, 880. 
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