Streptococcus Pyogenes 323 



According to Marmorek,* the virulence of the streptococcus cai^be 

 increased to a remarkable degree by rapid passage through rabbits, 

 and maintained by the use of a culture-medium consisting of 3 parts 

 of human blood-serum and i of bouillon. The blood of the ass or 

 ascitic or pleuritic exudates may be used instead of the human 

 blood-serum if the latter be unobtainable. By these means he 

 succeeded in intensifying the virulence of a culture to such a degree 

 that one hundred-thousand millionth {un cent milliardieme) of a 

 cubic centimeter injected into the ear vein was fatal. 



Petruschkyt found the virulence of the culture to be well re- 

 tained when the organisms were planted in gelatin, transplanted 

 every five days, and when grown, kept on ice. 



HolstJ observed a virulent Streptococcus brevis that remained 

 unchanged upon artificial culture-media for eight years without 

 any particular precautions having been taken to maintain the 

 virulence. 



Dried streptococci are said by Frosch and Kolle§ to retain their 

 virulence longer than those growing on culture-media. 



Metabolic Products.- — The streptococcus produces a ferment by 

 which milk is coagulated. A few streptococci (S. faecalis of And- 

 rewes and Horder) are said to produce gelatine softening ferments, 

 but this Streptococcus pyogenes nevet does. 



The organisms derive O from the atmosphere or from compounds, 

 but no gas is ever evolved in the process, though acids are always 

 produced in the presence of saccharose, lactose, rhamnose (isodulcite) 

 raffinose, inulin, amygdalin, arbutin, coniferin, digitalin, helicin, 

 populin, salicin, glycerin, sorbite and mannite (Gordon). No acids 

 are formed from starch, glycogen, arabin, convolvulin, huperidin, 

 jalapin, methyl glucoside, saponin, glycol, erythrite or dulcite 

 (Gordon). 



Marmorek|| and Lubenau** found that cultures of the strep- 

 tococcus when grown in bouillon containing glucose, produced a 

 hemolytic substance — streptokolysin — not seemingly present in 

 cultures grown in ordinary bouillon. Besredkaff found that strep- 

 tokolysin was produced only by highly virulent cultures of the 

 streptococcus and not by saprophytic organisms that have been 

 for some time under cultivation in the laboratory. 



LevinJI investigated the subject thoroughly and found that 

 different strains of streptococci produced streptokolysin in varying 

 quantities, that its production is entirely independent of virulence, 

 that it is destroyed by heat (37°C. in some days; SS°C. in one-half 

 * "Ann. de I'Inst. Pasteur," July 25, 1895, p. ix, No. 7, 593. 

 r'Centralbl. f. Bakt. u. Parasitenk.," May 4, 1895, Bd. xvin, No. 16, p. 551. 

 I Ibid., March 21, i8g6, Bd. xix, No. 11. 

 FIttgge's "Die Mikroorganismen." 

 "^Annales de I'Inst. Pasteur," 1895, 593. 

 "Centralbl. f. Bakt.," etc., 1901, Bd. xxx, Nos. 9 and 10. 



tt "Ann. de I'Inst. Pasteur," igoi, p. 880. 



H 'Nord. Med. Ark.," 1903, ir, No. 15, p. 20. 



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