314 Suppuration 



If the ear of a rabbit be carefully scarified, and cutaneously in- 

 oculated with a small quantity of a pure culture, local erysipelas 

 usually results, the disturbance passing away in a few days and the 

 animal recovering. If, however, the streptococcus be highly viru- 

 lent, the rabbit may die of general septicemia in from twenty- 

 four hours to six days. The cocci may then be found in large 

 numbers in the heart's blood and in the organs. In less virulent 

 cases minute disseminated pyemic abscesses are sometimes found. 



When mildly virulent cultures of the variety called Streptococcus 

 viridans are intravenously injected into rabbits, some time elapses 

 before much disturbance is noted, then the animal becomes ill and 

 eventually dies of cardiac disease. Verrucose endocarditis with 

 marked calcification of the mitral valve, with secondary metastatic 

 subacute glomerulonephritis was observed in those cases which were 

 carefully studied by Libman.* 



According to Marmorek,f the virulence of the streptococcus 

 can 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 milUarditme) 

 of a cubic centimeter injected into the ear vein was fatal. 



Petruschkyf 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. 



Holst§ 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 never 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 (iso- 

 dulcite) raffinose, inulin, amygdahn, arbutin, coniferin, digitalin, 

 helicin, populin, salicin, glycerin, sorbite and mannite (Gordon). 



* Amer. Jour. Med. Sci., ipio, cxl, 516; 1912, clxiv, 313; Trans. Asso. Amer. 

 Phys., 1912, xxvii, 157. 



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



t "Centralbl. f. Bakt. u. Parasitenk.," May 4, 1895, Bd.xvm,No. 16, p. 551. 



§ Ibid., March 21, 1896, Bd. xrx, No. 11. 



II Fliigge's "Die Mikroorganismen." 



