356 Suppuration 



by the streptococcus more widespread in variola than in 

 any other disease. 



Virulence. In the great majority of cases, streptococci 

 isolated from human beings are pathogenic for rabbits and 

 mice. Rats become ill when injected with large doses, but 

 usually recover. Guinea-pigs, cats, and dogs are but 

 slightly susceptible. Large animals, like sheep, goats, cattle, 

 and horses, react very slightly to large doses, but sometimes 

 suffer from abscesses at the seat of injection. Mice die in 

 from one to four days from general infection. If the organ- 

 isms are less virulent, they die in from four to six days with 

 edema and abscess formation at the site of inoculation, and 

 subsequent invasion of the body. The streptococcus seems 

 to be most pathogenic for that species of animal from which 

 it has been isolated. 



If the ear of a rabbit be carefully inoculated 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 dies 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. 



According to Marmorek,* the virulence of the strepto- 

 coccus can be increased to a remarkable degree by rapid 

 passage through rabbits, and maintained by the use of a cul- 

 ture-medium consisting of 3 parts of human blood-serum 

 and i of bouillon. The blood of the ass or ascitic or pleu- 

 ritic exudates may be used instead of the human blood-serum 

 if the latter be unobtainable. By these means Marmorek 

 succeeded in intensifying the virulence of a culture to such 

 a degree that one hundred-thousand-millionth (un cent mil- 

 liardieme) of a cubic centimeter injected into the ear vein 

 was fatal to a rabbit. 



Petruschkyf found the virulence of the culture to be well 

 retained when the organisms were planted in gelatin, trans- 

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



Hoist J observed a virulent Streptococcus brevis that re- 



* "Ann. de 1'Inst. Pasteur," t. ix, No. 7, July 25, 1895, p. 593. 

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

 1895, P- 55i. 



% Ibid., Bd. xix, No. n, March 21, 1896 



