VARIETIES OF STREPTOCOCCI. 175 



produces rapid septicaemia with death in a few hours, the 

 organisms being found in large numbers in the internal 

 organs. It has been proved by Marmorek's experiments 

 and those of others that the same species of streptococcus 

 may produce at one time merely a passing local redness, at 

 another a local suppuration, at another a spreading erysipe- 

 latous condition, or again a general septicsemic infection, 

 according as its virulence is artificially increased. Such 

 experiments are of extreme importance as explaining to some 

 extent the great diversity of lesions in the human subject 

 with which streptococci are associated. 



Varieties of Streptococci. Formerly the streptococcus 

 pyogenes and the streptococcus erysipelatis were regarded 

 as two distinct species, and various points of difference 

 between them were given. Further study, and especially 

 the results obtained by modifying the virulence, have shown 

 that these distinctions cannot be maintained, and now nearly 

 all authorities are agreed that the two organisms are one 

 and the same, erysipelas being produced when the strepto- 

 coccus pyogenes of a certain standard of virulence gains 

 entrance to the lymphatics of the skin. 



Petruschky in a recent publication has shown conclusively 

 that a streptococcus cultivated from pus may cause erysipelas 

 in the human subject. He obtained a pure culture of a 

 streptococcus from a case of purulent peritonitis secondary 

 to parametritis, the patient never having suffered from 

 erysipelas. By inoculations with this culture he produced 

 typical erysipelas in two women suffering from cancer. 



More recently a distinction has been drawn between a streplocowts 

 longus, which corresponds to the streptococcus pyogenes, as it usually 

 forms long chains, and is pathogenic to rabbits or mice, and a strepto- 

 coccus breviS) which occurs in the mouth in normal conditions and 

 is without pathogenic properties when tested experimentally. The 

 growth of the former in bouillon forms a somewhat granular deposit, 

 that of the latter a more abundant and flocculent deposit. Marmorek 

 has, however, found that the same streptococcus may at one time grow 

 in short, at another in long chains, and Kolle has shown that a strepto- 

 coccus, which originally grew in long chains, formed only short chains 

 after being repeatedly passed through the body of the mouse, the 



