STREPTOCOCCUS PYOGENES 



235 



(6) S. equinus, present in the intestine of herbivora. They 

 do not assert that these are absolutely denned species ; 

 at the most they seem to be species in the making, and are 

 connected by transitional forms. Walker 1 does not con- 

 sider that these reactions afford a means of distinguishing 

 definite varieties among human streptococci. 



Andrewes and Horder give the following Table sum- 

 marising the characters of the various streptococci : 



+ = Positive or acid-production. = Negative or no acid-production. 



= Acid-production sometimes present, sometimes absent. 



(These differences are not constant ; with various strains one or other reaction 



may be lacking.) 



Crowe 2 makes use of Dorset's egg- medium with the 

 addition of 0-005 per cent, of neutral red for the purpose 

 of differentiating streptococci. 



The Streptococcus pyogenes is found in some 16 per cent, 

 of acute circumscribed abscesses. It is, however, especially 

 frequent in spreading inflammations, lymphangitis, cellu- 

 litis, and progressive gangrene, and is a common cause of 

 septicaemia, pyaemia, and puerperal fever, It is met with 

 in about one-third of the cases of infective endocarditis, 

 occasionally in acute osteomyelitis, and seems to be the 

 cause of the septic pneumonia so often observed after 

 operations about the mouth and throat. 



1 Proc. Roy. Soc. Lond., B. vol. Ixxxiii, 1911, p. 541. 

 3 Proc. Eoy. Soc. Med., vi, 1913 (Path. Sec.), p. 117. 



