STREPTOCOCCUS PYOGENES 349 



result. Hiss ^ indicated a tentative division of streptococci into those 

 which fermented monosaccharids alone, those which were also able 

 to ferment disaccharids, and those in which the fermentative powers 

 were extended to the polysaccharids, starch, dextrin, and glycogen. 



Gordon,^ after a thorough study of many strains upon seven carbo- 

 hydrates, found ten different fermentation reactions among twenty 

 pyogenic streptococci examined, and forty-eight different fermentation 

 reactions among two hundred streptococci isolated from saliva. Other 

 work by Andrewes and Horder and by Buerger ' confirms the irregu- 

 larity of the fermentation reactions within this group. 



Andrewes and Horder suggest the following classification: 



(1) Streptococcus 'pyogenes. A type which grows in long chains 

 and which ferments lactose, saccharose, and salicin, but does not coag- 

 ulate milk. Most of the streptococci which cause suppurative lesions or 

 severe systemic infections belong to this group. 



(2) Streptococcus mitis. A saprophytic type found frequently in 

 the mouth which shows the same cultural characteristics as the strep- 

 tococcus pyogenes, but grows in short chains. 



(3) Streptococcus anginosus. A type found frequently in the throats 

 of scarlet-fever patients which differs from the pyogenes only in coag- 

 ulating milk. 



(4) Streptococcus salivarius. A short-chain type which ferments 

 lactose, saccharose, and raffinose, and coagulates milk. Streptococci of 

 this type are found frequently in the mouth, but are rarely pathogenic. 



(5) Streptococcus fecaUs. A short-chain type which ferments lac- 

 tose, saccharose, and mannite. This type is found normally in the 

 intestine, and is occasionally pathogenic. 



(6) Streptococcus equinus. A short-chain type which does not 

 ferment lactose. It is found normally in horse dimg and is never 

 pathogenic. 



Quantitative determinations of the amount of acid formed in 

 various sugars by different races have also been made by Winslow 

 and Palmer ^ and others, but have led to no satisfactory classification. 



Studies by Hopkins and Lang seem to show that the streptococci 

 found in most human infections may be differentiated from the ordinary 



^Hiss, Cent. f. Bakt., xxxi, 1902; Jour. Exp. Med., vi, 1905. 

 ^ Gordon, Annual Report, Local Govern. Board, 33, London, 1903. 

 'Andrewes and Horder, Lancet, 1906; Buerger, Jour. Exp. Med., ix, 1907. 

 < Jour, of M. Pis., No. viii, 1910, 1, 



