40 STREPTOCOCCI 



of their description and the failure of the author to mention 

 any character or property, or combination of the same, which 

 ■would distinguish it from others. However, such deficiencies 

 cannot well be avoided in the time of rapid accumulation ot 

 observations and the evolution of methods. 



§ 20. Classification of streptococci. A few investi- 

 gators have tried to eliminate the confusion concerning species 

 by classifying streptococci according to distinct morphologic 

 characters and pathogenic properties. Of these classifications 

 the following may be mentioned : 



I. The classification of von Lingelsheim. This author di- 

 vides all streptococci into two groups, or species, namely : — 



(a) Streptococcus bi'evis — which is non-pathogenic. 



{]]) Streptococcus longus — which is pathogenic. 



This is a combination of pathogenesis and morphology 

 which the author thought applicable to the entire genus. He 

 worked very largely, however, with the streptococci from the 

 human mouth and throat. 



II. The classification of Kurth. Kurth worked largely 

 with the streptococci from cases of scarlatina. His system is 

 practically the same as that of von Lingelsheim, with the ex- 

 ception that he does not include pathogenesis as necessarily 

 belonging to either group. The divisions are as follows : 



(a) Streptococcus rigidi — Streptococci growing in short 

 'Chains, imparting a uniform turbidity to bouillon. 



{J}) Streptococcus flexuosi — Streptococci which grow in 

 long interlacing chains forming flocculi in bouillon, leaving 

 the liquid clear. 



III. The classification of Pasquale. Pasquale worked with 

 thirty-three streptococci, including nearly all of the then 

 known species. His work was quite exhaustive, but he had 

 to deal with cultures of various generations. He divides them 

 into four groups, as follows : 



(a) Short saphrophytic streptococci. 

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