STREPTOCOCCI IN COMPARATIVE PATHOLOGY. 
693 
He worked very largely, however, with the streptococci from 
the human mouth and throat. 
II. The classification of Knrth. * 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 be¬ 
longing to either group. The divisions are as follows : 
( a ) Streptococcus rigidi. —Streptococci growing in short 
chains, and which impart a uniform turbidity to bouillon. 
( b ) Streptococcus flexuosi —Streptococci which grow in long 
interlacing chains which form flocculi in bouillon leaving the 
liquid clear. 
III. The classification of PasqualeT 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 saprophytic streptococci. 
(/?) Long non-virulent streptococci. 
( c ) Long pathogenic streptococci. 
(<?0 Short highly infectious streptococci. 
Group ( d) pertains largely to bacteria which are no longer 
recognized as streptococci, for example, the diplococcus ( micro¬ 
coccus lanceolatus ) of pneumonia. It is now known that strep- 
tococci which grow in short chains are often virulent. This is 
especially true of the pyogenic forms. 
The study of streptococci from various sources, more especi¬ 
ally from tissues of diseased animals, suggests the desirability of 
delaying a classification until more definite data are obtained 
concerning the natural history, not only of these, but also of the 
species normally present on the mucous membranes of animals, 
and in nature generally. The specific name is, pathologically, 
or even biologically speaking, of little moment unless we can 
attach a certain definite meaning to its description which should 
*Arbeiten a. d. Kaiserlichen Gesundheitsamte, Bd. VII., (1891), S. 389. 
*Beitrage zur path. Anat. u. zur allgemeinen Pathologie, Bd. XII. (1893), S. 433. 
