170 RELATIONSHIPS OF THE COCCACE^ 



by Houston (1905) associated with liquefaction of gelatin 

 and of the casein in coagulated milk. This type is there- 

 fore apparently most closely allied to Str. facalis ( Andrewes 

 and Horder). In the absence of more extended studies 

 of fermentative power it is impossible to characterize it 

 with any fullness. It may be provisionally denned as 

 follows : 



7. STR. GRACILIS (Escherich, Lehmann and Neu- 

 mann). Small coccus occurring in chains. Ferments 

 lactose and coagulates milk. May ferment salicin and 

 mannite. Liquefies gelatin, actively. 



The various streptococci which peptonize gelatin, more 

 or less actively, may be considered as variants of this 

 type, intermediate between it and some of those character- 

 ized by Andrewes and Horder. Under this head come 

 Str. coli (Escherich), Migula, Str. gracilis (Escherich), 

 Migula, Str. septicus (Babes), Migula, Str. urea (Rov- 

 sing), Migula, Str. trifoliatus (Rovsing), Migula, Str. 

 rugosus (Rovsing), Migula, Str. mni (Kramer), Migula, 

 M. liquidus, Migula, and M. decolor, Migula. 



Another peculiar form which we have twice found in 

 the course of our own investigations, and which may 

 possibly deserve specific rank, is Streptococcus sangui- 

 neus, described by Migula (1900), and distinguished by 

 the formation of a distinct brick-red pigment (intensely 

 blood-red according to Migula) in the stab, the surface 

 growth being colorless. The fact that old stab cultures 

 of streptococci sometimes showed a reddish-brown color- 



