1. Streptococci isolated from stools and from proctoscopic scrapings of patients exhibiting symptoms of colitis and of individuals with no colitis symptoms have been compared with five strains of streptococci commonly designated as Bargen’s “diplostreptococcus.” 2. The streptococci observed have fallen into ten different fermentative strains when grown in media containing inulin, mannitol, salicin, lactose, saccharose and raffinose, respectively. 3. Representatives of all the strains compared in this study have produced methemoglobin on blood agar plates, have resisted a temperature of 60° C. for thirty minutes, and have exhibited similar morphologic and cultural characteristics. None has produced intestinal lesions when injected intravenously into rabbits, though kidney lesions have been a common result of such injections. 4. By the use of mannitol and salicin only, it is possible to refer each of these ten strains to one of the following species of Andrewes and Horder:Str. faecalis, Str. mitis orStr. salivarius. By the additional use of lactose, saccharose or raffinose, several strains of each species have been recognized. 5. Agglutination reactions do not correlate to any appreciable degree with the ten fermentative strains listed. A closer relationship exists, however, when all strains which give the fermentation reactions ofStr. faecalis, Str. mitis andStr. salivarius respectively are grouped together. 6. No one strain has been associated more frequently with ulcerative colitis patients than with noncolitis patients. 7. Of the five strains of Bargen’s organism compared, one was identical with ourStr. faecalis II which is also identical withStr. faecalis of Andrewes and Horder; one withStr. faecalis IV which is a variant ofStr. faecalis; one is identical withStr. mitis of Andrewes and Horder, ourStr. mitis II; one with ourStr. mitis IV and two with ourStr. mitis I. Bargen’s strains in our hands did not exhibit any apparent differences from our strains in (1) the action on blood plates, (2) heat resistance qualities or (3) pathogenicity in rabbits. 8. There would, therefore, appear to be no reason to regard the streptococci described as Bargen’s diplostreptococcus as being essentially different from other types of alpha streptococci commonly recovered from the human alimentary tract and his strains may belong to the speciesStreptococcus faecalis, to Str. mitis toStr. salivarius.