A Classification of Non-hemolytic Streptococci. by Ralph

No group of bacteria has been suspected of etiologic relationship with so many and diversified disease processes as the streptococcus. At the same time there is no group which suffers more confusion hi the relationship of its numerous members. The purpose of the present work was t o at tempt a classification of twenty-eight strains of non-hemolytic streptococci by a comparative study of their biochemical and immunological reactions. Since the streptococcus was first recognized as an infectious agent by Fehleisen (1) in 1882, various methods of classifying these organislns have been proposed. The object of every attempt to classify has been to determine whether all streptococci are identical with accidental differences in pathogenicity and cultural features or whether the differences noted constitute more or less fixed characteristics, which demand separate grouping for such members. All the schemes can be included in those dealing with morpholagy, the ability to produce special lesions, and immunological and biochemical reactions. Classification on the basis of morphology was abandoned early because of the influence which cultural environment was found to have on morphology. The terms longus (2), brevis, and conglomeratus (3) are now considered merely descriptive of growth phenomena and not of fundamental properties.