Il6 RELATIONSHIPS OF THE COCCACE^ 



varieties were described. The organisms found in the 

 throats of healthy persons could not be distinguished 

 from those in the throats of pneumonia cases. Aggluti- 

 nation reactions were not sufficiently specific to be of any 

 assistance in separating the varying types. 



Finally Hiss (1905), at the central laboratory of the 

 commission, made a comparative study of two hundred 

 and sixty distinct organisms, obtained largely from the 

 individual observers previously cited. He distinguished 

 eight different types, according to variations in morphol- 

 ogy, acid production, and agglutination reactions, four 

 showing the diplococcus morphology, fermenting inulin 

 and reacting with pneumococcus sera, and the other four 

 showing the streptococcus morphology, failing to act on 

 inulin, and not agglutinated by pneumococcus serum. 

 Differences in the shape of the cells, in the capsule and in 

 the action on blood agar distinguished minor groups; 

 but the only sharply marked variety was the Str. mucosus, 

 differentiated from D. pneumonia by chain formation 

 and by its large, smooth, shiny colonies. Other variants 

 differed from the pneumococcus by the absence of cap- 

 sules alone, and others again differed from the strepto- 

 coccus only by fermenting inulin. The Schottmuller 

 reaction appeared less specific for the pneumococci than 

 the action upon inulin. 



Variability is evidently great among the pneumococci, 

 as elsewhere in the Paracoccaceae. Kruse and Pansini 

 (1892), not long after the first discovery of the organism, 



