150 RELATIONSHIPS OF THE COCCACE^E 



supposition that the secondary infections, characteristic 

 of this disease, are due to any specific streptococcus. 

 Here, as in scarlet fever and rheumatism, the streptococci 

 isolated from different cases of the same disease may often 

 show a distinct group relationship in their reaction to sera. 

 This has been shown for smallpox by De Waele and 

 Sugg (1903) and others. The phenomenon is, however, 

 a variable and uncertain one. Perkins and Pay (1903) 

 studied sixteen cultures of streptococci from variola, and 

 found several distinct varieties, varying in vigor of growth 

 on media, in action on lactose in milk, in formation of 

 turbidity in broth, and in agglutination reactions. 



It seems certain that group serum reactions are fre- 

 quently manifested by the streptococci associated with 

 specific pathological conditions. Even Meyer, one of 

 the strongest adherents of the "Einheit der Strep- 

 tokokken, " found , significant differences between the 

 behavior toward immune sera of the common pyogenic 

 streptococci and of the forms isolated from rheumatism 

 and scarlet fever (Meyer, 1902). These group differences, 

 however, affect only those highly variable qualities and not 

 the more constant morphological 'and biochemical proper- 

 ties. Even with regard to serum reactions themselves 

 the supposed specific differences are by no means universal. 

 Aronson (1903) gives a good summary of the data pre- 

 viously published on this point and adds the results of a 

 careful study of 27 different strains isolated from scarlet 

 fever, rheumatism, septicaemia, etc. Neither agglutination 



