536 INFECTION AND IMMUNITY. 



Reports regarding the curative injection of 

 streptococci have been conflicting. It has been 

 found that the use of galactose as a means of kill- 

 ing the streptococci results in a better preservation 

 of antigenic properties than does the use of heat. 



Weaver concludes that the use of therapeutic 

 injections of galactose-killed streptococci is of 

 value only in subacute and chronic streptococcus 

 infections. 



The agglutinability of streptococci from differ- 

 ent sources, and even from the same source, varies 

 a great deal. Also the normal serums of man and 

 animals have a variable agglutinating power for 

 different strains of streptococci. By immunization 

 with a given strain the agglutinating power is in- 

 creased, but not uniformly for all strains. Com- 

 monly the strain used for immunization is agglu- 

 tinated more strongly than heterologous strains, 

 the latter sometimes undergoing no agglutination 

 whatever. These variations do not depend on dis- 

 coverable differences in the cocci or the diseases 

 which they produce. A given antistreptococcus 

 serum does not agglutinate equally all streptococci 

 from cases of scarlet fever (Weaver). Also strep- 

 tococci vary greatly in their ability to stimulate 

 to the formation of agglutinins. On the whole 

 those which produce long chains are more suscep- 

 tible to agglutination and yield stronger serums 

 than those with short chains (Aronson, Tavel, 

 v. Lingelsheim). By passage the agglutinating 

 properties undergo rather complex changes. The 

 organism then produces a stronger agglutinating 

 serum and is agglutinated more readily by this 

 serum than the same strain which had not been 



