STREPTOCOCCUS PYOGENES. 489 



established. Having, then, in remembrance the above 

 facts, let us consider the results already obtained in the 

 experimental immunization and treatment of animals 

 and men suffering from or in danger of infection with 

 streptococci. One method is now chiefly used for the 

 immunization and attempt to produce curative sub- 

 stances in animals. The living, virulent streptococcus 

 itself is injected in gradually increasing doses. Mar- 

 morek 1 was the first to attempt to produce a curative 

 serum on a large scale. 



Influence of Serum from Animals Immunized Against 

 Streptococcus Infection upon Streptococcus Infections 

 in Other Animals. 



The results reported since Marmorek's commu- 

 nication in 1895 upon the immunizing effects of anti- 

 streptococcic serum in animals have been very vari- 

 able. 



Reliable positive results are, however, more impor- 

 tant than negative ones, since they indicate under 

 proper conditions what can be accomplished. This is 

 certainly true if at the same time we can find good 

 reasons for the failures reported. 



For the data in the following table I am indebted to 

 Anna W.Williams, assistant bacteriologist in the Health 

 Department Laboratories. For the use of the same I 

 wish to express my appreciation, 



In this present table are given the results following 

 the injection of small amounts of a serum which repre- 

 sents in immunizing value what about one-third of the 

 horses are able to produce. In the following experi- 



i Annales de 1'Institut Pasteur, July, 1895. 



