ANTI-STREPTOCOCCIC SERUM. 113 



the multiple would indicate. Attempts have also been made 

 to determine the protective value of specific anti -bacterial serum 

 by injecting varying amounts of sera, and bacteria, which have 

 been mixed in vitrio and allowed to act for some time before in- 

 jection. The value of some of the lytic serum, as determined by 

 this method, is high. Frequently it is not possible to test the bac- 

 tericidal power when, as a result of the difficulties of determining 

 the amounts of specific bactericidal substances in the serum, the 

 agglutinating and precipitating values are determined. This 

 method of standardization is not followed because agglutinins 

 and precipitins are regarded as bactericidal substances but because 

 these anti-bodies, to some extent at least, accompany bactericidal 

 power. 



As was stated earlier, specific anti-bacterial sera have been 

 made by injections of practically all the disease producing bacteria. 

 The most important of these are the sera which contain specific 

 substances by which they destroy streptococci, meningococci, 

 pneunococci, typhoid and dysentary bacilli, and staphlycocci. 



ANTI-STREPTOCOCCIC SERUM. 



Anti-streptococcic serum was first made bv Marmorek, in 

 1895. This investigator immunized horses by injections of in- 

 creasing doses of living virulent streptococci. With serum from 

 these animals he was able to confer passive immunity to rabbits 

 and also made attempts to treat erysipelas and pueperal fever in 

 the human. Denys and LeClef have immunized animals with 

 bouillon cultures of streptococci and claim to get favorable results 

 upon injection of serum from the immunized animals. Van der 

 Velde, realizing that there are different strains of streptococci, and 

 that the anti-sera produced are specific for the especial strain 

 used in immunization, immunized animals with the different 

 strains of streptococcic, thus making what is called a "polyvalent" 

 anti-streptococcic serum. 



The sera which are now on the market are almost universally 

 made by immunizing horses with repeated injections of increasing 



