CHAPTER VIII. 



SERUM THERAPY 



In the discussion of theories of immunity, mention was made 

 of the fact that in 1887 Fodor showed that the juices of the nor- 

 mal Hying body, especially the blood, possess bacteria-destroying 

 property. Buchner, Behring, and Nuttall were among the first 

 to coroborate the results of Fodor. It was later recognized that 

 the cell-free blood serum of normal animals possesses properties 

 of destroying bacteria. It is to be noted, however, that the blood 

 of every species of animals will not destroy all species of bacteria. 

 Furthermore, while in certain cases the degree of natural immunity 

 corresponds to the amount of the bacteria-destroying substance 

 present, still these two conditions are not always found in the 

 same case. The substance which destroys bacteria, Buchner 

 called "alexine." 



In 1888 Hericourt and Richet made the observation that 

 blood serum from an animal immunized to Staphylococcus pyo- 

 septicus, confers when injected intraperitoneally into rabbits, 

 an immunity to this organism. Babes and Lepp in 1889 reported 

 the possibility of protecting animals against rabies by the injection 

 of body fluid from animals immunized to rabies. However, these 

 results were given but little attention until Behring and his 

 pupils systematically investigated the subject. 



Behring and Kitasato, in 1890, reported that mice can be im- 

 munized to tetanus by the injection of blood serum obtained 

 from rabbits artificially immunized to tetanus. These investi- 

 gators further reported that serum from tetanus-immune animals 

 protects against the primary intoxication produced by the tetanus 

 bacillus. 



In 1888 Roux and Yersin discovered diphtheria toxin. Beh- 

 ring and Wernicke, in 1891, showed that blood serum from diph- 



