ACTIVE IMMUNIZATION. 



Experiment. 



Second Fundamental Aggressin Test. 



(Its Property of Active Immunization.} 



Bail and his pupils believe that when bacteria invade a normal organism, 

 it is the aggressin power of these bacteria which determines whether or not, 

 by their multiplication disease will set in. If it does, the infection continues 

 until the "aggressive" nature of the bacteria is curbed. As there are some 

 bacteria which on injection do not produce any disease, Bail attributes this 

 phenomenon of immunity to the missing "aggressive" action of the respective 

 bacteria. It is not merely the presence of bacteria which is the criterion 

 for the existence of disease; as long as they are void of their "aggressive" 

 property, they have actually become saprophytes. 



Accordingly, Bail believes that the bactericidal immunity is no true 

 immunity because it can be obtained by injection of dead micro-organisms 

 or by live bacteria in such minute doses that no specific symptoms are pro- 

 duced, i.e., no aggressins are produced within the body. "If the immunity 

 lacks the "anti-aggressive" component, which alone governs the existence of 

 disease, one gains only an apparent immunity against the exciting factor of 

 the disease, but not against the disease itself." 



