372 INFECTION AND IMMUNITY. 



after the bacteria are introduced. By injecting 

 the vibrio of cholera and anticholera serum simul- 

 taneously one may readily save a guinea-pig from 

 ten times the fatal dose, or more. If the culture 

 be injected first and the serum later a larger 

 amount of serum is required to save the animal. 

 After a few hours a sufficient amount of serum to 

 kill all the vibrios may be injected, yet the ani- 

 mal will die from the action of the endotoxins 

 which have been liberated. The organisms had 

 proliferated to such an extent that the mass, 

 though dead, contained a fatal amount of endo- 

 toxin. A statement made previously may be re- 

 peated, that the administration of a bactericidal 

 serum rather than being beneficial may actually be 

 injurious, in that it dissolves the micro-organisms 

 rapidly, thereby liberating an excessive amount of 

 endotoxin, this, perhaps, is not definitely estab- 

 lished as a point of practical importance. 



Having determined the amount of a bactericidal 

 serum which is able to save a guinea-pig from an 

 incipient infection, one may calculate on the basis 

 of weight the amount which would be required to 

 save a man under the same conditions; frequently 

 it amounts to impossible quantities, hundreds of 

 cubic centimeters. The conditions are all the less 

 promising when we remember that physicians are 

 usually called on to treat well-established rather 

 than incipient infections. 

 peculiarities Other conditions which operate against the ef- 



of Coniple- , ..i i 



ment and fectiveness of bactericidal serums as curative 

 agentg haye to ^ w ^ peculiarities of comple- 

 ments and amboceptors. The lability of comple- 

 ment involves certain difficulties. A bactericidal 

 serum, as one would purchase it, contains none, 



