INTERREACTIONS OF TOXIN AND ANTITOXIN 



2 4 6 8 10 12 14 16 -18' 



FIG. 21. CURVE OF NEUTRALIZATION OF DIPHTHERIA TOXIN (MADSEN). 



This table shows the difference between the observed and calcu- 

 lated results : 



The conclusion to which Arrhenius and Madsen came was that 

 toxin and antitoxin react like a weak acid and a weak base ; that 

 the reaction is a reversible one ; and hence that the combination 

 of toxin and antitoxin is an unstable one, dissociating into free 

 toxin and free antitoxin. 



