antigen-antibody reactions 

 Table 31 



445 



Arrhenius and Madsen pointed out that there is a 

 close similarity between this reaction and the purely 

 chemical reaction between ammonia and boric acid. 

 Ammonia is hsemolytic, and may be compared with the 

 toxin ; boric acid is non-hsemolytic and destroys the 

 lytic action of ammonia by formation of ammonium 

 borate, that is, it is analogous to antitoxin : — 



3NH4OH+H3BO4 ^==^ (N'H4)3B04 + 3HoO. 



They carried out a similar experiment with these reagents, 

 using the degree of haemolysis as an indication of the 

 amount of free ammonia, and again found a close agree- 

 ment between the observed and calculated values (Table 

 32), although here the degree of dissociation is consider- 

 ably higher than in the case of toxin and antitoxin. 



Table 32 



