THE COMPOUND H^MOLYSINS 225 



ACTION OF DIFFERENT QUANTITIES OF IMMUNE-BODY ("DIVERSION") 



The effect is very evident. The maximum in the three 

 series occurs at about a = 80, 50, and 30 respectively. 

 This observation seems to agree very well neither with 

 the views of Bordet nor with those of Ehrlich. If the 

 catalytic agent were present in greater quantity, we 

 might expect a stronger action, but the reverse is the case 

 if a is greater than 100. Now according to Ehrlich's view 

 we might expect that the active substance, the hsemolysin 

 which is here preformed in the mixture and thus attacks 

 the corpuscles, should not decrease in quantity with in- 

 creasing concentration of immune-body, and therefore the 

 effect should be just as according to Bordet's theory. Ehr- 

 lich has accepted the following explanation given by 

 Neisser and Wechsberg for their experiment, in which the 

 bacteria were not attacked in the presence of an excess of 

 immune-body. " If a is large, there is a marked excess 

 over the quantity of alexin (b), so that all the alexin is 

 combined as lysin (ab) before the mixture is added. The 

 excess of a is then bound to the bacteria (e) and gives the 

 compound ea. If now the affinity of b for a is greater 

 than for ea, b will remain as lysin (ab) in the solution, and 

 Q 



