JOINT ACTION OF AMBOCEPTORS IN HAEMOLYSIS. 



603 



in Column B, contained pig blood plus 0.015 of the specific ambo- 

 eeptor. The figures in each column denote: 



1. Native rabbit serum. 



2. Rabbit serum treated with sheep blood. 



3. Rabbit serum treated with pig blood. 



TABLE I. 



This table gives a beautiful illustration of the point noted by 

 Pfeiffer and Friedberger, namely, that the rabbit serum, which 

 has no antilytic properties whatever, exerts a specific antilytic 

 action after it has been treated with the corresponding blood-cells. 

 It is a simple matter to show that this antilytic action is not directed 

 against the amboceptors. One need merely mix amboceptor and 

 inhibiting serum, and then digest the blood cells in this mixture. 

 After centrifuging, it will be found that the sedimented blood-cells 

 are readily hsemolyzed on the addition of complement. This, 

 of course, shows that the amboceptor cannot have been affected. 

 Under these circumstances, and in the light of our past experiences, 

 we would ascribe the action to anticomplements, but in doing so 

 we encounter apparently a great difficulty, the specificity of action. 

 But is this specificity really irreconcilable with the assumption of 

 an anticomplement action? It seems to me that no such difficulties 

 exist in our case, and would ask the reader's attention to the fol- 

 lowing considerations : 



It can be shown that the inhibiting effect produced by a serum 

 after digestion with a particular species of blood (in our case with 

 sheep blood), is due essentially to the absorption of normal ambo- 



