STUDIES OX H.EMOLYSINS. 65 



pig blood inactive goat serum; sheep blood inactive dog serum; 

 sheep blood and inactive serum of goats treated with sheep blood. 

 In all these cases we have been able to determine that the reactivat- 

 ing action of the horse serum can be prevented by the addition of 

 small amounts of anticomplement serum (previously inactivated). 



In one case a very minute analysis of this action was made. The 

 factors in this case were rabbit blood and an interbody acting on 

 this, present in normal goat serum and obtained by heating the 

 serum to 56 C. The rabbit erythrocytes were first treated with 

 considerable amounts of this interbody and the excess of inter- 

 body was then separated by centrifuging the mixture and pouring off 

 the clear fluid. The erythrocytes thus loaded with interbody were 

 next digested with large amounts of the inactive anticomplement 

 serum and this likewise separated by centrifuging. The sedimented 

 blood-cells thus obtained dissolved completely on the addition of 

 horse serum. The same result was attained when the process just 

 described was performed in one act instead of in two; i.e., by mixing 

 the goat serum containing the interbody with the anticomplement 

 serum before the addition of the blood-cells. 



From this it follows that the antibody stands in relation neither 

 to the blood-cells themselves nor to the interbody. Even in the pres- 

 ence of the antibody the interbody is anchored in normal fashion by 

 the erythrocytes, and is furthermore not disturbed in its receptive 

 property for the complement. The antibody therefore has no 

 relation to either of the two haptophore groups of the interbody, and 

 it can only act by influencing the complement. 



The complement, however, according to our view, also possesses 

 two groups: one, a haptophore group, and a second which, in order 

 to express the analogy to the enzymes and toxins, we shall term the 

 zymotoxic group. Hence it still remained to determine into which 

 of these two groups the anticomplement fits. In either case, though 

 of course by a different mechanism, the action of the complement 

 would be inhibited; in one case by preventing the combination of 

 complement and interbody, in the other by preventing the zymo- 

 toxic action. 



If we assume that the anticomplement combines with the zymo- 

 toxic group, then the haptophore group of the complement will remain 

 free and must still be able to combine with the corresponding group 

 of the interbody. It would be expected, then, that the haptophore 

 group would combine with the interbody and "plug," so to speak, 



