AMBOCEPTOR, COMPLEMENT, AND ANTICOMPLEMENT. 261 



TABLE VII. 



The results of the experiments in the various cases are diametric- 

 ally opposite, for in one case there is a relation between complement 

 and amount of anticomplement required with different quantities of 

 amboceptor, in other cases there is a wide divergence. How are 

 these phenomena to be explained? 



To begin, let us assume for the sake of simplicity that comple- 

 ment and anticomplement are of simple constitution. In that case, 

 if, as all our experiments show, the affinity of complement is much 

 greater for anticomplement than for amboceptor, the neutralization 

 of complement and anticomplement should follow stoichiometric laws. 

 As a matter of fact this is what we found in the last case (Table MI). 

 In the first two cases, however, the results diverge so widely from 

 this, and are moreover so far beyond the limits which might be caused 

 by errors, that from this fact alone it necessarily follows that con- 

 ditions of affinity cannot by themselves suffice for an explanation. 

 We are therefore compelled to call to our aid another factor, one 

 which we have already emphasized, namely, the plurality of the comple- 

 ments and anticomplemcnts. 



Let us assume that in this case two dominant complements, 

 A and B, came into play in the complementing serum. The serum 

 serving as anticomplement must therefore contain the corresponding 

 anticomplement a or /?. It is self-evident that the corresponding 

 anticomplements are present in the isogenic serum; that they- may 

 also appear in the serum obtained by injection of a different serum, 

 e.g. of rabbit serum, is shown by previous experience. It is not at 

 all necessary to assume that rabbit serum contains exactly the same 

 complements A and B present in guinea-pig serum; it suffices to 

 assume a partial identity for the rabbit serum's complements (Ai and 

 BI], namely, an identity in the haptophore group. 



Following the terminology of the theory of numbers in which "friendly 

 numbers" (numeri amicabiles) are spoken of, one could designate complements 

 of different species which correspond in their haptophore groups, as "friendly 

 complements." 



