TOXIC ACTION OF COMPLEMENTS 73 



ment is practically the same as that with guinea-pig's 

 complement ; (b) in the case of the immune-body acting on 

 guinea-pig's corpuscles, its dose is ten times greater with 

 guinea-pig's complement than with rabbit's complement ; 

 and, conversely, in the case of the immune-body acting on 

 rabbit's corpuscles, its dose is ten times greater with rabbit's 

 complement than with guinea-pig's complement. It is also 

 to be noted that the immune-body to ox's corpuscles does 

 not bring about complete haemolysis at all when the ox's 

 complement is used. 



These tables supply the hsemolytic doses of the different 

 immune-bodies and complements ; they do not, however, 

 give us the facts with regard to their several combinations. 

 In illustration of this we may mention that Ehrlich and 

 Morgenroth, 1 finding that the dose of the immune-body to 

 rabbit's corpuscles obtained from the guinea-pig was ten 

 times higher (as shown in the table) when rabbit's comple- 

 ment was used than when guinea-pig's complement was 

 used, supposed that there were really two immune-bodies, one 

 present in large amount taking up guinea-pig's complement, 

 and another present in small quantity taking up rabbit's 

 complement. This is manifestly a satisfactory theoretical 

 explanation, but we have to inquire whether it is supported 

 by facts ; as will be shown below, this is not the case. 



We shall accordingly consider the amounts of complement 

 taken up through the medium of different doses of immune- 

 body in the several cases. It will be convenient to take 

 first the second and third sera, as above arranged. The 

 method employed for estimating the amount of complement 

 taken up depends upon the firmness of union of complement, 

 and has been described above (p. 28). We take the amount 

 of complement absorbed as indicated by the point at which 

 free complement is first obtainable when the complement 

 is added in increasing amounts. 



1 Ehrlich and Morgenroth, Berlin. Win. Woch., 1900, No. 31. 



