TOXIC ACTION OF COMPLEMENTS 77 



body did not lead to the taking up of corresponding multiple 

 doses of complement, and (6) that the complement taken 

 up appeared to dissociate again in part, though this pheno- 

 menon might possibly be due to the presence of some com- 

 plement molecules with very slow action. When, however, 

 we used as the indicator ox's corpuscles treated with their 

 corresponding immune-body, quite different results were 

 obtained. The scheme is now : 



Guinea-pig's O + n IB + x rabbit's C ! + Ox's O + IB. 

 The following results will serve as examples : 



Experiment LX. 



1 dose of IB took up 0-2 c.c. rabbit's C. 

 3 doses 0-45 



10 ,, 1-16 



The M.H.D. of C was only 0-1 c.c. before the experiment; it is 

 possible that it may have increased subsequently. 



Experiment LXVIII. 



2 doses of IB took up 0-28 c.c. rabbit's C. 

 6 ,, 0-58 



10 0-74 



The M.H.D. of C was 0-06 c.c. 



It is thus seen that when ox's corpuscles suitably treated 

 are used as the indicator, the amount of complement taken 

 up increases as the amount of immune-body is increased, 

 though there is a greater deviation from strict arithmetical 

 proportion than when guinea-pig's complement is used. 



The difference hi the results obtained with the two indi- 

 cators (guinea-pig's and ox's corpuscles respectively), is 

 manifestly due to the fact that there is in the rabbit's 

 serum a complement which acts on guinea-pig's corpuscles, 

 and not on ox's corpuscles, and that this complement 

 either becomes dissociated from the guinea-pig's corpuscles 

 or combines in very small amount. On the other hand, 



