252 



COLLECTED STUDIES IN IMMUNITY. 



The figures in Table I show that in the four similar cases here 

 examined the relation between the amount of amboceptor and of 

 the complement required is such that in the presence of larger amounts 

 of amboceptor smaller doses of complement suffice for complete haemolysis. 

 The relation is not exactly the same in the separate cases, as can 

 readily be seen from the figures of columns 2 and 4. In one case (I) 

 increasing the amboceptor eight times reduced the amount of com- 

 plement required only to , whereas in another case (IV) increas- 



o.b 



ing the amount of amboceptor only four times reduced the comple- 

 ment required to . This shows us at once that there is no definite 



ratio between the two factors. The causes of this varying relation 

 will be discussed later. 



The phenomenon in question is much less marked in the cases 

 reproduced in Table II, in which the combination was ox blood -f- the 

 amboceptor of specifically immunized rabbits + guinea-pig serum or 

 rabbit serum as complement. 



TABLE II. 



A. 1 cc. 5% Ox BLOOD + AMBOCEPTOR OF RABBITS TREATED WITH Ox BLOOD + 



GUINEA-PIG SERUM AS COMPLEMENT. 



