106 COLLECTED STUDIES IX IMMUNITY. 



be represented by immune body type b, which is activated by a 

 different complement also present in rabbit serum but found in 

 goat serum as well. Let the proportion of a: b be as 10: 1 ; i.e., a quan- 

 tity of immune serum containing one complete solvent dose of b 

 will contain ten solvent doses of a. In this case then it will require 

 ten times as much of the immune serum to effect complete solution 

 by means of immune body 6 (which is the case when goat serum, 

 which contains complement only for b, serves for reactivation) used 

 when immune body a is employed. The composition of this immune 

 ,serum can be represented by the formula 10a+16. 



/ 



FIG. 2. 



^H "tibkf 4kg^ ttjW ^^/ \*UL/ ^M& t&to iiifc' ^M ^fc4/k 



Diagram to show the two types of immune bodies present in the immune 

 serum of a rabbit treated with ox blood. Each immune body symbol corre- 

 sponds to one solvent dose for the amount of ox blood employed in the ex- 

 periment. Immune body type a is present in ten times the amount of type 6. 

 The complementophile groups of a and b differ; hence also the complements 

 differ. The anti-immune body serum possesses anti-immune bodies only 

 against a. 



As is seen by the experiments, an anti-immune body exists only 

 against immune body type a. If therefore to an amount of immune 

 body which contains one solvent dose of immune body b and ten 

 solvent doses of immune body a (i.e., 10a+ 16) a large quantity of anti- 

 immune body serum is added, and then sufficient suitable complement 

 it will be found that solution always occurs, for the reason that a 

 single solvent dose of b is present which is unaffected by the anti- 

 immune body although this was able to neutralize ten solvent doses 

 of a. One-tenth of the above amount of immune body, on the other 



