20 EXPERIMENTAL RESEARCHES 



that the amboceptor and the complement stand 

 in direct relationship to one another. As a 

 matter of fact, from all sides proofs of the 

 existence of this direct relationship have been 

 advanced, and I think that the great majority 

 of my colleagues to-day accept my view, which 

 is known as the amboceptor theory. It is 

 true, as we have from the beginning insisted, 

 that the distributive relation of the complement 

 in the presence of the amboceptor is not that of 

 maximum chemical affinity ; indeed, we have, 

 on the contrary, as a rule an exceedingly loose 

 relationship which perhaps corresponds to a 

 reversible reaction. To show that this relation 

 is purposeful, we need only the following proof 

 amboceptors are already present in large 

 quantity and of various kinds in the blood- 

 serum of normal animals. What, then, would 

 happen if the entire mass of normal ambo- 

 ceptors reacted with pronounced avidity with 

 the complement ? Obviously the entire mass 

 of complement would be anchored by the com- 

 plementophile groups of the amboceptors, and 

 there would be no free complement present in 

 the living body. The grave results of such a 

 state of affairs are evident ; as soon as the 

 necessity for the action of complements with a 



