24 EXPERIMENTAL RESEARCHES 



In practice, too, we have a further advantage 

 in the fact that the increase of avidity affects 

 not one complement alone, but, as a rule, all the 

 complements circulating in the blood. For the 

 complement-deviation test we may then choose 

 at will a complement which exercises any special 

 function, and, merely on practical grounds, we 

 choose haemolytic complements. The peculiar 

 power of the amboceptor to fix a large number 

 of complements, is not to be wondered at 

 in view of the biological function of the ambo- 

 ceptor. This I hold to be, under physiological 

 conditions, that of seizing upon and elaborating 

 nutritive substances. By its cytophile group 

 the amboceptor is enabled to combine with 

 substances of the most varied kinds, provided 

 that they possess fitting receptors. We have, 

 then, merely an increase of purposive function 

 in the fact that the amboceptor is furnished 

 with a host of complementophile groups which 

 enable the most varied kinds of complement to 

 act it may be simultaneously. This is the 

 consequence of the multiceptive nature of the 

 amboceptor. 



As regards increase of avidity, the fact that 

 the anchoring of the amboceptor to the cell 

 causes the avidity for the complement to be 



