22 EXPERIMENTAL RESEARCHES 



saving ; if the complement were already a con- 

 stituent part of the amboceptor, then as the 

 complement is easily destroyed there would 

 often be no action. The purposive saving is 

 evident from the fact that only in case of need 

 the amboceptor becomes able to combine with 

 the complement, and from the fact that com- 

 plementoids which, by reason of having lost the 

 zymotoxic group, become incapable of action, 

 have at the same time lost some of their avidity 

 for the amboceptor. By this change in the dis- 

 tributive quality of the complement that is 

 associated with the formation of complementoid, 

 the sphere of action of the amboceptor is con- 

 siderably extended. Of other possible influences 

 which may govern distribution and action we 

 have an indication given by the work of Ferrata. 

 Under Morgenroth's direction he carried out a 

 research, from which it appears that a comple- 

 ment is not a single body, one and indivisible ; 

 for in a salt-free medium it is split up into two 

 components, which are capable of action only 

 when they work in concert in a salt solution. 

 As to the intimate relations of these two com- 

 ponents, the researches which were carried out 

 at the suggestion of Sachs by Dr. Brand appear 

 to indicate that in the blood serum they are 

 always united. 



