584 COLLECTED STUDIES IN IMMUNITY. 



ditions existing among bacteria, we find the so-called group reactions 

 showing that the receptor apparatus and the antisera possess a highly 

 multiple constitution. This fact, as is well known, has here been of 

 great practical value. We see, therefore, that the plurality of the 

 amboceptors, so far as the cytophile group is concerned, is an assured 

 fact; the differentiation by means of antiamboceptors directed 

 against the cytophile group can therefore very well be foregone. 

 The production of antiamboceptors against the cytophile group seems 

 to encounter particular difficulties, for the complementophile group 

 always finds the corresponding counter group in the organism more 

 readily than does the cytophile group, and therefore is alone bound 

 by the tissue receptors. It is possible that in order to successfully 

 immunize with cytophile groups, it will be necessary to isolate these 

 groups. The latter might be accomplished by neutralizing the com- 

 plementophile group with the corresponding antibody, or by destroy- 

 ing this group ( = cytophilic amboceptoids). 



In any event these studies confirm the correctness of the ambo- 

 ceptor theory, i.e., that there is a direct combination of amboceptor 

 and complement. To repeat, therefore, the specificity of the ambo- 

 ceptors applies: 



(1) To the receptor employed in immunization, and this mani- 

 fests itself in the configuration of the rlaptopKore group ; and 



(2) To the animal species from which the amboceptor is derived. 

 The latter kind of specificity shows itself in the structure of the com- 

 plementophile apparatus, which, as we know, consists of a large 

 number of individual complementophile groups. To this plurality 

 of the complementophile groups there corresponds a plurality of com- 

 plements as can hardly longer be questioned. So far as the consti- 

 tution of the complement is concerned, the fact that it is made up of 

 a haptophore and a toxophore group is sufficiently proven by test- 

 tube experiments. The indirect method first employed for the 

 demonstration of the haptophore group, namely, by the production 

 of anticomplements, can therefore be dispensed with. 



However, I am convinced that just as normal body-fluids so often 

 contain anticomplements, it will also be found possible to produce 

 these by immunization. But as Moreschi has well pointed out, the 

 experiments by which it was sought to demonstrate the production 

 of anticomplements are not absolutely conclusive. Recent studies 

 by Gengou, Moreschi, and Gay have shown that in the immunization 

 with serum, antibodies directed against the albuminous constituents 



