68 IMMUNE SERA 



mediation of the sensitizer that the alexin attaches 

 itself to the corpuscles; if this were the case the 

 removal of the sensitizer would necessarily imply 

 that of the alexin (complement) , which, as we have 

 just mentioned, does not leave the corpuscles. 



According to Ehrlich, however, the process is not 

 analogous to a staining process, but follows definite 

 laws of chemical combination, there being, in fact, 

 no affinity whatever between the complement and 

 the blood cells or bacteria. Furthermore, according 

 to this authority, the complement always acts 

 through the mediation of the immune body, which 

 possesses two combining groups; one, the cytophile 

 group, combining with the cell, and another, the 

 complementophile group, combining with the com- 

 plement. 



The Side-Chain Theory Applied to these Bodies. - 

 All of the specific relations which, in a previous 

 chapter, we saw existed between toxin and anti- 

 toxin, Ehrlich and Morgenroth in their experi- 

 ments above noted found existed also between 

 immune body and the specific blood cell. The 

 immune body must therefore possess a haptophore 

 group which fits exactly to certain receptors or 

 side chains of the red cells, just as the anti-body 

 according to the side-chain theory possesses a 

 group that fits exactly into the specific combining 

 group i.e., haptophore group of the toxin or 

 toxoid used for exciting the immunity. 



