BACTERIOLYSINS AND IIMMOLYSINS 81 



antibodies to those which combine with other anti- 

 gens. 



According to Ehrlich the red blood cells possess 

 specific affinity for the immune body, or amboceptor, 

 but none whatever for the alexin or complement. 

 The complement, therefore, possesses no combining 

 group which can attach itself directly to the red 

 blood cell. It acts on these cells only through 

 an intermediary, the amboceptor which, therefore, 

 must possess two binding groups, one of which 

 attaches to the red blood cell and the other to 

 the complement of normal serum. As already 

 stated, the group which attaches to the red blood 

 cell possesses a much stronger affinity than that 

 which combines with the complement. This follows 

 from the last two experiments of Ehrlich before 

 cited, in which he showed that' at the lower tem- 

 perature, and with both substances present with the 

 blood cells, only the amboceptor combined with the 

 cells, while the complement remained uncombined. 

 At the higher temperature the complement also ex- 

 erted its affinity, for then the red cells combined with 

 all the amboceptor and with part of the comple 

 ment. We saw tljat after a time the red cells par- 

 tially dissolved, but that complete solution occurred 

 only after some fresh complement had been added. 

 This showed that although the red cells had com- 

 bined with all the amboceptor necessary for their 

 solution, they had been unable to bind all the corn- 



