154 MODERN BIOLOGIC THERAPEUSIS 



junction with the amboceptor, or antibody, 

 which serves as an intermediary for fixing or 

 binding the complement to the cell or antigen on 

 which it acts. (4) HEMOLYTIC AMBOCEPTOR is 

 the lysin antibody of the serum of a rabbit 

 which has been immunized against sheep red 

 cells. (5) As the phenomenon of complement 

 fixation is invisible, BED BLOOD CELLS from the 

 sheep are used as an indicator of the reaction. 



Hemolysis In order to demonstrate fixation 

 of complement, the phenomenon of hemolysis is 

 brought into use. Hemolysis consists of the 

 breaking up of the red blood cells with the con- 

 sequent passing of hemoglobin into solution, the 

 originally opaque fluid becoming transparent. 

 The "hemolytic system" consists of three sub- 

 stances red blood cell suspension, hemolytic 

 amboceptor and complement; and the presence 

 of all three in definite proportions is necessary 

 for hemolysis. 



Principle Involved The reaction in comple- 

 ment fixation depends upon the fact that when a 

 specific quantity of antigen is mixed with the 

 proper volume of its homologous inactivated an- 

 tiserum, in the presence of a definite amount of 

 complement, all of the complement is firmly 



