JOINT ACTION OF AMBOCEPTORS IN HAEMOLYSIS. 607 



circumstances the free normal amboceptors, which act as anti- 

 complements (AC) come into play and deflect the complement 

 form the immune amboceptor (I A}. 



It is understood, of course, that in addition to these changes 

 in affinity, some significance must also be attached to the law of 

 mass action. Thus, if a very small quantity of normal ambo- 

 ceptors united to cells is placed beside an enormous number of 

 free anticomplements, it is possible that a deflection of complement 

 may occur. In dealing with native normal sera, such a dispropor- 

 tion is out of the question, for by increasing the quantity of anti- 

 complements there is also an increase in the amboceptors fitting 

 the cell. On the other hand, if the blood-cells have only been 

 slightly sensitized and when then large amounts of the inhibiting 

 serum are employed, a slight antilytic effect may be produced. 

 If due regard is given to the relative amounts of the factors, and the 

 blood-cells are sensitized with the proper proportion of normal 

 serum, no trouble will be experienced in observing the absence 

 of antilytic action against the normal amboceptor. For the sake 

 of completeness the following experiment is appended. 



Two series of test tubes are prepared, the first containing 0.1 

 cc. guinea-pig serum plus decreasing amounts of native rabbit 

 serum, the other containing the same amount of guinea-pig serum 

 plus decreasing amounts of rabbit serum which has previously been 

 absorbed with sheep blood-cells. To each of the tubes is added then 

 1 cc. 5% sheep blood-cells which have previously been sentisized 

 with 0.5 cc. normal rabbit serum, and separated from the serum 

 by centrifugalization. The result is shown in the following table. 

 The control with immune amboceptor is shown in Column I, Table II. 



TABLE III. 



