JOINT ACTION OF SEVERAL AMBOCEPTORS. 625 



by employing an excess of ox serum, or by employing the min- 

 imum complete solvent dose of horse serum for the preliminary 

 treatment of the guinea-pig blood-cells. In contrast to this, the 

 blood-cells which have been previously treated with horse serum 

 only then fail to hsemolyze on the addition of ox serum plus horse 

 serum when the amount of horse serum used for the preliminary 

 treatment is excessive. As we have seen, Bordet and Gay regarded 

 the resistance of the cells against ox serum alone and against the 

 combined action of ox serum and horse serum as having a common 

 origin. From what has been said it is apparent, however, that 

 these phenomena will have to be considered separately. In the 

 former case complement is absent, and the inhibition, is therefore 

 absolute. In the latter case complement is present, the absence 

 of haemolysis being a secondary effect dependent on quantitative 

 relations. In the case described by Ehrlich and Sachs, in which 

 guinea-pig blood is haemolyzed by inactivated ox serum and horse 

 serum, we do not see the least reason for abandoning the explana- 

 tion offered by the authors. According to this, it will be remem- 

 bered, the amboceptor is contained in the ox serum. In this com- 

 bination it is absolutely unnecessary to assume the existence of 

 a third component which takes part in the ha?molytic action. 



Nevertheless we sought to find additional evidence to show 

 that the two components of horse serum and inactive ox serum 

 were directly related to one another, or that the amboceptor con- 

 tained in horse serum played no part in the haemolysis. In this 

 we were successful in more ways than one. If it is necessary for 

 ox amboceptor and horse complement to first unite and form an 

 active haemolysis before combining with the cell receptors, we should 

 expect that haBmolysis would result more quickly if horse serum 

 and ox serums were digested for a time before adding the blood, 

 than if all three components were mixed at once. We therefore 

 proceeded as follows: 



Two series of tubes were prepared: 



Series A. Decreasing amounts of horse serum (total volume 0.75 cc.) were 

 kept for one hour at 37. Then 1 cc. 5% guinea-pig blood plus 0.5 cc. inactive 

 ox serum are added to each tube. 



Series B. Decreasing amounts of horse serum are digested for one hou? 

 at 37 with 0.5 cc. inactive ox serum, after which 1 cc. 5% guinea-pig blood 

 is added to each tube. 



The degree of haemolysis was noted at the end of 5, 15, and 30 minutes 

 and after two hours. The result is shown in Table V. 



