JOINT ACTION OF SEVERAL AMBOCEPTORS. 629 



III. 



Our further efforts had, naturally, to be directed to a study of 

 the experiment reported by Bordet and Gay which forms so 

 important a link in their demonstration. It is based on the unique 

 observation that ox blood laden with specific amboceptor does not 

 dissolve in horse serum, but does so in a mixture of active horse 

 serum and inactive ox serum. It is true that there is a certain 

 external analogy between this phenomenon and the haemolysis of 

 guinea-pig blood by the same mixture. In the haemolysis of the 

 sensitized ox blood it is impossible that the ox serum acts as ambo- 

 ceptor, and this leads Bordet and Gay to conclude that in the 

 haemolysis of the guinea-pig blood the ox serum does not act as an 

 amboceptor. We have already seen that this conclusion is not 

 warranted. It was felt, however, that it would be interesting to 

 inquire more closely into the peculiar mechanism of the haemolytic 

 action in the ox-blood combination, the more so since the view of 

 Bordet and Gay, that the ox serum represents a "colloid" which 

 dissolves the blood-cells previously prepared by amboceptor and 

 complement, is an assumption devised for this particular case, and 

 one which would constitute an entirely new kind of serum haemolysis. 

 We therefore sought to find an explanation for the haemolysis in 

 in question on the basis of phenomena previously observed. 



In our experiments we used an inactivated immune serum 

 derived from a rabbit which had been immunized with ox blood. 

 One cubic centimeter 5% ox blood was just completely dissolved 

 (in the presence of 0.1 cc. guinea-pig complement) by 0.0005 cc. of 

 this specific immune serum. In order to effect haemolysis of ox 

 blood by the mixture "horse serum plus inactive ox serum" it was 

 necessary to use 0.05 cc. amboceptor. In the following experiment, 

 when speaking merely of prepared ox blood, it is understood that 

 1 cc. 5% ox blood was treated with 0.05 cc. amboceptor. Amounts 

 smaller than this did not suffice for complete haemolysis, and larger 

 amounts had to be avoided because then even small amounts of 

 horse serum alone would produce haemolysis. In fact according 

 to our experience the prepared blood-cells are often haemolyzed to 

 a greater or less extent by the horse serum alone when this is used in 

 rather large doses. This frequently makes it impossible to deter- 

 mine the close of horse serum, which by itself is inert but which in 



