188 



COLLECTED STUDIES IN IMMUNITY. 



We now repeated the experiment of separation in the cold by 

 allowing the fluid which was decanted from the guinea-pig blood-cells 

 after these had been treated with active dog serum at C., to act 

 on guinea-pig blood sediments previously mixed with dog serum. 

 Our results were in accord with the above and led to a clear under- 

 standing of our previous negative findings. See Table V. 



TABLE V. 



ABSORPTION OP DOG SERUM BY GUINEA-PIG BLOOD AT C. 

 (0.075 cc, dog serum just completely dissolves 1 cc. 5% guinea-pig blood.) 



In this case, therefore, we have demonstrated a thermolability 

 of the amboceptor 1 which shows itself especially in the activa- 

 ting experiment with guinea-pig complement, but also in that with 

 its own dog (complement). Only through this thorough analysis 

 was it possible to furnish for Buchner's third negative case also 

 positive proof of the complex constitution of normal hsemolysins. 



After having determined that certain amboceptors will only 



1 It is therefore not at all permissible to define the two components of the 

 haemolysin, as Gruber would do (Discussion of Gruber's Address, Wiener Klin. 

 Wochensch. 1901, No. 50), only according to the temperature, and to say that at 

 a certain degree of heat the amboceptor remains intact while the complement 

 does not. As long ago as their second communication Ehrlich and Morgenroth 

 described a thermostable complement of goat serum which remained intact at 

 56 C. ; and according to our experiences here described a general definition of 

 amboceptors as bodies which withstand heating to 55 C. is absolutely impos- 

 sible. The influence of temperature on amboceptor and complement varies 

 from case to case. Hence that these two factors act together in haemolysis we 

 know only from this, that two substances, in themselves not capable of causing 

 solution, when combined, effect hcemolysis; and that one of these substances (the 

 complement) can never alone be bound by the blood-cells but always only through 

 the intervention of the other (the amboceptor). 



