302 COLLECTED STUDIES IN IMMUNITY. 



snake venom. This antihaemolysin is thermolabile, being destroyed 

 by temperatures over 56 C. The other (the activating) constituent 

 of the serum on the contrary is thermostable, since it does not lose 

 its activity even by heating to 80 C. Calmette therefore assumes 

 that the alexin (our complement) takes no part in the activation, but 

 that a particularly thermostable "substance sensibilatrice" is con- 

 tained in the serum besides the thermolabile antihoemolysin. By the 

 term "substance sensibilatrice/ 7 as used in French terminology, is 

 meant the body which we term "amboceptor." The amboceptor 

 capable of being anchored is supposed to render the red blood-cells 

 sensitive to the attack of the alexin (complement). It is hard to 

 see just how Calmette conceives this entire process. As we already 

 know from the researches of Flexner and Noguchi snake venom is 

 capable of being anchored, and from all of its properties is therefore 

 surely a substance sensibilatrice (amboceptor). If then the substance 

 supposed by Calmette were also a sensitizer, we should have before 

 us something absolutely unique, namely, the combined action of two 

 sensitizers. Unfortunately Calmette has undertaken no combining 

 experiments and therefore has furnished no proof for his view. Our 

 own experiments, however, speak against this assumption. 



In our opinion the main reasons which led Calmette to conclude 

 that complements play no role in the haemolysis by means of cobra 

 venom are : 



1. That he overlooked the endocomplements. 



2. That he employed too schematic a manner of activation, namely, 

 usually only at 62 C. 



We have convinced ourselves that in suitable cases (see Table 

 VII, case IV) a blood serum, e.g. ox serum, when fresh, dissolves 

 the red blood-cells. If this is inactivated by heating to 56 C., the 

 action will be found to be completely inhibited, or almost so. This 

 same serum, however, when heated to 65 C. or higher is again able 

 to effect haemolysis. The serum heated in this manner possesses a 

 stronger solvent power than the fresh serum, for even fractional 

 parts of the complete solvent dose of fresh serum suffice to cause 

 full solution (see Table VI). 



This experiment was repeated many times and proves that in 

 this case two entirely different kinds of activations occur, namely, 



1. Activation by means of complements. 



2. Activation by means of substances which become manifest only- 

 through heating. 



