628 



COLLECTED STUDIES IN IMMUNITY. 



TABLE VI. 



treatment of the native serum at 37. This is all the more notice- 

 able because in the above table a slight reduction of hsemolytic 

 power is shown as a result of digestion at 0. This reduction is 

 probably due to a slight loss of supernatant fluid in decanting the 

 centrifugates. The result of the experiment is absolutely at var- 

 iance with the colloid theory. Assuming that the horse serum 

 acts both as amboceptor and complement, while the ox serum, 

 in accordance with the view of Bordet and Gay, furnishes a "col- 

 loid " which takes part in the haemolysis, it follows that successive 

 treatment at and 37 would effect a greater reduction of the 

 active principle than a single treatment at 37. The result, on 

 the other hand, harmonizes perfectly with the view expressed 

 by Ehrlich and Sachs, and could, in fact, have been foretold on the 

 basis of that conception. The horse serum furnishes only the 

 complement. By treatment at a portion of the amboceptor is 

 removed, so that the serum thus becomes rich in complement but 

 poor in amboceptor. On digesting such a serum once more with 

 guinea-pig blood, at 37, a small amount of complement is removed 

 through the intervention of what amboceptor still remains. The 

 loss of complement thus sustained is bound to be less than that 

 observed when native serum (which is rich in amboceptor) is digested 

 with guinea-pig blood. Our experimental analysis therefore 

 shows that the interpretation offered by Bordet and Gay cannot 

 be harmonized with the facts. In fact our study furnishes addi- 

 tional confirmation for the view that in the case under discussion 

 the ox serum acts as an amboceptor with the horse serum as com- 

 plement. 



