598 



COLLECTED STUDIES IN IMMUNITY. 



the 1 cc. of sensitized blood-cells, had, of course, dissolved. The 

 degree of solution which the other half had undergone, varied 

 with the length of time after which the complement was added, 

 and is shown in the accompanying table: 



On subsequently adding a further 0.2 cc. guinea-pig serum to 

 tubes 1-4, and placing them in the water-bath, complete solution 

 was produced. 



It is not difficult to explain this phenomenon. On adding 

 complement to mixtures of sensitized and fresh blood-cells, the 

 complement is rapidly bound by the anchored amboceptors. We 

 know from earlier experiments that these have an increased affinity 

 for the complement. 1 If the amount of complement is relatively 

 small, while that of the anchored amboceptors is large, it is obvious 

 that only part of the amboceptors will be occupied by complement. 

 The anchored amboceptors which have bound complement are 

 evidently no longer able to let go of their receptor. This fact 

 shows that the anchoring of the complementophile group of the 

 amboceptor produces an increase in the binding power of the 

 cytophile group. The anchored amboceptors which are uncom- 

 bined with complement, naturally retain their freedom of move- 

 ment, and are thus enabled to pass over to the freshly added blood- 

 cells. This is demonstrated by the occurrence of haemolysis on 

 the further addition of complement. 



We believe that these experiments constitute an important 

 addition to our knowledge of the relations existing among ambo- 

 ceptor, receptor, and complement. From a well-known experiment 

 made by Bordet, 2 we know that after haemolysis has begun, ambo- 

 ceptor and complement remain permanently combined. Bordet 



1 Ehrlich and Morgenroth, Berliner klin. Wochenschr., No. 1, 1899. This 

 volume, page 1. 



2 Bordet, Annales Pasteur, No. 5, 1901. 



