216 



COLLECTED STUDIES IX IMMUNITY. 



plementoid still takes place. In this way we sought to find an approx- 

 imate criterion for relative affinity of the complementoid. From 

 the power to be reactivated possessed by the guinea-pig blood-cells 

 previously treated at different temperatures with inactive dog serum 

 it was seen that even at 3 C. a moderate binding of complementoids 

 takes place, and that complete blocking phenomena can already be 

 obtained at 8 C., as is seen in the following experiment: 



TABLE VI. 



Nevertheless we believe that even in this case a certain, though 

 slight, decrease in the affinity has occurred in the complementoid 

 formation. At least the fact speaks in favor of this, that with the 

 simultaneous addition of inactive dog serurn (i.e., amboceptor + com- 

 plementoid) and active guinea-pig serum solution of the guinea-pig 

 blood occurs. Under these circumstances, in which the amboceptor 

 has both complement and complementoid to choose from, the former 

 is preferred. When, then, we find that it is possible by previous treat- 

 ment with complementoid to block the complementophile group of 

 the amboceptor for the complement subsequently added, we shall 

 explain this most readily by assuming that after the complementoid 

 has been anchored, the union becomes firmer. Analogous phenomena 

 are common in immunity. Thus Donitz * has shown that the union 



unusual tone of this attack surely offers sufficient provocation, merely expressing 

 my astonishment at the fact that Gruber's exposition disregards the most 

 important and explanatory point, namely, as Morgenroth and I have emphasized, 

 that in the change into complementoids, the complements must usually suffer a 

 decrease in their affinity, for only in this way can the absence of all disturbing inter- 

 ference on the part of these complementoids in test-tube experiments be explained. 

 If, however, Gruber assumes a complete destruction of the complements by 

 inactivation how does he explain the fact easily verified by every one, namely, 

 the production of anticomplements by injection into the organism of serum 

 which has been heated? Surely a mere wish floating around in the serum 

 cannot suffice to produce anticomplements. EHRLICH. 



1 Donitz, Uber die Grenzen der Wirksamkeit des Diphtherieheilserums. 

 Arch, internat. de Pharmacodynam., Vol. V, 1899. 



