BACTERICIDAL PROPERTIES OF BLOOD SERUM 165 



in the case of special complexes in which the complement may di- 

 rectly unite with free amboceptor. This, we have seen, is the basis 

 of the ISTeisser-Wechsberg conception of complement "Ablenkung" 

 or deviation, and of other ramifications of this theory. Bordet, on 

 the other hand, consistently holds that alexin or complement is at- 

 tached only by the complex antigen-sensitizer (antigen-amboceptor). 

 In the controversy which this difference aroused, an observation was 

 reported by Ehrlich and Sachs, 58 which seemed to represent, as they 

 themselves express it, an "Experimentum Crucis" proving Ehrlich' s 

 contention of the intermediary function of the amboceptor in con- 

 trast to Bordet's "sensitization" idea. The facts, as they record 

 them, are as follows: When fresh horse serum is added to guinea 

 pig corpuscles, slight hemolysis results. When inactivated ox serum 

 alone is added to such corpuscles, of course no hemolysis results. If 

 the corpuscles are, on the other hand, exposed to the action of the 

 inactive ox serum, together with fresh horse serum, very active hem- 

 olysis is brought about. Apparently the ox serum sensitizes (or 

 furnishes amboceptor to) the guinea pig corpuscles, rendering them 

 amenable to the action of the complement in the fresh horse serum. 

 In other words, inactivated ox serum can be reactivated by the addi- 

 tion of fresh horse serum. From this one would expect that if the 

 guinea pig cells were exposed to inactive ox serum, then separated 

 from the serum by centrifugalization and fresh horse serum subse- 

 quently added, hemolysis would ensue. However, this was not the 

 case. When the cells were so treated it was found that they had 

 not been sensitized, and, what is more, it could be shown that the 

 ox serum so employed had lost none of its ability to produce strong 

 hemolysis when added to another complex of cells and fresh horse 

 serum. Ehrlich and Sachs concluded that this experiment defi- 

 nitely showed the ability of the amboceptor in the ox serum to unite 

 with alexin independently. The relation to the cell occurred 

 only after the union of the amboceptor in the ox serum and the 

 complement in the horse serum had been established, and if 

 their interpretation is correct, of course, it constitutes strong 

 evidence against the general principle of "sensitization" as conceived 

 by Bordet. 



This apparent inability of the corpuscles to absorb amboceptor 

 independently out of the inactivated ox serum, and the fact that 

 hemolysis results only if the corpuscles, ox serum, and fresh horse 

 serum are all simultaneously present, are extraordinary and not at 

 all in keeping with the preceding work of Ehrlich and Morgenroth, 

 and indeed with experience of these phenomena in general. It is log- 

 ical therefore to examine more closely the peculiar conditions main- 

 tained in these experiments before applying the reasoning deduced 

 from obviously different phenomena to their explanation. 



58 Ehrlich and Sachs. Berl. Win. Woch., No. 21, 1902. 



