A GENERAL REVIEW OF THE RECENT WORK IN IMMUNITY. 583 



apparatus is concerned. In a way, therefore, the amboceptor bears 

 the stamp of the animal species from which it is derived. In this 

 connection I have already expressed my views in the article entitled 

 " The Mechanism of the Amboceptor Action and its Teleological Sig- 

 nificance " (Koch Festschrift, 1903): "In general, the specific ambo- 

 ceptors possess a uniform structure in their complementophile por- 

 tions, whereas they differ to a high degree in their cytophile groups, 

 whose physiological function is the absorption of foodstuffs." 



The studies of antiamboceptors have demonstrated that this con- 

 ception is correct. We see, therefore, that the specificity of the com- 

 plementophile group of the amboceptor, a specificity based on the 

 animal species, at once leads to a difference in the amboceptors 

 obtained from different species by means of the same immunizing 

 material. In our Sixth Communication on Haemolysins, Morgenroth 

 and I published certain experiments showing that by means of an 

 antiamboceptor we had been able to demonstrate the diversity of 

 the amboceptors produced in different animal species by injections 

 of ox-blood. This statement still holds good, and its direct conse- 

 quence demands that in the practical application of bactericidal sera, 

 we should mix immune sera derived from different animals. 



In view of Bordet's observation, however, we shall have to revise 

 our interpretation in so far as the site of this differentiation is con- 

 cerned; the difference is in the complementophile group instead of 

 in the cytophile group. On the other hand, we must abandon the 

 differentiation of partial amboceptors in one and the same serum by 

 means of antiamboceptors, a differentiation which we proposed in 

 the study on hsemolysins. It must not be thought, however, that 

 the pluralistic conception of the amboceptor apparatus is thereby 

 overthrown. This conception is supported by so many arguments" 

 of a different kind that the existence of partial amboceptors can be 

 classed as one of the demonstrated facts in immunity. I may remind 

 the reader that by means of mutual elective absorption it is possible 

 to differentiate the strictly specific portion of an immune serum 

 from the non-specific components which give rise to the group reac- 

 tions. By this means the presence of different amboceptor fractions 

 could be demonstrated in the same immune serum. The observa- 

 tions made by Morgenroth and myself on isolysins also speak strongly 

 -in favor of a multiplicity of amboceptors. In these the possible 

 presence of antibodies acting on the complementophile portion of the 

 amboceptor is absolutely excluded. Finally, if we glance at the con- 



