72 COLLECTED STUDIES IN IMMUNITY. 



served to demonstrate the complete harmony of the theory with the 

 facts on this subject. Furthermore after overcoming considerable 

 experimental difficulties we succeeded in demonstrating the same 

 behavior for the haemolysins of normal serum and thus brought these 

 also under the laws of the side-chain theory. Reexaminations from 

 various directions confirmed the correctness of our fundamental 

 experiments and we may say that at present the majority of workers 

 in this field, partly as a result of their own experiments, have accepted 

 our views and regard the side-chain theory as a justified hypothesis 

 which best explains most of the phenomena thus far observed in the 

 subject of immunity. Since this in part concerns processes in 

 which the animal organism acts with all its highly complicated con- 

 ditions, it is no wonder that now and then a fact has appeared in 

 the course of the investigations which at first seemed to be irrecon- 

 cilable with the theory. The latter, however, is in no way injured 

 thereby, for the solution of such apparent contradictions results 

 in a deeper understanding of the subject and makes for progress. 

 An instructive example of this was recently afforded in physical 

 chemistry. As is well know r n, several at first inexplicable contra- 

 dictions to van't Hoff's theory of solutions, resulting from certain 

 deviations in osmotic tension, found their explanation in the theory 

 of electrolytic dissociation of Arrhenius, and this theory served to 

 again obtain general acceptance for the theory of solutions itself. 

 We have therefore endeavored to analyze carefully the objections 

 urged against our views by high authorities. 



The objection raised by Metchnikoff l against the specific formation 

 of the toxins was based on the fact that even castrated rabbits yield 

 an antispermotoxin. In a recent study 2 from the laboratory of 

 Metchnikoff, this objection is withdrawn. It was found that in this 

 antispermotoxin an anticomplement is principally concerned and 

 not an anti-immune body, for it was produced even by treatment 

 with normal serum. 3 It is therefore especially gratifying that Metch- 

 nikoff also has recently accepted our view that the complement 

 is anchored to the immune body by means of the latter's complement- 

 ophile group. 



An important objection made by Bordet 4 based on some extremely 



1 Annales de 1'Institut Pasteur, 1900, No. 1. 



2 Ibid., No. 9. 



3 See von Dungern, page 47. 



4 Annales de PInstitut Pasteur, 1900, No. 5. 



