578 COLLECTED STUDIES IN IMMUNITY. 



In view of the extraordinary success which physical chemistry 

 has scored, it is readily understood how tempting it was for so emi- 

 nent a representative of this science as Arrhenius to apply its princi- 

 ples to the new field of immunity. I have always emphasized the 

 chemical nature of the reaction, and am glad therefore that the 

 attempt to apply these principles has been made. It has demon- 

 strated anew that the phenomena of animate nature represent merely 

 the resultants of infinitely complex and variable actions, and that 

 they differ herein from the exact sciences, whose problems can be- 

 treated mathematically. The formulas devised by Arrhenius and 

 Madsen for the reaction of toxins and antitoxins explain absolutely 

 nothing. Even in particularly favorable cases they can merely 

 represent certain experimental results in the form of interpolation 

 formulas. Neither do I believe that the phenomena observed in 

 toxins and antitoxins bear any relation to the processes of colloid 

 chemistry. The attempt which has been made to interpret the 

 immunity reaction from the standpoint of colloid chemistry, a sub- 

 ject itself more or less obscure, is based on purely external analogies. 

 I see absolutely no advantage in such a method, and I have grave 

 fears that it will result in checking further progress along this line. 

 Structural chemistry, on the other hand, has not only served to 

 explain all the phenomena in immunity studies, but has also proved 

 a valuable guide in indicating the lines along which further progress 

 might be made. The limitations of colloid chemistry have already 

 manifested themselves, and enthusiastic advocates of this science 

 have been compelled to assume the existence of specific atomic 

 groupings in accordance with my views. I therefore see no reason 

 for abandoning the views expressed in my receptor theory, a theory 

 in complete accord with the principles of synthetic chemistry. My 

 decision finds additional support in the fact that the studies in 

 immunity are constantly bringing to light new observations best 

 harmonized with the views of structural chemistry. Thus I may 

 remind the reader that Morgenroth has recently very cleverly proved 

 the postulate that the components of the neutral toxin-antitoxin 

 combination can be restored. This author succeeded in completely 

 recovering the two components of a neutral mixture of cobra venom 



(Berl. klin. Wochenschr. No. 8, 1905) have been effectually answered by van 

 Calcar by means of some additional experiments, and by the demonstration 

 that the membranes employed by Homer were unsuitable (Berl. klin. Woch. 

 No. 43, 1905). 



