54 IMMUNE SERA. 



and the leucocytes. Gruber as well as Schatten- 

 froh are ready to believe the leucocytes to be the 

 source of an alexm, but claim that this is different 

 from that found in serum. I myself believe that 

 the leucocytes are a source of complements (alexins) ; 

 for I succeeded in producing anti-complement by 

 means of injections of pure leucocytes which had 

 been washed free from all traces of serum, and 

 which had been obtained by injections of aleu- 

 ronat. Because of the plurality of the complements, 

 I have expressed the view that the leucocytes are 

 probably one source, but not the only one, for the 

 complements of the serum. Landsteiner and 

 Donath have confirmed my views experimentally. 

 They succeeded in producing anti-complement by 

 the injection not only of leucocytes, but of other 

 animal cells. Furthermore, the experiments of 

 Ehrlich and Morgenroth already mentioned, in 

 which the complements disappeared after the de- 

 struction of the liver function, show that the liver 

 cells are concerned in the formation of complements. 

 Structure of Complements Haptophore and Zymo- 

 toxic Groups Complementoids. The structure of 

 the complement has been studied particularly by 

 Ehrlich and Morgenroth, and by P. Miiller. We 

 have seen that the complements lose their power 

 when heated to 55 C. If, however, we inject ani- 

 mals with a normal serum that has previously been 

 heated to 55 C., we shall still excite in these ani- 

 mals the production of anti-complements. This 



