STUDIES ON ILEMOLYSINS. 81 



the complements or merely changed them into inactive derivatives, 

 complementoids. 1 



In order to be certain of the destruction of the zymotoxic group, 

 we heated the sera for fifty minutes to 60 C., a procedure, as shown 

 by numerous subsequent examinations, which absolutely destroys 

 every trace of complement action in the sera so treated. 



By treating animals with the sera thus prepared, it is actually 

 very easy to obtain anticomplements. We injected rabbits, guinea- 

 pigs, and dogs with inactive goat serum, and goats and numerous 

 rabbits with inactive horse serum. A parallel series of animals 

 was treated with active serum. The anticomplement action of 

 the serum from the animals treated with complementoids proved 

 fully as strong and often stronger than that of the control animals 

 treated with active serum. By means of the procedure described 

 in detail in our Fourth Communication it was readily shown that 

 these were really anticomplements. 



The injection of the heated serum, therefore, possesses the same 

 value as that of the unchanged serum. 2 Since, however, accord- 

 ing to our view it is the haptophore group which causes the immu- 

 nity reaction, it follows that inactivation of the complement has de- 

 stroyed only the zymotoxic group, leaving the haptophore group intact. 



The important question now arises as to how the presence of 

 complementoids influences the activation of the immune body; 

 for whenever a serum is inactivated by heating a formation of com- 

 plementoid ensues, and it is well known that such a mixture of immune 

 body and complement is reactivated without any trouble by the 

 addition of complement. It seems therefore as though the presence 

 of the complementoid does not hinder the union of immune body 

 and complement. 



On this point we have made special experiments by alternately 



1 At about the same time, exactly similar considerations led Paul Miiller 

 (Centralblatt }. Bacteriologie, Vol. 29, No. 5) to attempt the production of 

 anticomplement by the injection of serum which had been heated. In his 

 case, however (immunization with chicken blood), anti-interbody was prin- 

 cipally developed, while anticomplement could not positively be demon- 

 strated. It is possible that this negative result indicates that not all the com- 

 plements of the different animal species are able to undergo this metamorphosis 

 into complementoid. 



2 We should like to mention that in addition to this, in the case of the goat 

 treated with inactive horse serum, we observed the development of a powerful 

 coagulin. 



