56 



Scientific Proceedings (36). 



This non-specific fixation of complement can be avoided by 

 inactivating the sera before testing. From the above finding it 

 follows that no complement fixation test, with a view of obtaini?ig 

 a specific reaction, should be made with unheated serum. On the 

 other hand, the Wassermaiui reaction can be carried out with active 

 human sera when the antigen does not contain those substances which 

 are found to give a non-specific reaction with the active sera. 



I usually use in my system of the Wassermann reaction active 

 sera and pure lipoids free from proteins and have never obtained 

 the so-called non-specific reaction. It is not possible, however, to 

 obtain reliable results if one uses aqueous or alcoholic extracts of 

 liver as antigen, because these extracts contain the disturbing pro- 

 teins already referred to. When one intends to use aqueous or 

 alcoholic extracts as antigen, the patient's serum should be inac- 

 tivated before using. In a recent article by Swift, I noticed that 

 he obtained positive reactions in certain non-syphilitic cases by 

 employing my method and he states that this can be avoided by 

 using inactivated sera. I would like to call attention to the fact 

 that he used alcoholic extracts and not pure lipoids (acetone- 

 insoluble fractions as recommended by me) in the former of which 

 there exist large quantities of proteins capable of producing false 

 fixation with the active sera. Hence his results. 



For the sake of clarity, I propose to call the non-specific reac- 

 tion caused by active serum and these proteins proteotropic fixation, 

 and the Wassermann reaction caused by syphilitic and leprous 

 sera in the presence of lipoids lipotropic. 



No parallelism is found to exist between the proteotropic and 

 the lipotropic properties of a given specimen of serum. Inactiva- 

 tion removes the proteotropic property almost entirely, while it 

 only reduces the lipotropic titre to about one-fourth of the original 

 strength. 



