THE WASSERMANN REACTION IN SYPHILIS 405 



explanation of its mechanism is still lacking, as the large number of 

 theories advanced tend to show. 



While lipoidal extracts, as well as normal and luetic serums, may sepa- 

 rately absorb or fix small amounts of complement, a mixture of a suitable 

 extract and syphilitic serum is capable of fixing large amounts of comple- 

 ment, and this constitutes the main principle and all that is definitely 

 known of the syphilitic reaction. 



The serum of a syphilitic is characterized, therefore, by the presence 

 of this (lipodotropic, antibody-like substance,) which has a great affinity 

 for lipoids and in mixture with them will cause the absorption or fixation 

 of complement to a well-marked degree. Instead of being an example 

 of complement fixation in a mixture of specific antigen with specific 

 antibody, as originally believed, it is technically a non-specific reaction, 

 but practically it is highly specific^since this peculiar antibody is found 

 in largest amount and most constantly in syphilis, and to a lesser extent 

 in practically only two other diseases, namely, leprosy and fraroJiesia.J 

 In countries and districts where these diseases are infrequent or unknown 

 with proper technic the reaction for syphilis is highly specific. 



As will be shown further on, the presence of this lipodotropic sub- 

 stance is dependent upon the activities of the Treponema pallidum, 

 and when repeated tests continue to show its presence, there is every 

 reason to believe that a cure has not been effected, but that the patient 

 still harbors the living parasite. 



Citron has advanced the hypothesis that the antibody-producing 

 antigen is a toxolipoid, which would explain the fact that while pure 

 lipoids, such as lecithin, cannot stimulate antibodies (Bruck), as the 

 toxolipoid does, they can, nevertheless, react with the lipodotropic 

 antibodies in vitro, with fixation or absorption of complement. As 

 Sachs and Altman point out, an equally tenable theory would be that in 

 syphilis the tissues undergo such alterations that they can produce anti- 

 bodies to the lipoid substances as may be contained in the spirochetes 

 themselves. 



While the production of this lipodotropic antibody is still unex- 

 plained, the fact remains, nevertheless, that it forms the basis of the 

 biologic syphilitic reaction, and in a mixture with a suitable lipoid is 

 capable of absorbing or inactivating complement to a marked degree. 

 Whether or not it is a true antibody in the sense that it is inimical to the 

 spirochete is doubtful ; by many it is regarded as a secondary product of 

 cellular activity, and has been called syphilis "reagin." 



Since similar "reagins" are to be found in other infections, notably 



