FIXATION OF COMPLEMENT 147 



doubtful lesions. In fact, it appears that the gono- 

 coccus-fixation test enjoys greater specificity than 

 does the Wassermann reaction, since thus far we have 

 found no alien infection or condition capable of pro- 

 ducing a positive reaction. This much certainly can- 

 not be claimed for the Wassermann reaction. INIore- 

 over, there is no drug, as there is in syphilis, which is 

 capable of causing the reaction to be negative during 

 the existence of the disease. The probable explanation 

 for the greater specificity of the gonococcus comple- 

 ment-fixation test rests in the fact that with gonococcic 

 infections we employ a specific antigen — the gono- 

 coccus — while in the case of syphilis a non-specific or 

 lipotropic antigen is employed. 



The analysis of our cases further illustrates 

 another interesting feature, namely, the persistence in 

 some cases for a short time of a positive reaction, after 

 an apparent clinical cure. This has occurred so often 

 that we no longer discharge a patient cured or give 

 him a clean bill of health so long as he gives a positive 

 reaction, provided he has not been the recipient of 

 immmiotherapy. Usually a persistent positive reac- 

 tion will become negative in two or three weeks follow- 

 ing clinical cure with or without a continuation of 

 treatment. The only explanation is that it requires 

 an indefinite time for the antibodies, formed during 

 the course of infection, to disappear from the blood. 



