COMPLEMENT FIXATION 147 



supernatant fluid. This phenomenon of Bordet and Gengou has been 

 utilized by Wassermann for the diagnosis of diseases where cultures are 

 not applicable. It is in the diagnosis of syphilis that it is best known. 

 It having until recently been impossible to obtain cultures of Treponema 

 pallidum, we use an emulsion of the liver of a syphilitic foetus, which 

 has been filtered so as to be clear, instead of a culture. The syphilitic 

 liver, as can be observed by staining according to Levaditi's method, is 

 packed with spirochaetes. 



While Noguchi has recently obtained pure cultures of the organism of syphilis 

 yet the antigen prepared from such cultures was not found as satisfactory by Craig 

 and Nichols as that from the liver of a syphilitic foetus, cases of syphilis which showed 

 strongly positive tests with ordinary antigen not giving a positive test with the spe- 

 cific antigen. 



It has now been found that lecithin or, preferably, emulsions of various normal 

 organs may be substituted as antigen for the syphilitic liver, the antigenic power 

 being due to lipoids. Aqueous extracts contain in addition to lipoids, substances 

 which render the antigen unstable alcoholic extracts are more stable and contain 

 less anticomplement. 



For the immune bodies we take the serum of the patient, or if a case of locomotor 

 ataxia or general paresis, the cerebrospinal fluid. 



EMERY'S TECHNIC FOR THE WASSERMANN TEST. 



Owing to technical difficulties with the method of making and 

 employing the antigen and amboceptor features of the original Emery 

 test, I have retained the principle of the test but substituted the 

 reagents prepared in exact accordance with Noguchi's directions. 



Briefly stated, the principle of Emery's test consists in the employ- 

 ment of fresh human serum for supplying complement and the pri- 

 mary incubating of the hemolytic system (human red cells and rabbit 

 serum immune to human red cells) at the same time as the incubation 

 of the antigen and serum but in separate tubes. Then in the second 

 period of incubation to add these " sensitized" cells to the serum 

 antigen combination. 



In Noguchi's method all reagents are incubated together in the 

 first period with the exception of the amboceptor paper (dried serum 

 of rabbit immune to human red cells), which is not added until the 

 period of incubation for complement binding is completed and the 

 second incubation commenced. Time is saved in the Emery tech- 

 nic, inasmuch as the red cells are already sensitized by the hemo- 



