REAGINE AND ANTIGEN 173 



This phenomenon of Bordet and Gengou has been utilized by Wasser- 

 mann for the diagnosis of diseases where cultures are not applicable. 

 It is well recognized, however, that the body in a syphilitic serum 

 which reacts with the antigen is not an amboceptor but a lipoidophilic 

 substance, which has the property of linking complement to the 

 lipoidal antigen. The name reagine has been proposed for this lipoido- 

 philic substance. A similar substance is present in the serum of yaws 

 cases and the Wassermann reaction is just as constant in such cases as 

 in syphilis. 



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. 



Antigen. 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 specific 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. The preparation of acetone insoluble antigen is described under 

 Noguchi's method and that of syphilitic liver under the Wassermann reaction. 



Many prefer to use cholesterinized antigen. For its preparation: 



Prepare guinea-pig, beef or human heart muscle as described under acetone in- 

 soluble antigen and extract 50 grams of this finely cut up muscle with 500 c.c., 

 absolute alcohol for two weeks at 37C. Then filter and add to one-half this 

 filtrate about 7 grams of C. P. cholesterin. Keep in 37C. incubator over night and 

 then keep at a temperature of i6C. for three hours. This precipitates excess of 

 cholesterin. Filter and to the filtrate add the other one-half of the heart extract, 

 giving an antigen half saturated. 



In our laboratory we have found this antigen rather sensitive and 

 not altogether reliable and prefer to use the acetone insoluble one of 

 Noguchi. 



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

 of locomotor ataxia or general paresis, the cerebrospinal fluid. 



In using cerebrospinal fluid it is customary to employ o.i c.c., 0.2 

 c.c. and i c.c. quantities instead of the amounts given for blood-serum 

 as directed in the tests to follow. 



