610 A MANUAL OF BACTERIOLOGY 



The essentials for carrying out the Wassermann reaction are 

 (1) antigen, (2) complement, (3) hsemolytic system, and (4) the 

 fluid to be tested. 



Many modifications of the reagents used and of the method 

 of carrying out the test have been introduced, and a brief survey 

 of some of these may be given. 



(a) Antigen. The various substances which have been used as 

 antigen include : 



1. A watery or alcoholic extract of syphilitic fetal liver. 



2. Alcoholic extract of normal liver or heart-muscle 1 (human, 

 ox, sheep or guinea-pig), with or without previous extraction 

 with acetone. 



3. Alcoholic extract of normal heart-muscle with the addition 

 of cholesterin. 



4. Various artificial mixtures, e.g. lecithin and cholesterin, 

 sodium glycocholate or taurocholate. 



5. Extracts of pure cultures of the Spironema pallidum obtained 

 by Noguchi's method. 



Probably the most widely employed antigen at the present 

 day is number (3), the so-called " Sachs antigen." 



(b) The Complement. Fresh guinea-pig serum is generally em- 

 ployed as complement, the patient's serum being inactivated to 

 destroy its complement. In some methods the patient's serum 

 is not inactivated and the complement present in it is that used. 

 Fresh rabbit or human serum has also been used as complement. 



If guinea-pig serum be used, its complement content can be esti- 

 mated and the same amount of complement may therefore always 

 be employed in the test. 



(c) The Hcemolytic System. This may be serum hsemolytic 

 for ox, sheep, human or other red blood corpuscles, with the 

 homologous corpuscles. The hsemolytic serum should have 

 a fairly high titre and the corpuscles be fresh and well washed 

 with saline. 



Serum hsemolytic for sheep's corpuscles with sheep's corpuscles 

 is the hsemolytic system usually employed. The hsemolytic 

 serum is inactivated. 



As human serum in low dilution is generally (75 per cent.) 

 hsemolytic for sheep's corpuscles, the patient's serum itse7f 



1 Heart muscle is peculiar in that it contains a high content of lipoid 

 substances. 



