502 A MANUAL OF BACTERIOLOGY 



body, and the complex then takes up complement ; this is demon- 

 strated by the use of a haemolytic system (p. 184). 



As a matter of fact, however, the Wassermann reaction, as it 

 is preferably termed, is apparently not a true antigen reaction, for 

 substances may be used as antigen which are soluble in alcohol, 

 and various non-specific bodies may be similarly employed. More- 

 over, the nature of the substances which act as amboceptor and 

 fix the complement is uncertain ; some regard them as globulins, 

 others as lipoids, and while Wassermann considered them to be 

 specific anti-bodies, others believe them to be derived from a peculiar 

 degeneration or breaking down of the tissues in syphilis. Again, 

 the reaction is not confined to syphilis : it may also be obtained 

 with the syphilitic " antigen " in malaria, trypanosomiasis, yaws, 

 leprosy, and the early stage of scarlatina. 



In the original method a fresh salt-solution extract of the liver 

 of a syphilitic fetus was used as the " antigen." Levaditi employed 

 a similar extract of the dried and powdered liver. The test-sub- 

 stance was the blood -serum inactivated by heating to 56 C. for 

 half an hour or cerebro -spinal fluid of the patient. The complement 

 was guinea-pig serum, and the haemolytic system sheep's corpuscles, 

 and a serum haemolytic for these corpuscles. 



Many modifications of this method have since been introduced 

 both as regards the reagents employed antigen, complement, and 

 haemolytic system and the manner of carrying out the test. These 

 may now be briefly considered and the manner of carrying out the 

 test described. 



(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 extrac- 

 tion 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 Treponema pallidum obtained 



by Noguchi's method. 



Probably the most widely employed antigen at the present day 

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



1 Heart muscle is peculiar in that it contains a large amount of lipoid 

 substances. 



