230 CHEMISTRY OF THE IMMUNITY REACTIONS 



sera,^° and for the identification of bacteria, and was found to be ex- 

 quisitely delicate, detecting most minute amounts of antigens with 

 the sharpest specificity limits of any of the immunity reactions. On 

 account of the delicacy of this reaction it can be used to determine 

 the presence in tissues of specific organisms which cannot be culti- 

 vated; thus, it has been possible to demonstrate the existence of a 

 specific scarlatinal virus^^ in the tissues during this disease, although 

 the actual organism cannot be isolated. This fact led Wassermann 

 to use extracts of the livers of congenital sj'-philitic fetuses, which 

 contain great quantities of spirochetes, as an antigen for complement 

 fixation reactions, whereby it should be possible to determine in a 

 given serum the presence of specific amboceptors for the virus of 

 syphilis, such amboceptors being present in persons infected with 

 syphilis as a result of the reaction to the infection. As originally in- 

 troduced, then, the Wassermann reaction was supposed to be simply 

 a specific reaction between syphilitic antigen, specific syphilitic am- 

 boceptors, and non-specific complement. It was soon learned, how- 

 ever, that the reaction as it occurred in syphihs was decidedly 

 different from the original complement fixation reaction of Bordet 

 and Gengou, for it was found possible to substitute in the reaction for 

 extracts of tissues containing syphilitic virus (spirochetes), the most 

 varied sorts of tissue extracts, coming from tissues certainly free 

 from spirochetes (e. g., ox heart). Noguchi and Bronfenbrcnncr^^ 

 summarize the present state of the matter in these words: "We know 

 merely this: that complement in the presence of syphilitic antigen 

 may be rendered inactive by one or more substances in the body 

 fluids of a syphilitic or parasyphilitic patient." 



Extended investigation of these non-specific antigens which give 

 specific complement fixation with S3^philitic sera, has shown them to 

 be related to the lipoids, especially the lecithins, as indicated by the 

 fact that the most efficient antigens contain the accton-insolublo frac- 

 tion of the tissue lipoids. The antigenic value of this fraction of 

 different liver extracts varies nearly directly with its power to com- 

 bine with iodin*^ (Noguchi and Bronfenbrenncr), which indicates 

 that the unsaturated fatty acids arc important in the reaction.^'' 



'S" Accoi-fling to Gay (Univ. of Calif. Publ., Piithol., 1911 (2), 1, full discus- 

 sion) conipleinent fixation i.s produced by an antincn-antihody I'oinjjlex distinct 

 from precipitinof^en-precipitin, but Dean (Zeit. f. Ininumitat., 1912 (13), 81) be- 

 lieves that they represent two phases or stages of the same reaction. Thiele and 

 Embleton (Zeit. luuaunitat., 1913 (10), 430) consider tliat in syphilis it is not 

 a specific antibody, but an anti-complementary substance which arises from the 

 disintegrating tissiies. 



^' Koesslerand Koessler, Jour. Infec. Dis., 1912 (9), 3GG. 



" Jour. Exp. Med., 1911 (13), 43. 



'^ Not corroborated by Hrowning, Cruickshank and (iilmour.'''' 



^* An interesting observation made l)y Noguchi and Hrt)nfenbrenner, is that ex- 

 tracts from fatty livers are alnut.st devoid of antigenic projuMties; but So (Cent. f. 

 Bakt., 1912 (03). 43.S) found that the extract from fatty hearts of guinea-pigs 

 was more active than from normal hearts. 



