COMPLEMENi' FiXATION fX SYPHILIS 435 



tive reactions were re-checked. The incidence of positive tests in 

 these students, all of whom were nonsyphilitie, as judged by 

 history and physical examination, was approximately 1:1,125. 

 As Eagle says, at first sight, this incidence appears disturbingly 

 high. However, when the results are analyzed in the light of the 

 incidence of known .syphilis in the respective campuses he found a 

 rather liigh correlation between the number of known cases of 

 syphilis and the number of apparent false positive reactors. 



When these facts are taken into consideration a revised estimate 

 would suggest that the number of biologic false positives was not 

 over 1 in 4,000 students. It should be remembered that these data 

 have been obtained only for the age group of college students. Our 

 results (Sherwood, Bond and Canuteson, 1941) on 1,018 stu- 

 dents conformed quite closely to the results obtained for the whole 

 group. 



Kahn (1941) i-oports tiiat the noi-mal biologic reagin can be 

 differentiated from .syphilitic reagin by a new flocculation tech- 

 nique which he calls the V erification test. He finds that animal and 

 human sera that give false positive reaction will sliow .stronger reac- 

 tions at 1° C. than at 37° C. whereas syphilitic sera give weaker 

 or negative reaction.s at 1° C. and stronger reactions at 37° C. 

 This test will be described briefly in the next chapter. 



Mechanism of the Wassermann Reaction, — The mechanism of 

 the Wassermann reaction is discussed extensively by WelLs (1929), 

 Zinsser (1931), lOagle (1929, 1930, 1931) and others. The exact 

 origin and nature of syphilitic reagin is at present unknown. 

 While it has the properties of an antibody, it has been generally 

 regarded as not specific for Treponema pallidum as Wa.s.sermann 

 originally thought, but consistently sensitizes certain lipoids when 

 they are properly dispersed in saline. Eagle and Hogan (1940), 

 however, regard the reagin as specific for a lipoid common to both 

 animal tissue and Treponema pallidum. According to Wells (1929) 

 Sachs suggests that perhaps infection with Treponema pallidum 

 cau.ses the liberation or formation in the l)ody of li})o-proteins for 

 which the tissues produce an antibody which we call reagin. He 

 conceives of the lipoid or liapten portion as present in the tissues 

 of many animals and that reagin will sensitize such a hapten anti- 

 gen in vitro just as the haptens previously discussed will react 

 in vitro with homologous immune serum. 



