WASSERMANN AND OTHER COMPLEMENT FIXATION TESTS 247 



When the tubes containing one unit of complement show no hemolysis the 

 reaction is positive, indicative of syphilis; in this case the tubes containing two 

 units of complement may show complete, incomplete or no hemolysis, dependent 

 upon whether the o.i cc. of syphilitic serum contained just enough amboceptors 

 to fix one unit of complement or more than that amount. 



Occasionally, at the end of the second hour of incubation, half or more of the 

 red cells will remain unhemolized in the tube containing one unit of complement. 

 If incubated longer or allowed to stand at room temperature for 6 or 8 hours 

 hemolysis may eventually be complete or it may remain incomplete. A 

 serum which gives this atypical reaction may be syphilitic or it may not. Such 

 a reaction must be reported doubtful. 



PREPARATION OF ANTIGEN 



Originally antigen for the Wassermann test was made by placing a finely 

 hashed liver of a syphilitic fetus in a dark bottle with five times its volume 

 of normal salt solution and shaking continuously for 48 hours. The contents 

 of the bottle were then filtered through fine gauze and 0.25 per cent, of tricresol 

 added. Such extracts are not as commonly employed at present because of the 

 discovery that alcoholic extracts can be more easily made, are more stable and 

 in the majority of cases are equally as good. Salt solution extracts frequently 

 deteriorate so as to be useless in i or 2 months, some remain stable for years. 

 It would seem from the known facts in regard to bacterial antigens in general 

 that the salt solution extract of syphilitic tissue is the only extract that contains 

 treponema pallidum antigen. Be that as it may, large series of comparative 

 tests show that its only superiority is in some of the cases giving a doubtful 

 reaction with other extracts. 



Alcoholic extracts are the most commonly employed at present and are most 

 easily made. The method of preparation is the same, whether syphilitic fetal 

 liver, fetal heart, guinea-pig liver and heart or ox heart is used. The tissue is 

 passed through a meat grinder or cut into as small pieces as possible with scis- 

 sors, fibrous tissue removed and discarded, the rest ground to a pulp in a mortar 

 and put in a ground-glass-stoppered bottle; 10 times its volume of absolute 

 alcohol is added, the bottle hermetically sealed and shaken for 15 minutes. It is 

 then placed in an incubator at 37C. for Todays, being shaken for 5 or 10 minutes 

 every day. At the end of this time it is filtered through paper until perfectly 

 clear and free of suspended particles and stored in a dark closet. Immediately 

 before use it is diluted with salt solution, but as the salt solution dilution tends 

 to deteriorate in several days or weeks, it is not good practice to dilute the alco- 

 holic extract except as required. 



Ether soluble acetone insoluble extracts, usually made from ox heart, have 

 been very much lauded by some but in practice show little if any superiority 

 over alcoholic extracts. The technique for preparing this antigen and its sup- 

 posed superiority has been fully discussed by Noguchi (Proc. Soc. Exper. Med. 

 and Biol., 1909, vii, 55). 



Acetone soluble antigen does have some slight superiority over the others 



