SEROLOGICAL METHODS IN THE STUDY OF PROTOZOA 427 



tissues, thus amounting to a non-specific Wassermann test; (2) 

 extracts of organs from animals infected with trypanosomes ; and 

 (3) extracts of parasites which have been more or less completely 

 isolated from the blood and body fluids of the host. 



Work on the non-specific Wassermann test was initiated by 

 Landsteiner, Miiller and Potzl (1907) and taken as a whole 

 gives rather inconsistent results. The following conclusions are, 

 however, probably justified: Serums from rabbits infected with 

 various species of trypanosomes frequently give positive Wasser- 

 mann reactions. In this connection Landsteiner and van der Scheer 

 (1927) have shown that the serums of rabbits become strongly 

 Wassermann positive when the animals are immunized with 

 dead trypanosomes (T. equiperdum), but less regularly so when 

 they are infected. (Since serums from seemingly normal rabbits 

 also frequently yield positive Wassermann reactions, most in- 

 vestigators have been careful to use only animals which are 

 negative before they begin their experiments.) Serums from 

 other infected animals sometimes show positive Wassermann tests, 

 but are too inconstant to be used for diagnosis. Serums from man 

 infected with trypanosomiasis uncomplicated by syphilis or yaws, 

 in spite of several positive reports, probably do not give positive 

 Wassermann tests, especially with the modern perfection of 

 technique. 



Delia Vida (1907) and Weber (1907) were probably the first 

 to attempt specific complement fixation in trypanosomiasis and 

 used extracts of organs from infected animals. With the exception 

 of Hartoch and YakimofT (1908) the early work was in the 

 main inconclusive. This. Levaditi and Alutermilch (1909) at- 

 tributed to the use of weak non-purified test antigens. Accord- 

 ingly, they isolated their trypanosomes from blood constituents by 

 washing and centrifuging; then they either suspended them in 

 saline or after drying in vacuo over sulphuric acid and pulverizing, 

 extracted 0.05 gram of the powder in four or five cubic centi- 

 meters of saline at 37° C. for one hour. \\'orking with T. evansi 

 and several strains of T. brucei, they obtained such specific results 

 for the genus (not for the species) that they concluded the 

 test could be used to detect infection, but not specific infection. 

 Mcintosh (1910), in parallel Wassermann and specific com- 

 plement fixation tests, concluded that the latter gave stronger 

 reactions. 



