154 APPLIED IMMUNOLOGY 



however, have shown it to be a reliable method of diag- 

 nosis. The technic of the reaction is the same as that 

 for the Wassermann reaction. The antigen used con- 

 sists of the fluid from hydatid cysts of sheep affected 

 with the disease. Suitable amounts of this fluid when 

 brought in contact with the blood-serum of patients 

 suffering from echinococcus disease will cause comple- 

 ment fixation. 



Complement-fixation Reaction in Typhoid Fever 

 In reporting the results of the complement-fixa- 

 tion reaction in typhoid fever, Garbat {A?n. Jr. Med, 

 Sc, July, 1914) finds that the serum of practically all 

 typhoid fever patients sooner or later gives a positive 

 complement-fixation reaction. A highly polyvalent 

 antigen properly prepared is absolutely essential in 

 order to obtain a maximum of positive results. A 

 positive complement-fixation test throws great cor- 

 roborative diagnostic weight on the side of a doubtful 

 or positive Widal reaction. Occasionally the test is 

 positive before the Widal or blood culture, but usually 

 not before the end of the second week. It generally 

 persists for about six weeks after recovery. 



Complement-fixation Reaction in Tuberculosis 

 Emplo^^ing as antigen a simple emulsion of liv- 

 ing tubercle bacilli, ]McIntosh, Fildes, and RadclifFe 

 {Lancet, Aug. 22, 1914) obtained positive comple- 



