EN
The authors describe the technique for complement fixing tests. More than 27.000 blood samples have been examined. The preparation of antigens from the peritoneal exudate of mice and from the choroiallantoic membrane of chick embryos are described. The authors specify the optimal test conditions, the optimal working dilution of the antigen and emphasize the advantages of the icebox incubation before the water-bath incubation. Since the mouse antigens have a higher fixability they should be preferred. The interpretation of the results is reported and attention is drawn to the phenomenon of the long term persistence of the complement fixing antibodies. The paper contains an analysis of the significance of the antibody titre determination and their dynamics. The importance of the complement fixing test for toxoplasmosis with regard to its specificity, sensitivity, stability and reproducibility is discussed.