THE TECHNIQUE AND PRACTICAL APPLICATIONS OF THE COM- PLEMENT-FIXATION TEST FOR DIAGNOSIS OF INFECTION WITH ENCEPHALITIS VIRUSES'-

Some questions have arisen about the practicability of the complement-fixa-tion test in the diagnosis of human encephalitides. These questions refer mainly to the following points: Laboratory procedures. (1) Inactivation and preservation of antigens; use of irradiated and lyophilized material. (2) Production of animal hyperimmune sera for standardization of antigens. (3) Existence of cross reactions within certain groups of viruses, especially the equine encephalomyelitis group. Practical applications. Use of the complement-fixation test with human sera, especially the detection of false positive and false negative reactions. The methods for the preparation of antigens and hyperimmune sera as well as the technique of the test have been described in detail (Casals and Palacios, 1941; Casals, 1941, 1943). The only modification thus far introduced in the preparation of antigens is that centrifugation at 6,000 rpm in the Pickels.(1942) centrifuge substitutes for the original method, centrifugation at 3,500 rpm in the Swedish angle centrifuge