Antigens, prepared from 17 strains of Haemophilus paragallinarum by treatment with potassium thiocyanate followed by sonication, uniformly agglutinated glutaraldehyde-fixed chicken erythrocytes and formed specific hemagglutination inhibition antibodies in rabbits. Attempts were made to classify the strains into serotypes by a combination of cross-hemagglutination inhibition and cross-absorption...

The hemolysis-in-gel method for detection of antibodies to rubella virus gave results which correlated well with results of hemagglutination inhibition and neutralization tests. With a diffusion time of 24 or 48 h, a linear correlation was obtained between the logarithm of antibody concentration and the diameter of the hemolytic zone. Fourfold, and even twofold, differences in serum antibody co...