1972 Volume 25 Issue 1 Pages 15-23
A rapid bio-assay method for α-toxin of Clostridium perfringens was described. The method is principally based on the parallel line assay method, using a stable reference toxin. The method consists of intravenous injections into mice with two dilutions of each toxin sample and a reference toxin, determination of the survival time in minutes, conversion of the time to an appropriate score and calculation of the relative toxicity. The estimated LD50 agreed fairly well with that actually determined. The fiducial limits of LD50 was about 30% when 10 mice were used for each specimen. It became possible to determine the toxicity of 10 samples in a few hours. Mice were more sensitive to the toxin given by the iv route than by the ip route, in contrast to the result of Lynch and Moskowitz (1968) .