Assay of Botulinum a Toxin with Goldfish.∗

Summary A method has been established for the assay of botulinum A toxin in goldfish. When 10 fish are inoculated per dilution and the dilution interval is 10-fold, the end point distribution was found to have a standard deviation of about 0.24 log unit. The end points are strongly temperature dependent; they decrease about a hundred-fold for a temperature decrease of 15°C. The end point in fish at 37° has approximately the same value as that in mice.