Titration of botulinum toxins for lethal toxicity by intravenous injection into mice.

Clostridium botulinum type A - F toxins can be titrated by the time-to-death method by iv injection into mice. The time to death is not dependent upon the molecular size, but upon the immunological type of the toxin. It is necessary to assure complete activation of the activable toxin produced by nonproteolytic as well as a certain proteolytic strains before subjecting to titration by the iv injection method.