Bothrops and rattlesnake venom under the experimental conditions cited were not efficacious in producing a refractory state as concerns the Shwartzman phenomenon. Copperhead and moccasin venom were efficacious. The minimum effective dose of moccasin venom necessary to produce a refractory state as concerns the Shwartzman phenomenon for the sample of moccasin venom used was found to be 0.04 mgm. given intradermally.
Solutions of moccasin venom made from different samples of pooled venom differed markedly in their ability to produce a refractory state against the Shwartzman phenomenon. This difference was due to the fact that the venoms of individual moccasin snakes vary in their content of the refractory-producing factor. Some moccasin venoms have been found which were not capable of producing a refractory state.
The potency of a venom with respect to the production of the refractory state (R.P.) was titrated.
There was no relationship between the neurotoxicity of the individual moccasin venoms and their ability to produce a refractory state as concerns the Shwartzman phenomenon.