A specific antivenin against crotalus venom can be prepared bv the immunization of goats. A specific antivenin against water moccasin venom can be produced by the immunization of goats with this venom, modified by hydrochloric acid. Immunization with the unmodified venom is very difficult.
The toxicity of crotalus venom is diminished more than fifty percent. by passage through a Chamberland filter. There is a simple relation between the toxicity and the body weight for guinea-pigs weighing from 250 to 500 grams. Smaller guinea-pigs (125 grams) are comparatively less resistant. The toxicity is smaller by subcutaneous than by intraperitoneal injection (guinea-pigs), or by intravenous injection (rabbits). White rats are very resistant.
The toxicity of cobra venom is not measurably diminished by filtration through a Chamberland filter. The relation between the amount of venom and the corresponding time of death is very regular, and can be expressed by a curve of asymptotic nature. Lecithin does not increase the toxicity.
The tracings representing toxin-antitoxin neutralization for the three venoms (crotalus, cobra and moccasin) show deviation from the straight line. This deviation is most pronounced for the toxic quota of the venoms. The tracing representing crotalus venomantivenin neutralization, determined on guinea-pigs, can, within errors of experiment, be expressed by the equation:
Free toxin · Free antitoxin = K · toxin-antitoxin.
The corresponding tracing determined on rabbits is somewhat different, but both tracings are much more markedly curved than that for cobra venom-antivenin. The neutralization tracing of water moccasin venom shows the peculiarity, that small amounts of antivenin decrease the toxicity to a minimum, but the toxicity is again increased by further addition of antitoxin.
The tracing representing neutralization of the haemolysins of the three venoms are different from the tracings of neutralization of the toxins, and approach very closely to a straight line. Still, in all instances, the determinations with great concentrations of antilysin show pronounced deviation, perhaps due to some dissociation of the toxin-antitoxin combination.