Note 597 — Chapter XII · ARTIFICIAL IMMUNITY AGAINST TOXINS
Francis G. Binnie translation
Berlin klin. Wchnschr., 1901, S. 157. The idea of immunising monkeys against diphtheria was suggested to von Behring by the fact that the immunity conferred by serums was the more durable the nearer the relation between the serum used and the blood of the species which receives the protective injection. Von Behring supposed that the diphtheria antitoxin, introduced into the human body, would be maintained there longer, if the antitoxic serum injected came from monkeys, species much nearer man than is the horse, the usual source of antidiphtheria serum. The immunity conferred by this horse serum is generally of very short duration.