492 'may clarify the somewhat incomplete description of these Experiments given by Professor Simpson in his Necessarily contracted Reports.
There is no doubt about the animals, upon which he experimented, having died of plague. Professor Simpson used calves, pigs, sheep, fowls, etc., which in Nature are practically insusceptible to plague infection. No one doubts their insusceptibility, but such an immunity is not absolute, and the production of the disease in such animals must be regarded as simple induction of plague in animals, insusceptible to the disease, by the administration of enormous doses of highly infective material, which eventually overcame the Natural but not absolute insusceptibility. Simpson certainly used Enormous doses and although correct in his post-mortem and bacteriological results, interpreted his findings in a manner somewhat dogmatic, and Not quite in harmony with what is generally recognised by plague specialists.
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