“…Eagleton (1891-1925) of the Wellcome Physiological Research Laboratories proposed a method to standardise the potency of tuberculin by measuring its 'minimum lethal dose' in guinea pigs. 38 It was the potency rather than toxicity of the vaccine that was in question, but the latter was a convenient proxy for the former, since it was harder to test the strength of a vaccine than to find the lowest dose that would cause death. The test was seriously flawed, because susceptibility to toxins varies both between and within species, and it took only one idiosyncratic result to skew the findings.…”