Statistical Aspects of the Independent Joint Action of Poisons, Particularly Insecticides

I. The Toxicity of a Mixture of Poisons



Bliss's (1939) statistical treatment of the hypothesis of the independent joint action of poisons is extended and revised. The possibility of negative correlation in resistance is considered, and the bivariate normal correlation coefficient is used to measure correlation in resistance. There are interesting characteristics of the dosage-mortality curve for a mixture of poisons the resistances to which are log-normally distributed: these are described. The question of whether a mixture of poisons is more toxic if they act similarly or independently is discussed.