[Derivation of a formula based on the central-limit theorem for evaluating the effectiveness of immunization]

The theoretical formula for the determination of the degree of resistance in the animal immunized with equal doses of the antigen has been deduced in accordance with the known of Kapteyn by presenting the immunological transformation of the organism, caused by the introduction of the antigen, as the result of the consecutive action of a multitude of accidental independent or slightly connected reasons and by using the liminal infective dose as the quantitative index of this transformation.