The Flocculation Test and the Law of Mass Action

Abstract

Experiments are presented which show that flocculation time in both the Ramon and Dean-Webb methods is the resultant of two different interacting variables which affect the velocity of precipitation. One is the independent variable of interest, namely, the equivalence ratio. The other is the mass-law effect, that is, the variation from tube to tube of the product of the concentrations of the reactants which is a necessary consequence of keeping one reactant constant. A new, equally simple method is proposed which eliminates the mass-law effect by maintaining a constant product of concentrations. Comparisons of all three methods are presented in both the diphtheria and tetanus systems.