Depletion of Gamma Isomer of Benzene Hexachloride in Cattle Dipping-Fluids

Abstract

BENZENE hexachloride dips are highly effective for the control of cattle ticks and have been used extensively for this purpose. However, it was reported from South Africa¹ and Australia² that the toxicity of the fluid declined after the initial charging of the vat, even though chemical analyses indicated little loss in the content of benzene hexachloride. The methods of chemical analysis used in the investigations mentioned above were, however, not specific for the gamma isomer, and the assumption had to be made that its concentration maintained a constant relation to that of the total benzene hexachloride. This assumption has now been found to be unjustifiable, as estimation of the quantities of isomers in cattle dipping-fluids, rendered possible by the development of an appropriate method of adsorption chromatography³, indicates a depletion of the gamma isomer in dips sufficiently marked to account for the observed loss of toxicity to ticks.