Insecticidal Power and Microscopical Structure of Residual Films of Benzene Hexachloride

Abstract

IN some recent experiments with samples of the γ-isomer of benzene hexachloride (1,2,3,4,5,6-hexachlorocyclohexane), in which adult beetles of Dermestes maculatus Deg. were tested on residual films prepared on glass plates by a recently devised method¹, it was found that in films formed from chloroform solutions, a certain sample of ‘technical' grade material (I) was more insecticidal than the corresponding ‘refined' sample (II) and ‘refined' (III) and ‘technical' (IV) samples of different manufacture. These unexpected observations were the reverse of those obtained by other investigators testing the same samples by different methods². Furthermore, when residual films of the insecticides in a light, refined paraffin spray oil were prepared and tested in this laboratory, samples (II) and (III) were at least as toxic as (I).