Ein Test zur Prüfung der Wirksamkeit insektizider Substanzen und ein Beitrag zum Mechanismus der Wirkung von DDT und HCC

Abstract

The degree of activity and mode of action of DDT, gamma-benzene hexachloride (Standard), gammexane (commercial product), veratrin, and chloral hydrate were investigated by dissolving a certain amt. of the substance in 1 to 2 ml. of absolute alcohol and dropping the soln. on the abdomen of flies (Calliphora erythrocephala, Lucilia caesar, and Phormia.) Cultivation methods for these flies have been previously described. The amts. for the M.L.D. of the insects after 24 hrs. were 0.015 microg. for the gamma-benzene hexachloride standard, 0.21 microg. for the commercial gammexane, 0.21 microg. for DDT, 39 microg. for veratrin, and 45.6 microg. for chloral hydrate. In this test it was detd. that of the organs of frogs and mice killed by subcut. injns. of DDT, the brain showed the smallest amt. of active DDT, while for the other organs, because of the small number of test flies used, the results were not consistent. Maggots were killed only by crystalline DDT. Sections of the central nervous system of flies, pupae, and maggots killed by DDT showed no morphological changes. DDT and gammexane appeared to infiltrate into the interstices of the chitin armor, which explained the immunity of the pupae.