ACCORDING to Science Service, Washington, D.C. (June 10) the compound rotenone is the latest addition to chemical methods of controlling insect pests of crops, animals and the household. It was first discovered through the use of plants containing it as fish poisons by natives of tropical countries. Its principal commercial source is the derris plant of the East Indies, but it is also present in a South American plant called ‘cube’ and in the North American plant popularly termed ‘devil's shoestring’. All the plants that are known to yield rotenone are members of the natural order Legum-inos ¦. Rotenone is exceedingly toxic to many kinds of insects but quite harmless to man and all warmblooded vertebrates. While not all insects are susceptible to its toxic effects, in the form of sprays and other preparations, it has been shown to be fifteen times as toxic as a nicotine spray when used as a contact poison against aphides, and thirty times as toxic as acid lead arsenate, when tested as an internal poison against certain caterpillars.