ingredient in birth-control pills, are tropical forest products. Scientists are convinced that further study would uncover forest plants that repel insects and other herbivores, plant-eating animals. These substances might provide a harmless substitute for the chemical pesticides that are widely used in agriculture and are harmful to all living beings. Robert Allen of the lnternational Union for the Conservation of Nature and Natural Resources emphasized the potential of tropical forest products. He said,” Tropical trees, thanks to their constant battle with her bivores, are source books of chemical invention of which man has scarcely turned the pages.”