The vigour with which this plant grows in aquatic systems, and its ability to extract pollutants, prompted us to see whether it could be used as a feed supplement for animals. The approximate composition of the root and shoot system is given in Table 9. The results indicate that the plants contained, on average, about 14~o protein. Preliminary feeding trials using grasshoppers Zonocerus varigatus were made by taking 100 grasshoppers in a wire-mesh cage along with 66.5 g of fresh leaves of Pistia plants. In 3 h the insects consumed 22-5 g of the plant. After a further period the leaves were completely consumed. Further nutritional experiments using higher animals, the amino acid composition and the presence of any possible toxic substances in the plants are in progress.